Windows ga (#358)

* Enhance Cloud TTS with navigation controls and shared UI overlay in desktop app

* Refactor Cloud TTS voice settings and remove standalone settings overlay on desktop app

* Persist reader window state and improve slider interaction in desktop app

* Improve PDF page transitions and refine focus management in desktop app

* Refactor scrollbar interaction and adjust desktop modal focus handling

* Improve PDF sidecar synchronization and cross-platform metadata compatibility

* Refactor PDF annotation comment logic to shared module and implement Desktop UI

* Refactor reader screen to use tap-to-toggle and full-width styling in desktop app

* Refactor reader workspace layout and chrome-panel interactions

* Implement global search keyboard shortcuts and focusable chrome layers

* Implement flavor-specific legal links and update the About UI

* Refactor reader UI controls on desktop app

* Enhance desktop folder sync with background metadata extraction and improved error handling

* Refactor Library UI and remove redundant Home tab in desktop app

* Add custom tooltips to reader icon buttons in desktop app

* Integrate app theme controls into reader interfaces on desktop

* Add right-to-left pagination support and improve focus restoration on desktop app

* Improve EPUB pagination geometry and diagnostic logging for layout cutoffs on desktop app

* Update desktop reader defaults and implement settings migration

* Implement block-based position tracking in ReaderLocator

* Enhance EPUB highlighting reliability in desktop app

* Add support for custom reader themes and update highlight palette logic in desktop app

* Replace the Tools panel with a "More" dropdown menu and refactor account UI

* Implement account profile header in desktop sidebar

* Implement cloud sync reliability improvements and sidebar toggle on desktop app

* Improve EPUB annotation synchronization and highlight mapping accuracy in desktop app

* Integrate WebView2 for EPUB vertical rendering on Windows

* Refactor reader layout logic and enhance WebView2 diagnostics

* Improve vertical reading layout and WebView2 resizing on Desktop

* Refine vertical reading mode layout and margin handling

* Enhance reader locator precision and Desktop mode-switching reliability

* Implement chapter-level caching and warm-start pagination in desktop app

* Replace bundled KCEF with native system webviews via SWT

* Refactor EPUB page info bar visibility and layout logic

* Improve PDF toolbar persistence and fix tab reactivation logic

* Enable multi-selection and bulk operations for custom fonts

* Refactor instrumentation tests

* Add EPUB UI test fixture and initial instrumentation tests

* Expand EpubReader UI tests and improve accessibility

* Add instrumentation tests and test tags for library and reader screens

* Enhance OPDS parser logic and catalog integration

* Add support for toggling local synchronization on a per-folder basis.

* Implement tri-state sizing for the TTS overlay

* Persist TTS overlay size across sessions

* Refactor reader brightness control and add incremental step buttons

* Improve CSS support, pagination control, and style-aware semantic caching

* Improve link handling, interaction, and diagnostics in the paginated reader

* crash fixes

* Implement persistent pending removal for external files

* Implement book-specific word replacements

* Add native vertical reading mode with custom renderer

* Implement text selection and navigation improvements for the native vertical reader

* Implement locator-based navigation and improved vertical scrolling in native vertical mode in epub

* Implement lazy loading and chapter prefetching for native vertical reader

* Improve window lifecycle and disposal handling on Desktop

* Optimize vertical reading performance in desktop app

* Enhance TTS start accuracy and diagnostic logging on desktop

* Refactor AI settings visibility on desktop

* Improve pagination height measurement and enhance cutoff diagnostics

* Implement lifecycle management and improve justified text splitting for pagination

* Refine AI usage tracking and force AI feature visibility on Desktop

* Add descriptive context comments and usage examples to string and plural resources.

* Optimize performance and memory usage in search and state mapping

* Replace reader page sliders with minimal slider and navigation controls

* Add support for CBT comic archives

* Harden file path validation and XML parsing to prevent security vulnerabilities

* Implement local account profile caching and optimize desktop performance

* Improve desktop persistence reliability and add Linux secure storage support

* Improved PDF zoom stability and layout prediction during zoom commits

* Improved PDF spread layout prediction, reader focus restoration, and account profile caching

* Enhance highlight precision and scoping using block-local offsets and CFIs

* Enhance cloud book content synchronization and background downloads

* Implement granular timestamp tracking for reading positions and PDF annotations

* Restrict diagnostic logging and stack traces to debug builds

* Refine PDF page gaps and reader chrome interaction logic

* Refactor PDF highlight rendering and overhaul Desktop sidebar UI

* Implement a new interaction dock and undo/redo history for PDF annotations in desktop

* Enhance PDF color picker and improve navigation scroll restoration

* Add highlight palette customization and improve selection menu UI in desktop app epub reader

* Enhance desktop shelf management and library organization

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopAccountProfileRepository.kt

@@ -8,18 +8,49 @@ import kotlinx.serialization.json.JsonObject
 import kotlinx.serialization.json.contentOrNull
 import kotlinx.serialization.json.jsonObject
 import kotlinx.serialization.json.jsonPrimitive
+import java.io.File
 import java.net.HttpURLConnection
 import java.net.URL
 import java.net.URLEncoder
+import java.util.Properties
 
 internal data class DesktopAccountProfile(
     val isProUser: Boolean = false,
-    val credits: Int = 0
+    val credits: Int = 0,
+    val fetchedAtEpochMillis: Long = 0L
 )
 
+// Credits and Pro status are server-owned, so startup only trusts a recent snapshot.
+internal const val DesktopAccountProfileCacheTtlMillis: Long = 30L * 60L * 1000L
+
+internal fun DesktopAccountProfile.isFresh(
+    nowEpochMillis: Long = System.currentTimeMillis(),
+    ttlMillis: Long = DesktopAccountProfileCacheTtlMillis
+): Boolean {
+    if (fetchedAtEpochMillis <= 0L || ttlMillis <= 0L) return false
+    val ageMillis = nowEpochMillis - fetchedAtEpochMillis
+    return ageMillis in 0L..ttlMillis
+}
+
 internal class DesktopAccountProfileRepository(
-    private val config: DesktopCloudConfig
+    private val config: DesktopCloudConfig,
+    private val store: DesktopAccountProfileStore = DesktopAccountProfileStore()
 ) {
+    fun cachedProfile(
+        uid: String,
+        nowEpochMillis: Long = System.currentTimeMillis()
+    ): DesktopAccountProfile? {
+        return store.load(uid)?.takeIf { profile -> profile.isFresh(nowEpochMillis) }
+    }
+
+    fun saveFetchedProfile(uid: String, profile: DesktopAccountProfile) {
+        store.save(uid, profile)
+    }
+
+    fun clearCachedProfiles() {
+        store.clear()
+    }
+
     suspend fun fetchProfile(uid: String, idToken: String): DesktopAccountProfile = withContext(Dispatchers.IO) {
         if (uid.isBlank() || idToken.isBlank()) return@withContext DesktopAccountProfile()
         val url = "https://firestore.googleapis.com/v1/projects/${urlEncode(config.firebaseProjectId)}/databases/(default)/documents/users/${urlEncode(uid)}"
@@ -31,23 +62,60 @@ internal class DesktopAccountProfileRepository(
             readTimeout = 20_000
         }
         try {
-            if (connection.responseCode == HttpURLConnection.HTTP_NOT_FOUND) return@withContext DesktopAccountProfile()
+            if (connection.responseCode == HttpURLConnection.HTTP_NOT_FOUND) {
+                return@withContext DesktopAccountProfile(fetchedAtEpochMillis = System.currentTimeMillis())
+            }
             val stream = if (connection.responseCode in 200..299) connection.inputStream else connection.errorStream
             val text = stream?.bufferedReader(Charsets.UTF_8)?.use { it.readText() }.orEmpty()
             if (connection.responseCode !in 200..299) {
                 throw IllegalStateException("Could not check account status: HTTP ${connection.responseCode}")
             }
             val fields = DesktopAccountJson.parseToJsonElement(text).jsonObject["fields"].jsonObjectOrNull()
-            DesktopAccountProfile(
+            val profile = DesktopAccountProfile(
                 isProUser = fields?.booleanField("isPro") == true,
-                credits = fields?.numberField("credits")?.toInt() ?: 0
+                credits = fields?.numberField("credits")?.toInt() ?: 0,
+                fetchedAtEpochMillis = System.currentTimeMillis()
             )
+            profile
         } finally {
             connection.disconnect()
         }
     }
 }
 
+internal class DesktopAccountProfileStore(
+    private val settingsFile: File = File(desktopUserConfigRoot(), "account_profile.properties")
+) {
+    fun load(uid: String): DesktopAccountProfile? {
+        if (uid.isBlank() || !settingsFile.isFile) return null
+        val properties = Properties()
+        return runCatching {
+            settingsFile.inputStream().use(properties::load)
+            if (properties.getProperty("uid", "") != uid) return null
+            DesktopAccountProfile(
+                isProUser = properties.getProperty("isProUser", "false").toBooleanStrictOrNull() ?: false,
+                credits = properties.getProperty("credits", "0").toIntOrNull() ?: 0,
+                fetchedAtEpochMillis = properties.getProperty("fetchedAtEpochMillis", "0").toLongOrNull() ?: 0L
+            )
+        }.getOrNull()
+    }
+
+    fun save(uid: String, profile: DesktopAccountProfile) {
+        if (uid.isBlank()) return
+        val properties = Properties().apply {
+            setProperty("uid", uid)
+            setProperty("isProUser", profile.isProUser.toString())
+            setProperty("credits", profile.credits.toString())
+            setProperty("fetchedAtEpochMillis", profile.fetchedAtEpochMillis.toString())
+        }
+        settingsFile.storePropertiesAtomically(properties, "Episteme desktop account profile")
+    }
+
+    fun clear() {
+        settingsFile.delete()
+    }
+}
+
 private val DesktopAccountJson = Json { ignoreUnknownKeys = true }
 
 private fun JsonObject?.booleanField(key: String): Boolean? {

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopAiByokStore.kt

@@ -13,6 +13,7 @@ import com.sun.jna.win32.StdCallLibrary
 import java.io.File
 import java.util.Base64
 import java.util.Properties
+import java.util.concurrent.TimeUnit
 
 private const val WINDOWS_CRED_TYPE_GENERIC = 1
 private const val WINDOWS_CRED_PERSIST_LOCAL_MACHINE = 2
@@ -60,7 +61,7 @@ internal class DesktopAiByokStore(
                 loadedSettings.copy(ttsModel = GEMINI_CLOUD_TTS_MODEL_ID)
             } else {
                 loadedSettings
-            }
+            }.toDesktopPersistableAiSettings()
             if (secureStorageAvailable &&
                 (legacyGeminiKey.isNotBlank() || legacyGroqKey.isNotBlank() || settings != loadedSettings)
             ) {
@@ -82,7 +83,7 @@ internal class DesktopAiByokStore(
     }
 
     fun save(settings: ReaderAiByokSettings) {
-        val sanitized = settings.sanitized()
+        val sanitized = settings.toDesktopPersistableAiSettings()
         logDesktopTts(
             "settings_save_start file=\"${settingsFile.absolutePath.desktopTtsPreview(220)}\" " +
                 "secureStorage=${secretCodec.isAvailable} geminiKey=${sanitized.geminiKey.isNotBlank()} " +
@@ -101,9 +102,7 @@ internal class DesktopAiByokStore(
             setProperty("ttsSpeakerId", sanitized.ttsSpeakerId)
         }
         settingsFile.parentFile?.mkdirs()
-        settingsFile.outputStream().use { output ->
-            properties.store(output, "Episteme desktop AI keys and models")
-        }
+        settingsFile.storePropertiesAtomically(properties, "Episteme desktop AI keys and models")
         logDesktopTts(
             "settings_save_complete geminiProtected=${properties.getProperty(GeminiKey, "").isNotBlank()} " +
                 "groqProtected=${properties.getProperty(GroqKey, "").isNotBlank()}"
@@ -173,10 +172,10 @@ internal interface DesktopSecretCodec {
     companion object {
         fun platform(): DesktopSecretCodec {
             val osName = System.getProperty("os.name").orEmpty()
-            val codec = if (osName.startsWith("Windows", ignoreCase = true)) {
-                WindowsSecretCodec
-            } else {
-                UnavailableDesktopSecretCodec
+            val codec = when {
+                osName.startsWith("Windows", ignoreCase = true) -> WindowsSecretCodec
+                osName.contains("Linux", ignoreCase = true) -> LinuxSecretToolCodec()
+                else -> UnavailableDesktopSecretCodec
             }
             logDesktopTts("settings_platform os=\"${osName.desktopTtsPreview()}\" codec=${codec.name}")
             return codec
@@ -193,6 +192,160 @@ private object UnavailableDesktopSecretCodec : DesktopSecretCodec {
     override fun unprotect(value: String): String = ""
 }
 
+internal data class DesktopSecretCommandResult(
+    val exitCode: Int,
+    val stdout: String,
+    val stderr: String
+) {
+    val isSuccess: Boolean get() = exitCode == 0
+    val errorSummary: String
+        get() = stderr.ifBlank { stdout }.desktopTtsPreview(240).ifBlank { "exit code $exitCode" }
+}
+
+internal interface DesktopSecretCommandRunner {
+    fun isExecutableAvailable(command: String): Boolean
+    fun run(command: List<String>, input: String? = null, timeoutMillis: Long = 5_000L): DesktopSecretCommandResult
+}
+
+private object DesktopProcessSecretCommandRunner : DesktopSecretCommandRunner {
+    override fun isExecutableAvailable(command: String): Boolean {
+        val path = System.getenv("PATH").orEmpty()
+        return path.split(File.pathSeparator)
+            .asSequence()
+            .map { it.trim() }
+            .filter { it.isNotEmpty() }
+            .any { directory ->
+                File(directory, command).let { it.isFile && it.canExecute() }
+            }
+    }
+
+    override fun run(command: List<String>, input: String?, timeoutMillis: Long): DesktopSecretCommandResult {
+        require(command.isNotEmpty()) { "Secret command cannot be empty." }
+        val process = ProcessBuilder(command).start()
+        input?.let { value ->
+            process.outputStream.use { output ->
+                output.write(value.toByteArray(Charsets.UTF_8))
+            }
+        } ?: process.outputStream.close()
+
+        val completed = process.waitFor(timeoutMillis, TimeUnit.MILLISECONDS)
+        if (!completed) {
+            process.destroyForcibly()
+            throw IllegalStateException("Timed out waiting for ${command.first()} secure storage command.")
+        }
+        return DesktopSecretCommandResult(
+            exitCode = process.exitValue(),
+            stdout = process.inputStream.readBytes().toString(Charsets.UTF_8),
+            stderr = process.errorStream.readBytes().toString(Charsets.UTF_8)
+        )
+    }
+}
+
+internal class LinuxSecretToolCodec(
+    private val commandRunner: DesktopSecretCommandRunner = DesktopProcessSecretCommandRunner
+) : DesktopSecretCodec {
+    override val name: String = "linux-secret-tool"
+
+    override val isAvailable: Boolean by lazy {
+        val available = commandRunner.isExecutableAvailable(SecretToolCommand) &&
+            runCatching {
+                commandRunner.run(listOf(SecretToolCommand, "--help"), timeoutMillis = 3_000L).isSuccess
+            }.getOrDefault(false)
+        logDesktopTts("settings_linux_secret_tool_available available=$available")
+        available
+    }
+
+    override fun protect(value: String): String {
+        return protect("secret", value)
+    }
+
+    override fun unprotect(value: String): String {
+        return unprotect("secret", value)
+    }
+
+    override fun protect(keyName: String, value: String): String {
+        if (!isAvailable) {
+            throw IllegalStateException(
+                "Linux Secret Service is unavailable. Install libsecret-tools and make sure a desktop keyring is running."
+            )
+        }
+        val key = linuxSecretKey(keyName)
+        logDesktopTts("settings_linux_secret_tool_write_start key=$keyName valueChars=${value.length}")
+        val result = commandRunner.run(
+            command = listOf(
+                SecretToolCommand,
+                "store",
+                "--label",
+                "Episteme $keyName",
+                SecretToolApplicationAttribute,
+                SecretToolApplicationValue,
+                SecretToolKeyAttribute,
+                key
+            ),
+            input = value,
+            timeoutMillis = 15_000L
+        )
+        logDesktopTts("settings_linux_secret_tool_write_result key=$keyName exit=${result.exitCode}")
+        if (!result.isSuccess) {
+            throw IllegalStateException("Linux Secret Service write failed: ${result.errorSummary}")
+        }
+        return Prefix + key
+    }
+
+    override fun unprotect(keyName: String, value: String): String {
+        if (!isAvailable) return ""
+        val key = value.removePrefix(Prefix).takeIf { value.startsWith(Prefix) } ?: linuxSecretKey(keyName)
+        logDesktopTts("settings_linux_secret_tool_read_start key=$keyName")
+        val result = commandRunner.run(
+            command = listOf(
+                SecretToolCommand,
+                "lookup",
+                SecretToolApplicationAttribute,
+                SecretToolApplicationValue,
+                SecretToolKeyAttribute,
+                key
+            ),
+            timeoutMillis = 8_000L
+        )
+        logDesktopTts("settings_linux_secret_tool_read_result key=$keyName exit=${result.exitCode} chars=${result.stdout.length}")
+        if (!result.isSuccess) {
+            throw IllegalStateException("Linux Secret Service read failed: ${result.errorSummary}")
+        }
+        return result.stdout.trimEnd('\r', '\n')
+    }
+
+    override fun delete(keyName: String) {
+        val key = linuxSecretKey(keyName)
+        runCatching {
+            commandRunner.run(
+                command = listOf(
+                    SecretToolCommand,
+                    "clear",
+                    SecretToolApplicationAttribute,
+                    SecretToolApplicationValue,
+                    SecretToolKeyAttribute,
+                    key
+                ),
+                timeoutMillis = 8_000L
+            )
+        }.onFailure { error ->
+            logDesktopTts("settings_linux_secret_tool_delete_failed key=$keyName error=\"${error.desktopTtsSummary()}\"")
+        }
+    }
+
+    private fun linuxSecretKey(keyName: String): String {
+        return "Episteme.Reader.$keyName"
+    }
+
+    private companion object {
+        const val Prefix = "secret-tool:"
+        const val SecretToolCommand = "secret-tool"
+        const val SecretToolApplicationAttribute = "application"
+        const val SecretToolApplicationValue = "Episteme.Reader"
+        const val SecretToolKeyAttribute = "key"
+    }
+}
+
 private object WindowsSecretCodec : DesktopSecretCodec {
     override val name: String = "windows"
 

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopAiHub.kt

@@ -14,11 +14,7 @@ import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.ContentCopy
 import androidx.compose.material.icons.filled.Delete
-import androidx.compose.material.icons.filled.Settings
-import androidx.compose.material.icons.filled.VolumeUp
-import androidx.compose.material3.AssistChip
 import androidx.compose.material3.Button
-import androidx.compose.material3.FilterChip
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
@@ -42,13 +38,8 @@ import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
-import com.aryan.reader.shared.ReaderAiByokSettings
-import com.aryan.reader.shared.ReaderCloudTtsState
-import com.aryan.reader.shared.ReaderCloudTtsVoices
-import com.aryan.reader.shared.ReaderTtsCacheSummary
 import com.aryan.reader.shared.RecapResult
 import com.aryan.reader.shared.SummarizationResult
-import com.aryan.reader.shared.readerCloudTtsVoiceById
 import com.aryan.reader.shared.ui.SharedMarkdownText
 import com.aryan.reader.shared.ui.readerString
 
@@ -345,169 +336,3 @@ private fun DesktopSummaryCachePanel(
         }
     }
 }
-
-@Composable
-internal fun DesktopCloudTtsChromeControls(
-    settings: ReaderAiByokSettings,
-    cloudTts: ReaderCloudTtsState,
-    credits: Int,
-    showCredits: Boolean,
-    onRead: () -> Unit,
-    onPauseResume: () -> Unit,
-    onStop: () -> Unit,
-    onOpenSettings: () -> Unit
-) {
-    val sanitized = settings.sanitized()
-    val voice = readerCloudTtsVoiceById(sanitized.ttsSpeakerId)
-    val ttsBusy = cloudTts.isLoading || cloudTts.isPlaying || cloudTts.isPaused
-    Surface(
-        color = MaterialTheme.colorScheme.surfaceContainerLow,
-        shape = RoundedCornerShape(8.dp),
-        tonalElevation = 1.dp
-    ) {
-        Row(
-            modifier = Modifier.fillMaxWidth().padding(horizontal = 10.dp, vertical = 6.dp),
-            horizontalArrangement = Arrangement.spacedBy(8.dp),
-            verticalAlignment = Alignment.CenterVertically
-        ) {
-            Icon(Icons.Default.VolumeUp, contentDescription = null, tint = MaterialTheme.colorScheme.primary)
-            Column(modifier = Modifier.weight(1f)) {
-                Text(
-                    when {
-                        cloudTts.isLoading -> readerString("desktop_preparing_audio", "Preparing audio")
-                        cloudTts.isPaused -> readerString("desktop_paused", "Paused")
-                        cloudTts.isPlaying -> readerString("label_reading", "Reading")
-                        sanitized.isCloudTtsAvailable -> readerString("desktop_cloud_tts_ready", "Cloud TTS ready")
-                        else -> readerString("desktop_cloud_tts_unavailable", "Cloud TTS unavailable")
-                    },
-                    style = MaterialTheme.typography.labelLarge,
-                    fontWeight = FontWeight.SemiBold
-                )
-                Text(
-                    cloudTts.errorMessage
-                        ?: cloudTts.progress.currentPositionLabel
-                        ?: cloudTts.statusMessage
-                        ?: voice?.let { "${it.name}: ${it.description}" }
-                        ?: "",
-                    style = MaterialTheme.typography.labelSmall,
-                    color = if (cloudTts.errorMessage != null) MaterialTheme.colorScheme.error else MaterialTheme.colorScheme.onSurfaceVariant,
-                    maxLines = 1,
-                    overflow = TextOverflow.Ellipsis
-                )
-            }
-            if (showCredits) {
-                AssistChip(onClick = {}, label = { Text(readerString("credits_count", "%1\$d credits", credits)) })
-            }
-            if (cloudTts.isPlaying || cloudTts.isPaused) {
-                TextButton(onClick = onPauseResume) {
-                    Text(if (cloudTts.isPaused) readerString("tooltip_tts_resume", "Resume") else readerString("tooltip_tts_pause", "Pause"))
-                }
-            }
-            TextButton(
-                enabled = sanitized.isCloudTtsAvailable || ttsBusy,
-                onClick = { if (ttsBusy) onStop() else onRead() }
-            ) {
-                Text(if (ttsBusy) readerString("action_stop", "Stop") else readerString("action_read", "Read"))
-            }
-            IconButton(onClick = onOpenSettings) {
-                Icon(Icons.Default.Settings, contentDescription = readerString("desktop_cloud_tts_settings", "Cloud TTS settings"))
-            }
-        }
-    }
-}
-
-@Composable
-internal fun DesktopCloudTtsSettingsOverlay(
-    settings: ReaderAiByokSettings,
-    isTtsActive: Boolean,
-    showCredits: Boolean,
-    credits: Int,
-    cacheSummary: ReaderTtsCacheSummary = ReaderTtsCacheSummary(),
-    onClearCache: (() -> Unit)? = null,
-    onSettingsChange: (ReaderAiByokSettings) -> Unit
-) {
-    val sanitized = settings.sanitized()
-    Surface(
-        color = MaterialTheme.colorScheme.surface,
-        contentColor = MaterialTheme.colorScheme.onSurface,
-        shape = RoundedCornerShape(8.dp),
-        tonalElevation = 4.dp,
-        shadowElevation = 8.dp
-    ) {
-        Column(
-            modifier = Modifier.fillMaxWidth().padding(12.dp),
-            verticalArrangement = Arrangement.spacedBy(10.dp)
-        ) {
-            Row(verticalAlignment = Alignment.CenterVertically) {
-                Column(modifier = Modifier.weight(1f)) {
-                    Text(readerString("desktop_cloud_tts_voice", "Cloud TTS voice"), style = MaterialTheme.typography.titleSmall, fontWeight = FontWeight.SemiBold)
-                    Text(
-                        if (isTtsActive) {
-                            readerString("desktop_stop_reading_change_voices", "Stop reading to change voices.")
-                        } else {
-                            readerString("desktop_choose_cloud_tts_voice", "Choose the Gemini voice used for cloud read aloud.")
-                        },
-                        style = MaterialTheme.typography.bodySmall,
-                        color = MaterialTheme.colorScheme.onSurfaceVariant
-                    )
-                }
-                if (showCredits) {
-                    Surface(
-                        color = MaterialTheme.colorScheme.tertiaryContainer,
-                        shape = RoundedCornerShape(10.dp)
-                    ) {
-                        Text(
-                            readerString("credits_count", "%1\$d credits", credits),
-                            modifier = Modifier.padding(horizontal = 8.dp, vertical = 4.dp),
-                            style = MaterialTheme.typography.labelSmall,
-                            fontWeight = FontWeight.Bold,
-                            color = MaterialTheme.colorScheme.onTertiaryContainer
-                        )
-                    }
-                }
-            }
-            Row(
-                modifier = Modifier.fillMaxWidth().horizontalScroll(rememberScrollState()),
-                horizontalArrangement = Arrangement.spacedBy(6.dp)
-            ) {
-                ReaderCloudTtsVoices.forEach { voice ->
-                    FilterChip(
-                        selected = sanitized.ttsSpeakerId == voice.id,
-                        enabled = !isTtsActive,
-                        onClick = { onSettingsChange(sanitized.copy(ttsSpeakerId = voice.id)) },
-                        label = {
-                            Column {
-                                Text(voice.name, maxLines = 1, overflow = TextOverflow.Ellipsis)
-                                Text(
-                                    voice.description,
-                                    style = MaterialTheme.typography.labelSmall,
-                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                                    maxLines = 1,
-                                    overflow = TextOverflow.Ellipsis
-                                )
-                            }
-                        }
-                    )
-                }
-            }
-            if (cacheSummary.hasCachedAudio) {
-                HorizontalDivider()
-                Row(modifier = Modifier.fillMaxWidth(), verticalAlignment = Alignment.CenterVertically) {
-                    Column(modifier = Modifier.weight(1f)) {
-                        Text(readerString("desktop_voice_cache", "Voice cache"), style = MaterialTheme.typography.titleSmall, fontWeight = FontWeight.SemiBold)
-                        Text(
-                            cacheSummary.currentVoiceLabel,
-                            style = MaterialTheme.typography.bodySmall,
-                            color = MaterialTheme.colorScheme.onSurfaceVariant
-                        )
-                    }
-                    if (cacheSummary.hasCurrentVoiceCachedAudio && onClearCache != null) {
-                        TextButton(enabled = !isTtsActive, onClick = onClearCache) {
-                            Text(readerString("desktop_clear_voice_cache", "Clear voice cache"))
-                        }
-                    }
-                }
-            }
-        }
-    }
-}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopAppHost.kt

@@ -38,7 +38,6 @@ import androidx.compose.ui.window.application
 import androidx.compose.ui.window.rememberWindowState
 import com.aryan.reader.shared.AppContrastOption
 import com.aryan.reader.shared.AppThemeMode
-import com.aryan.reader.shared.ReaderFeatureSurface
 import com.aryan.reader.shared.ui.SharedAppTheme
 import com.aryan.reader.shared.ui.readerString
 import kotlinx.coroutines.Dispatchers
@@ -58,6 +57,8 @@ import java.util.concurrent.atomic.AtomicReference
 
 internal val DesktopDefaultAppSeedColor = Color(0xFFFFB300)
 
+private val DesktopReaderWindowFullscreenExitFocusRetryDelaysMillis = longArrayOf(160L, 200L)
+
 internal fun launchEpistemeDesktopApplication(startupSplash: DesktopStartupSplash? = null) {
     configureComposeSwingInterop()
     application {
@@ -190,35 +191,69 @@ internal const val ComposeInteropBlendingProperty = "compose.interop.blending"
 internal const val ComposeInteropBlendingEnabled = "true"
 private const val DesktopWindowStatePersistDebounceMillis = 450L
 
-internal fun configureComposeSwingInterop() {
-    // Must run before Compose creates the desktop window. Vertical EPUB embeds a Swing-backed
-    // JCEF WebView, and current Compose interop can leave a stale black native rectangle after
-    // that reader surface is removed unless interop blending is enabled.
-    if (System.getProperty(ComposeInteropBlendingProperty).isNullOrBlank()) {
-        System.setProperty(ComposeInteropBlendingProperty, ComposeInteropBlendingEnabled)
+internal fun composeInteropBlendingDefault(
+    platform: DesktopPlatform = currentDesktopPlatform()
+): String? {
+    return if (desktopEpubWebViewUsesNativeSwtBrowser(platform)) {
+        null
+    } else {
+        ComposeInteropBlendingEnabled
     }
 }
 
+internal fun configureComposeSwingInterop(
+    platform: DesktopPlatform = currentDesktopPlatform()
+) {
+    // Must run before Compose creates the desktop window. Vertical EPUB embeds native SWT/AWT
+    // browser surfaces; the blending path can prevent those native children from painting.
+    if (System.getProperty(ComposeInteropBlendingProperty).isNullOrBlank()) {
+        composeInteropBlendingDefault(platform)?.let { defaultValue ->
+            System.setProperty(ComposeInteropBlendingProperty, defaultValue)
+        }
+    }
+    logDesktopWebView2(
+        "compose_interop platform=${platform.os} blending=${System.getProperty(ComposeInteropBlendingProperty).orEmpty().ifBlank { "default" }}"
+    )
+}
+
 @Composable
-private fun DesktopWindowStatePersistenceEffect(
+internal fun DesktopWindowStatePersistenceEffect(
     windowState: WindowState,
     store: DesktopWindowStateStore,
-    enabled: Boolean
+    enabled: Boolean,
+    transformSnapshot: (DesktopWindowStateSnapshot) -> DesktopWindowStateSnapshot? = { it },
+    onSnapshotSaved: (DesktopWindowStateSnapshot) -> Unit = {}
 ) {
     val persistenceEnabled by rememberUpdatedState(enabled)
+    val latestTransformSnapshot by rememberUpdatedState(transformSnapshot)
+    val latestOnSnapshotSaved by rememberUpdatedState(onSnapshotSaved)
     LaunchedEffect(windowState, store) {
         snapshotFlow { DesktopWindowStateSnapshot.fromWindowState(windowState) }
             .distinctUntilChanged()
             .collectLatest { snapshot ->
                 if (!persistenceEnabled || snapshot == null) return@collectLatest
+                val persistableSnapshot = latestTransformSnapshot(snapshot) ?: return@collectLatest
                 delay(DesktopWindowStatePersistDebounceMillis)
                 if (persistenceEnabled) {
                     withContext(Dispatchers.IO) {
-                        store.save(snapshot)
+                        store.save(persistableSnapshot)
                     }
+                    latestOnSnapshotSaved(persistableSnapshot)
                 }
             }
     }
+    DisposableEffect(windowState, store) {
+        onDispose {
+            if (persistenceEnabled) {
+                DesktopWindowStateSnapshot.fromWindowState(windowState)
+                    ?.let(latestTransformSnapshot)
+                    ?.let { snapshot ->
+                        runCatching { store.save(snapshot) }
+                        latestOnSnapshotSaved(snapshot)
+                    }
+            }
+        }
+    }
 }
 
 @Composable
@@ -259,6 +294,14 @@ internal fun DesktopReaderFullscreenEffect(
             }
             awtWindow.refreshDesktopReaderWindowFocus()
         }
+        if (!enabled) {
+            for (delayMillis in DesktopReaderWindowFullscreenExitFocusRetryDelaysMillis) {
+                delay(delayMillis)
+                EventQueue.invokeLater {
+                    awtWindow.refreshDesktopReaderWindowFocus()
+                }
+            }
+        }
     }
 
     DisposableEffect(awtWindow) {
@@ -444,16 +487,43 @@ private fun java.awt.Window.refreshDesktopReaderWindowFocus() {
 internal fun DesktopReaderFullscreenKeyEffect(
     enabled: Boolean,
     onKeyPressed: (AwtKeyEvent) -> Boolean
+) {
+    DesktopReaderKeyDispatcherEffect(
+        enabled = enabled,
+        allowChromeModalWindows = false,
+        onKeyPressed = onKeyPressed
+    )
+}
+
+@Composable
+internal fun DesktopReaderKeyDispatcherEffect(
+    enabled: Boolean,
+    allowChromeModalWindows: Boolean = false,
+    allowPanelModalWindows: Boolean = false,
+    dispatchWhenOwnerWindowActive: Boolean = true,
+    onKeyPressed: (AwtKeyEvent) -> Boolean
 ) {
     val currentOnKeyPressed by rememberUpdatedState(onKeyPressed)
-    DisposableEffect(enabled) {
+    DisposableEffect(
+        enabled,
+        allowChromeModalWindows,
+        allowPanelModalWindows,
+        dispatchWhenOwnerWindowActive
+    ) {
         if (!enabled) {
             onDispose {}
         } else {
             val focusManager = KeyboardFocusManager.getCurrentKeyboardFocusManager()
             val dispatcher = java.awt.KeyEventDispatcher { event ->
-                val modalWindowActive = focusManager.activeWindow?.isDesktopReaderModalWindow() == true
-                !modalWindowActive && event.id == AwtKeyEvent.KEY_PRESSED && currentOnKeyPressed(event)
+                val keyWindow = focusManager.focusedWindow ?: focusManager.activeWindow
+                val activeReaderModalKind = keyWindow?.desktopReaderModalWindowKind()
+                val activeWindowAllowed = desktopReaderKeyDispatchAllowedForActiveWindowKind(
+                    activeReaderModalKind = activeReaderModalKind,
+                    allowChromeModalWindows = allowChromeModalWindows,
+                    allowPanelModalWindows = allowPanelModalWindows,
+                    dispatchWhenOwnerWindowActive = dispatchWhenOwnerWindowActive
+                )
+                activeWindowAllowed && event.id == AwtKeyEvent.KEY_PRESSED && currentOnKeyPressed(event)
             }
             focusManager.addKeyEventDispatcher(dispatcher)
             onDispose {
@@ -463,18 +533,62 @@ internal fun DesktopReaderFullscreenKeyEffect(
     }
 }
 
-private fun java.awt.Window.isDesktopReaderModalWindow(): Boolean {
+internal enum class DesktopReaderModalWindowKind {
+    CHROME,
+    PANEL,
+    POPUP
+}
+
+internal fun desktopReaderKeyDispatchAllowedForActiveWindowKind(
+    activeReaderModalKind: DesktopReaderModalWindowKind?,
+    allowChromeModalWindows: Boolean,
+    allowPanelModalWindows: Boolean,
+    dispatchWhenOwnerWindowActive: Boolean
+): Boolean {
+    return when (activeReaderModalKind) {
+        null -> dispatchWhenOwnerWindowActive
+        DesktopReaderModalWindowKind.CHROME -> allowChromeModalWindows
+        DesktopReaderModalWindowKind.PANEL -> allowPanelModalWindows
+        DesktopReaderModalWindowKind.POPUP -> false
+    }
+}
+
+private fun java.awt.Window.desktopReaderModalWindowKind(): DesktopReaderModalWindowKind? {
     val windowTitle = when (this) {
         is java.awt.Dialog -> title
         is Frame -> title
         else -> ""
     }
-    return name?.startsWith(DesktopReaderModalWindowNamePrefix) == true ||
-        windowTitle.startsWith("Reader Panel") ||
-        windowTitle.startsWith("Reader Popup")
+    return desktopReaderModalWindowKind(
+        windowName = name.orEmpty(),
+        windowTitle = windowTitle
+    )
 }
 
-private const val DesktopReaderModalWindowNamePrefix = "shared-reader-modal:"
+internal fun desktopReaderModalWindowKind(
+    windowName: String,
+    windowTitle: String
+): DesktopReaderModalWindowKind? {
+    return when {
+        windowName == "${DesktopReaderModalWindowNamePrefix}ChromeTop" ||
+            windowName == "${DesktopReaderModalWindowNamePrefix}ChromeBottom" ||
+            windowTitle.startsWith("Reader Chrome") -> DesktopReaderModalWindowKind.CHROME
+
+        windowName == "${DesktopReaderModalWindowNamePrefix}Panel" ||
+            windowName == "${DesktopReaderModalWindowNamePrefix}PanelLeft" ||
+            windowName == "${DesktopReaderModalWindowNamePrefix}PanelRight" ||
+            windowTitle.startsWith("Reader Panel") ||
+            windowTitle.startsWith("Reader Navigation") ||
+            windowTitle.startsWith("Reader Tools") -> DesktopReaderModalWindowKind.PANEL
+
+        windowName.startsWith(DesktopReaderModalWindowNamePrefix) ||
+            windowTitle.startsWith("Reader Popup") -> DesktopReaderModalWindowKind.POPUP
+
+        else -> null
+    }
+}
+
+internal const val DesktopReaderModalWindowNamePrefix = "shared-reader-modal:"
 
 internal data class DesktopWebViewRuntimeState(
     val initialized: Boolean = false,
@@ -483,15 +597,43 @@ internal data class DesktopWebViewRuntimeState(
     val errorMessage: String? = null
 )
 
-internal fun shouldRequestDesktopWebViewRuntime(readerSurface: ReaderFeatureSurface?): Boolean {
-    return readerSurface == ReaderFeatureSurface.TEXT_READER
+internal enum class DesktopEpubWebViewBackend(
+    val logName: String,
+    val displayName: String
+) {
+    WINDOWS_WEBVIEW2("webview2", "Microsoft Edge WebView2"),
+    WEBKIT("webkit", "WebKit"),
+    UNSUPPORTED("unsupported", "native webview")
 }
 
-internal fun shouldStartDesktopWebViewRuntime(
-    requested: Boolean,
-    state: DesktopWebViewRuntimeState
+internal fun desktopEpubWebViewBackend(
+    platform: DesktopPlatform = currentDesktopPlatform()
+): DesktopEpubWebViewBackend {
+    return when (platform.os) {
+        DesktopOperatingSystem.WINDOWS -> DesktopEpubWebViewBackend.WINDOWS_WEBVIEW2
+        DesktopOperatingSystem.LINUX,
+        DesktopOperatingSystem.MACOS -> DesktopEpubWebViewBackend.WEBKIT
+        DesktopOperatingSystem.OTHER -> DesktopEpubWebViewBackend.UNSUPPORTED
+    }
+}
+
+internal fun desktopEpubWebViewUsesNativeSwtBrowser(
+    platform: DesktopPlatform = currentDesktopPlatform()
 ): Boolean {
-    return requested && !state.initialized && !state.restartRequired && state.errorMessage == null
+    return desktopEpubWebViewBackend(platform) != DesktopEpubWebViewBackend.UNSUPPORTED
+}
+
+internal fun desktopEpubWebViewUsesWebView2(
+    platform: DesktopPlatform = currentDesktopPlatform()
+): Boolean {
+    return desktopEpubWebViewBackend(platform) == DesktopEpubWebViewBackend.WINDOWS_WEBVIEW2
+}
+
+internal fun desktopEpubWebViewCanRender(
+    state: DesktopWebViewRuntimeState,
+    platform: DesktopPlatform = currentDesktopPlatform()
+): Boolean {
+    return desktopEpubWebViewUsesNativeSwtBrowser(platform)
 }
 
 @Composable
@@ -499,7 +641,10 @@ internal fun DesktopWebViewRuntimeIndicator(
     state: DesktopWebViewRuntimeState,
     modifier: Modifier = Modifier
 ) {
+    val platform = currentDesktopPlatform()
     val message = when {
+        !desktopEpubWebViewUsesNativeSwtBrowser(platform) ->
+            readerString("desktop_webview_unsupported", "Embedded webview is unavailable on this desktop platform.")
         state.errorMessage != null -> readerString("desktop_webview_start_error", "Embedded webview could not start: %1\$s", state.errorMessage)
         state.restartRequired -> readerString("desktop_webview_restart_required", "Embedded webview installed. Restart Episteme to finish setup.")
         state.downloadProgress >= 0f -> readerString("desktop_webview_preparing_progress", "Preparing bundled embedded webview %1\$d%%", state.downloadProgress.toInt())
@@ -515,7 +660,9 @@ internal fun DesktopWebViewRuntimeIndicator(
             verticalArrangement = Arrangement.spacedBy(12.dp)
         ) {
             if (state.errorMessage == null && !state.restartRequired) {
-                CircularProgressIndicator()
+                if (desktopEpubWebViewUsesNativeSwtBrowser(platform)) {
+                    CircularProgressIndicator()
+                }
             }
             Text(
                 text = message,

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopAppState.kt

@@ -7,8 +7,12 @@ import com.aryan.reader.shared.SharedLibrarySnapshot
 import com.aryan.reader.shared.SharedLibraryStateProjector
 import com.aryan.reader.shared.SharedReaderScreenState
 import com.aryan.reader.shared.ShelfRecord
+import com.aryan.reader.shared.reader.ReaderSettings
 import com.aryan.reader.shared.reader.SharedEpubBook
 import com.aryan.reader.shared.reader.SharedEpubChapter
+import com.aryan.reader.shared.ui.SharedAppTab
+
+internal val DesktopInitialAppTab = SharedAppTab.LIBRARY
 
 internal fun desktopEmptyReaderBook(): SharedEpubBook {
     val noBookOpen = loadDesktopStringResolver().string("desktop_no_book_open", "No book open")
@@ -27,11 +31,37 @@ internal fun desktopEmptyReaderBook(): SharedEpubBook {
 }
 
 internal fun SharedLibrarySnapshot.withDesktopDefaults(): SharedLibrarySnapshot {
-    return if (appSeedColor == null) {
-        copy(appSeedColor = DesktopDefaultAppSeedColor)
+    val shouldMigrateReaderDefaults = desktopReaderDefaultsVersion < DesktopReaderDefaultsVersion
+    val migratedTextDefaults = if (shouldMigrateReaderDefaults && readerDefaultSettings == ReaderSettings()) {
+        DesktopDefaultTextReaderSettings
     } else {
-        this
+        readerDefaultSettings
     }
+    val migratedPdfDefaults = if (shouldMigrateReaderDefaults && pdfReaderDefaultSettings == ReaderSettings(themeId = "no_theme")) {
+        DesktopDefaultPdfReaderSettings
+    } else {
+        pdfReaderDefaultSettings
+    }
+    val migratedBooks = if (shouldMigrateReaderDefaults) {
+        books.map { book ->
+            when {
+                book.usesDesktopReaderSettingsEngine(DesktopReaderSettingsEngine.TEXT) &&
+                    book.readerSettings == ReaderSettings() -> book.copy(readerSettings = migratedTextDefaults)
+                book.usesDesktopReaderSettingsEngine(DesktopReaderSettingsEngine.PDF) &&
+                    book.readerSettings == ReaderSettings(themeId = "no_theme") -> book.copy(readerSettings = migratedPdfDefaults)
+                else -> book
+            }
+        }
+    } else {
+        books
+    }
+    return copy(
+        books = migratedBooks,
+        appSeedColor = appSeedColor ?: DesktopDefaultAppSeedColor,
+        readerDefaultSettings = migratedTextDefaults,
+        pdfReaderDefaultSettings = migratedPdfDefaults,
+        desktopReaderDefaultsVersion = DesktopReaderDefaultsVersion
+    )
 }
 
 internal fun SharedLibrarySnapshot.toDesktopReaderScreenState(): SharedReaderScreenState {
@@ -54,6 +84,7 @@ internal fun SharedLibrarySnapshot.toDesktopReaderScreenState(): SharedReaderScr
         appSeedColor = appSeedColor,
         appFontPreference = appFontPreference,
         customAppThemes = customAppThemes,
+        customReaderThemes = customReaderThemes,
         readerDefaultSettings = readerDefaultSettings,
         pdfReaderDefaultSettings = pdfReaderDefaultSettings,
         readerToolbarPreferences = readerToolbarPreferences,
@@ -116,8 +147,10 @@ internal fun SharedReaderScreenState.toDesktopLibrarySnapshot(
         appSeedColor = appSeedColor,
         appFontPreference = appFontPreference,
         customAppThemes = customAppThemes,
+        customReaderThemes = customReaderThemes,
         readerDefaultSettings = readerDefaultSettings,
         pdfReaderDefaultSettings = pdfReaderDefaultSettings,
+        desktopReaderDefaultsVersion = DesktopReaderDefaultsVersion,
         readerToolbarPreferences = readerToolbarPreferences,
         readerHighlightPalette = readerHighlightPalette,
         pdfHighlighterPalette = pdfHighlighterPalette,

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopAtomicFile.kt

@@ -0,0 +1,56 @@
+package com.aryan.reader.desktop
+
+import java.io.File
+import java.nio.file.AtomicMoveNotSupportedException
+import java.nio.file.Files
+import java.nio.file.StandardCopyOption
+import java.util.Properties
+
+internal fun File.writeTextAtomically(text: String) {
+    parentFile?.mkdirs()
+    val temp = createSiblingTempFile()
+    try {
+        temp.writeText(text)
+        moveReplacing(temp, this)
+    } finally {
+        runCatching { if (temp.exists()) temp.delete() }
+    }
+}
+
+internal fun File.storePropertiesAtomically(properties: Properties, comments: String) {
+    parentFile?.mkdirs()
+    val temp = createSiblingTempFile()
+    try {
+        temp.outputStream().use { output ->
+            properties.store(output, comments)
+        }
+        moveReplacing(temp, this)
+    } finally {
+        runCatching { if (temp.exists()) temp.delete() }
+    }
+}
+
+private fun File.createSiblingTempFile(): File {
+    val directory = parentFile ?: File(".")
+    directory.mkdirs()
+    val prefix = ".$name."
+    return Files.createTempFile(directory.toPath(), prefix, ".tmp").toFile()
+}
+
+private fun moveReplacing(source: File, target: File) {
+    target.parentFile?.mkdirs()
+    try {
+        Files.move(
+            source.toPath(),
+            target.toPath(),
+            StandardCopyOption.REPLACE_EXISTING,
+            StandardCopyOption.ATOMIC_MOVE
+        )
+    } catch (_: AtomicMoveNotSupportedException) {
+        Files.move(
+            source.toPath(),
+            target.toPath(),
+            StandardCopyOption.REPLACE_EXISTING
+        )
+    }
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopBuildProfile.kt

@@ -2,7 +2,9 @@ package com.aryan.reader.desktop
 
 import com.aryan.reader.shared.ReaderAiByokSettings
 import com.aryan.reader.shared.SharedFeaturePolicy
-import java.io.File
+import com.aryan.reader.shared.SharedLegalLinks
+import com.aryan.reader.shared.SharedLegalProfile
+import com.aryan.reader.shared.sharedLegalLinksForProfile
 
 internal const val DesktopFlavorProperty = "episteme.desktop.flavor"
 internal const val DesktopVersionProperty = "episteme.desktop.version"
@@ -16,10 +18,21 @@ internal data class DesktopBuildProfile(
     val flavor: String,
     val appName: String,
     val buildLabel: String,
-    val featurePolicy: SharedFeaturePolicy
+    val featurePolicy: SharedFeaturePolicy,
+    val legalProfile: SharedLegalProfile = if (featurePolicy.byokAi) {
+        SharedLegalProfile.OSS
+    } else {
+        SharedLegalProfile.STANDARD
+    }
 ) {
     val isOssOffline: Boolean get() = flavor == DesktopFlavorOssOffline
+    val aiKeySettingsAvailable: Boolean
+        get() = featurePolicy.aiAndCloud && featurePolicy.networkAccess && legalProfile != SharedLegalProfile.OSS
     val byokAiAvailable: Boolean get() = featurePolicy.byokAi && featurePolicy.aiAndCloud && featurePolicy.networkAccess
+    val creditBackedCloudTtsControlsAvailable: Boolean
+        get() = featurePolicy.aiAndCloud && featurePolicy.networkAccess && !byokAiAvailable
+    val legalLinks: SharedLegalLinks
+        get() = sharedLegalLinksForProfile(legalProfile)
 }
 
 internal fun currentDesktopBuildProfile(): DesktopBuildProfile {
@@ -35,13 +48,15 @@ internal fun desktopBuildProfileForFlavor(rawFlavor: String?): DesktopBuildProfi
             flavor = DesktopFlavorOssOffline,
             appName = EpistemeDesktopOssAppName,
             buildLabel = "Offline OSS edition",
-            featurePolicy = SharedFeaturePolicy.OssOffline
+            featurePolicy = SharedFeaturePolicy.OssOffline,
+            legalProfile = SharedLegalProfile.OSS
         )
         else -> DesktopBuildProfile(
             flavor = DesktopFlavorStandard,
             appName = EpistemeDesktopStandardAppName,
             buildLabel = "Standard edition",
-            featurePolicy = SharedFeaturePolicy.Standard
+            featurePolicy = SharedFeaturePolicy.Standard,
+            legalProfile = SharedLegalProfile.STANDARD
         )
     }
 }
@@ -59,48 +74,12 @@ internal fun ReaderAiByokSettings.withDesktopFeaturePolicy(
     featurePolicy: SharedFeaturePolicy
 ): ReaderAiByokSettings {
     return if (featurePolicy.byokAi && featurePolicy.aiAndCloud && featurePolicy.networkAccess) {
-        sanitized()
+        toDesktopPersistableAiSettings()
     } else {
-        ReaderAiByokSettings(hideReaderAiFeatures = true)
+        ReaderAiByokSettings()
     }
 }
 
-internal fun bundledDesktopWebViewDir(): File {
-    val platform = currentDesktopPlatform()
-    val resourceDir = System.getProperty(ComposeApplicationResourcesDirProperty)
-        ?.takeIf { it.isNotBlank() }
-        ?.let(::File)
-    return listOfNotNull(
-        resourceDir?.resolve("kcef-bundle"),
-        File(System.getProperty("user.dir"), "kcef-bundle"),
-        File(System.getProperty("user.dir"), "desktopApp/${platform.kcefBundleDirectoryName}"),
-        File(System.getProperty("user.dir"), "desktopApp/kcef-bundle"),
-        File("desktopApp/${platform.kcefBundleDirectoryName}"),
-        File("desktopApp/kcef-bundle"),
-        File(platform.kcefBundleDirectoryName),
-        File("kcef-bundle")
-    ).firstOrNull(::isBundledDesktopWebViewPresent)
-        ?: resourceDir?.resolve("kcef-bundle")
-        ?: File(platform.kcefBundleDirectoryName)
-}
-
-internal fun isBundledDesktopWebViewPresent(
-    dir: File,
-    platform: DesktopPlatform = currentDesktopPlatform()
-): Boolean {
-    return dir.isDirectory &&
-        bundledDesktopWebViewRequiredPaths(platform).all { requiredPath ->
-            dir.resolve(requiredPath).exists()
-        }
-}
-
-internal fun bundledDesktopWebViewRequiredPaths(
-    platform: DesktopPlatform = currentDesktopPlatform()
-): List<String> {
-    return when (platform.os) {
-        DesktopOperatingSystem.WINDOWS -> listOf("jcef.dll", "libcef.dll")
-        DesktopOperatingSystem.LINUX -> listOf("libcef.so", "chrome-sandbox", "icudtl.dat", "locales")
-        DesktopOperatingSystem.MACOS -> listOf("jcef Helper.app", "Chromium Embedded Framework.framework")
-        DesktopOperatingSystem.OTHER -> emptyList()
-    }
+internal fun ReaderAiByokSettings.toDesktopPersistableAiSettings(): ReaderAiByokSettings {
+    return sanitized().copy(hideReaderAiFeatures = false)
 }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopCloudConfig.kt

@@ -21,7 +21,14 @@ internal data class DesktopCloudConfig(
 }
 
 internal fun loadDesktopCloudConfig(): DesktopCloudConfig {
-    val resourceProperties = Properties().apply {
+    return desktopCloudConfigFromProperties(
+        resourceProperties = loadDesktopCloudResourceProperties(),
+        localProperties = loadDesktopLocalProperties()
+    )
+}
+
+private fun loadDesktopCloudResourceProperties(): Properties {
+    return Properties().apply {
         val classLoader = DesktopCloudConfig::class.java.classLoader
         val stream = classLoader.getResourceAsStream("desktop-cloud.properties")
             ?: classLoader.getResourceAsStream("common/desktop-cloud.properties")
@@ -35,18 +42,27 @@ internal fun loadDesktopCloudConfig(): DesktopCloudConfig {
                 }
         stream?.use { input -> load(input) }
     }
-    val localProperties = Properties().apply {
-        File("local.properties")
-            .takeIf { it.isFile }
+}
+
+private fun loadDesktopLocalProperties(file: File = File("local.properties")): Properties {
+    return Properties().apply {
+        file.takeIf { it.isFile }
             ?.inputStream()
             ?.use { input -> load(input) }
     }
+}
 
+internal fun desktopCloudConfigFromProperties(
+    resourceProperties: Properties,
+    localProperties: Properties = Properties(),
+    systemProperty: (String) -> String? = { key -> System.getProperty("episteme.desktop.$key") },
+    environment: (String) -> String? = { key -> System.getenv(key) }
+): DesktopCloudConfig {
     fun value(vararg keys: String): String {
         return keys.firstNotNullOfOrNull { key ->
-            System.getProperty("episteme.desktop.$key")
-                ?: System.getenv("EPISTEME_DESKTOP_${key.uppercase()}")
-                ?: System.getenv(key)
+            systemProperty(key)
+                ?: environment("EPISTEME_DESKTOP_${key.uppercase()}")
+                ?: environment(key)
                 ?: localProperties.getProperty("DESKTOP_$key")
                 ?: localProperties.getProperty(key)
                 ?: resourceProperties.getProperty(key)
@@ -56,7 +72,7 @@ internal fun loadDesktopCloudConfig(): DesktopCloudConfig {
     val aiWorkerUrl = value("AI_WORKER_URL").ifBlank {
         "https://reader-ai.aryanrajttps.workers.dev"
     }
-    val ttsWorkerUrl = value("TTS_WORKER_URL").ifBlank { aiWorkerUrl }
+    val ttsWorkerUrl = value("TTS_WORKER_URL")
 
     return DesktopCloudConfig(
         aiWorkerUrl = aiWorkerUrl,

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopCloudRepositories.kt

@@ -32,6 +32,7 @@ import java.net.http.HttpResponse
 import java.nio.file.Files
 import java.nio.file.StandardCopyOption
 import java.time.Duration
+import java.time.Instant
 import java.util.Collections
 import java.util.UUID
 
@@ -50,6 +51,8 @@ internal data class DesktopCloudBookMetadata(
     val isRecent: Boolean = true,
     val isDeleted: Boolean = false,
     val lastModifiedTimestamp: Long = 0L,
+    val readingPositionModifiedTimestamp: Long = 0L,
+    val annotationModifiedTimestamp: Long = 0L,
     val bookmarksJson: String? = null,
     val hasAnnotations: Boolean = false,
     val fileContentModifiedTimestamp: Long = 0L,
@@ -83,7 +86,8 @@ internal data class DesktopCloudFontMetadata(
 
 internal data class DesktopDriveFile(
     val id: String,
-    val name: String
+    val name: String,
+    val modifiedTimeMillis: Long = 0L
 )
 
 internal class DesktopFirestoreRepository(
@@ -266,6 +270,10 @@ internal class DesktopGoogleDriveRepository(
         listFiles(accessToken = accessToken, query = null)
     }
 
+    suspend fun getFileByName(accessToken: String, fileName: String): DesktopDriveFile? = withContext(Dispatchers.IO) {
+        listFiles(accessToken, "name = '${driveQueryStringValue(fileName)}' and trashed = false").firstOrNull()
+    }
+
     suspend fun uploadFont(accessToken: String, fileName: String, file: File, extension: String): DesktopDriveFile? =
         uploadNamedFile(
             accessToken = accessToken,
@@ -293,18 +301,20 @@ internal class DesktopGoogleDriveRepository(
     suspend fun uploadAnnotationFile(accessToken: String, bookId: String, file: File): DesktopDriveFile? {
         return uploadNamedFile(
             accessToken = accessToken,
-            fileName = "annotation_$bookId.json",
+            fileName = desktopCloudAnnotationDriveFileName(bookId),
             file = file,
             contentType = "application/json"
         )
     }
 
     suspend fun downloadAnnotationFile(accessToken: String, bookId: String, destination: File): Boolean {
-        val fileId = listFiles(accessToken, "name = '${driveQueryStringValue("annotation_$bookId.json")}' and trashed = false")
-            .firstOrNull()
-            ?.id
+        val driveFile = getFileByName(accessToken, desktopCloudAnnotationDriveFileName(bookId))
             ?: return false
-        return downloadFile(accessToken, fileId, destination)
+        return downloadFile(accessToken, driveFile.id, destination).also { downloaded ->
+            if (downloaded && driveFile.modifiedTimeMillis > 0L) {
+                destination.setLastModified(driveFile.modifiedTimeMillis)
+            }
+        }
     }
 
     suspend fun downloadFile(accessToken: String, fileId: String, destination: File): Boolean = withContext(Dispatchers.IO) {
@@ -375,9 +385,9 @@ internal class DesktopGoogleDriveRepository(
         }.toByteArray(Charsets.UTF_8)
         val suffix = "\r\n--$boundary--\r\n".toByteArray(Charsets.UTF_8)
         val uploadUri = if (existingFileId == null) {
-            URI.create("https://www.googleapis.com/upload/drive/v3/files?${query("uploadType" to "multipart", "fields" to "id,name")}")
+            URI.create("https://www.googleapis.com/upload/drive/v3/files?${query("uploadType" to "multipart", "fields" to "id,name,modifiedTime")}")
         } else {
-            URI.create("https://www.googleapis.com/upload/drive/v3/files/${pathEncode(existingFileId)}?${query("uploadType" to "multipart", "fields" to "id,name")}")
+            URI.create("https://www.googleapis.com/upload/drive/v3/files/${pathEncode(existingFileId)}?${query("uploadType" to "multipart", "fields" to "id,name,modifiedTime")}")
         }
         val request = HttpRequest.newBuilder(uploadUri)
             .timeout(Duration.ofMinutes(5))
@@ -399,14 +409,15 @@ internal class DesktopGoogleDriveRepository(
         val root = DesktopCloudJson.parseToJsonElement(response.body()).jsonObject
         DesktopDriveFile(
             id = root.string("id").orEmpty(),
-            name = root.string("name").orEmpty()
+            name = root.string("name").orEmpty(),
+            modifiedTimeMillis = parseDriveModifiedTimeMillis(root.string("modifiedTime"))
         )
     }
 
     private fun listFiles(accessToken: String, query: String?): List<DesktopDriveFile> {
         val params = buildList {
             add("spaces" to "appDataFolder")
-            add("fields" to "files(id,name)")
+            add("fields" to "files(id,name,modifiedTime)")
             if (!query.isNullOrBlank()) add("q" to query)
         }
         val request = HttpRequest.newBuilder(
@@ -426,11 +437,20 @@ internal class DesktopGoogleDriveRepository(
             val obj = element.jsonObjectOrNull() ?: return@mapNotNull null
             val id = obj.string("id") ?: return@mapNotNull null
             val name = obj.string("name") ?: return@mapNotNull null
-            DesktopDriveFile(id = id, name = name)
+            DesktopDriveFile(
+                id = id,
+                name = name,
+                modifiedTimeMillis = parseDriveModifiedTimeMillis(obj.string("modifiedTime"))
+            )
         }
     }
 }
 
+private fun parseDriveModifiedTimeMillis(value: String?): Long {
+    if (value.isNullOrBlank()) return 0L
+    return runCatching { Instant.parse(value).toEpochMilli() }.getOrDefault(0L)
+}
+
 private data class DesktopFirestoreDocument(
     val id: String,
     val fields: JsonObject?
@@ -464,6 +484,8 @@ private fun DesktopCloudBookMetadata.toFirestoreFields(): Map<String, JsonElemen
     "isRecent" to firestoreBoolean(isRecent),
     "isDeleted" to firestoreBoolean(isDeleted),
     "lastModifiedTimestamp" to firestoreLong(lastModifiedTimestamp),
+    "readingPositionModifiedTimestamp" to firestoreLong(readingPositionModifiedTimestamp),
+    "annotationModifiedTimestamp" to firestoreLong(annotationModifiedTimestamp),
     "bookmarksJson" to firestoreNullableString(bookmarksJson),
     "hasAnnotations" to firestoreBoolean(hasAnnotations),
     "fileContentModifiedTimestamp" to firestoreLong(fileContentModifiedTimestamp),
@@ -512,6 +534,8 @@ private fun JsonObject.toBookMetadata(documentId: String): DesktopCloudBookMetad
         isRecent = booleanField("isRecent") ?: true,
         isDeleted = booleanField("isDeleted") ?: false,
         lastModifiedTimestamp = longField("lastModifiedTimestamp"),
+        readingPositionModifiedTimestamp = longField("readingPositionModifiedTimestamp"),
+        annotationModifiedTimestamp = longField("annotationModifiedTimestamp"),
         bookmarksJson = stringField("bookmarksJson"),
         hasAnnotations = booleanField("hasAnnotations") ?: false,
         fileContentModifiedTimestamp = longField("fileContentModifiedTimestamp"),

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopCloudSidecarSync.kt

@@ -11,54 +11,118 @@ import kotlinx.serialization.json.JsonElement
 import kotlinx.serialization.json.JsonNull
 import kotlinx.serialization.json.JsonObject
 import kotlinx.serialization.json.JsonPrimitive
-import kotlinx.serialization.json.contentOrNull
 import kotlinx.serialization.json.jsonObject
-import kotlinx.serialization.json.jsonPrimitive
 import java.io.File
 
 internal object DesktopCloudSidecarSync {
+    fun localAnnotationDebugSummary(book: BookItem): String {
+        val path = book.path?.takeIf { it.isNotBlank() } ?: return "path=null type=${book.type}"
+        if (book.type != FileType.PDF) return "path=${path.logPreview(140)} type=${book.type}"
+        val annotationFile = desktopPdfAnnotationFile(path)
+        val deletedAnnotationFile = desktopPdfAnnotationDeletionFile(path)
+        val bookmarkFile = desktopPdfBookmarkFile(path)
+        val richTextFile = desktopPdfRichTextFile(path)
+        return "path=${path.logPreview(140)} " +
+            "annotations{exists=${annotationFile.isFile} syncable=${annotationFile.hasSyncablePdfAnnotations()} " +
+            "bytes=${annotationFile.length()} ts=${annotationFile.lastModifiedIfFile()}} " +
+            "deletedAnnotations{exists=${deletedAnnotationFile.isFile} count=${deletedAnnotationFile.annotationDeletionCount()} " +
+            "bytes=${deletedAnnotationFile.length()} ts=${deletedAnnotationFile.lastModifiedIfFile()}} " +
+            "bookmarks{exists=${bookmarkFile.isFile} bytes=${bookmarkFile.length()} ts=${bookmarkFile.lastModifiedIfFile()}} " +
+            "text{exists=${richTextFile.isFile} syncable=${richTextFile.hasSyncablePdfRichText()} " +
+            "bytes=${richTextFile.length()} ts=${richTextFile.lastModifiedIfFile()}} " +
+            "payloadTs=${localAnnotationPayloadTimestamp(book)} totalTs=${localAnnotationTimestamp(book)}"
+    }
+
     fun hasLocalAnnotationData(book: BookItem): Boolean {
         val path = book.path?.takeIf { it.isNotBlank() } ?: return false
         if (book.type != FileType.PDF) return false
-        return desktopPdfAnnotationFile(path).isFile ||
+        return desktopPdfAnnotationFile(path).hasSyncablePdfAnnotations() ||
+            desktopPdfAnnotationDeletionFile(path).hasSyncablePdfAnnotationDeletions() ||
             desktopPdfBookmarkFile(path).isFile ||
-            desktopPdfRichTextFile(path).isFile
+            desktopPdfRichTextFile(path).hasSyncablePdfRichText()
     }
 
     fun localAnnotationTimestamp(book: BookItem): Long {
         val path = book.path?.takeIf { it.isNotBlank() } ?: return 0L
         if (book.type != FileType.PDF) return 0L
         return maxOf(
-            desktopPdfAnnotationFile(path).lastModifiedIfFile(),
-            desktopPdfBookmarkFile(path).lastModifiedIfFile(),
-            desktopPdfRichTextFile(path).lastModifiedIfFile()
+            localAnnotationPayloadTimestamp(path),
+            desktopPdfBookmarkFile(path).lastModifiedIfFile()
         )
     }
 
+    fun localAnnotationPayloadTimestamp(book: BookItem): Long {
+        val path = book.path?.takeIf { it.isNotBlank() } ?: return 0L
+        if (book.type != FileType.PDF) return 0L
+        return localAnnotationPayloadTimestamp(path)
+    }
+
+    fun markAnnotationPayloadSynced(book: BookItem, timestamp: Long) {
+        val path = book.path?.takeIf { it.isNotBlank() } ?: return
+        if (book.type != FileType.PDF || timestamp <= 0L) return
+        listOf(desktopPdfAnnotationFile(path), desktopPdfAnnotationDeletionFile(path), desktopPdfRichTextFile(path))
+            .filter { it.isFile }
+            .forEach { it.setLastModified(timestamp) }
+    }
+
+    fun recordAnnotationDeletions(book: BookItem, annotationIds: Collection<String>) {
+        val path = book.path?.takeIf { it.isNotBlank() } ?: return
+        if (book.type != FileType.PDF) return
+        recordAnnotationDeletions(path, book.id, annotationIds)
+    }
+
+    fun recordAnnotationDeletions(documentPath: String, logBookId: String, annotationIds: Collection<String>) {
+        val ids = annotationIds.mapNotNull { it.takeIf(String::isNotBlank) }.toSet()
+        if (ids.isEmpty()) return
+        val file = desktopPdfAnnotationDeletionFile(documentPath)
+        val existing = if (file.isFile) {
+            SharedPdfAnnotationSidecarCodec.annotationDeletionsFromJson(file.readText())
+        } else {
+            emptyMap()
+        }
+        val now = System.currentTimeMillis()
+        val next = existing.toMutableMap()
+        ids.forEach { id -> next[id] = maxOf(next[id] ?: 0L, now) }
+        val nextJson = SharedPdfAnnotationSidecarCodec.annotationDeletionsJson(next)
+        if (file.isFile && file.readText() == nextJson) return
+        file.parentFile?.mkdirs()
+        file.writeText(nextJson)
+        logDesktopCloudAnnotations {
+            "desktop.local.mark_deleted_annotations book=$logBookId ids=${ids.sorted()} " +
+                "bytes=${file.length()} ts=${file.lastModified()}"
+        }
+    }
+
     fun exportAnnotationBundle(book: BookItem): File? {
         val path = book.path?.takeIf { it.isNotBlank() } ?: return null
         if (book.type != FileType.PDF) return null
         val annotationFile = desktopPdfAnnotationFile(path)
-        val bookmarkFile = desktopPdfBookmarkFile(path)
+        val deletedAnnotationFile = desktopPdfAnnotationDeletionFile(path)
         val richTextFile = desktopPdfRichTextFile(path)
+        logDesktopCloudAnnotations {
+            "desktop.export.inspect book=${book.id} ${localAnnotationDebugSummary(book)}"
+        }
         val data = buildMap {
             if (annotationFile.isFile) {
-                val annotations = SharedPdfAnnotationSerializer.decode(annotationFile.readText())
-                put(
-                    SharedPdfAnnotationSidecarCodec.KEY_PDF_ANNOTATIONS,
-                    SharedPdfAnnotationSidecarCodec.encodeAnnotationsElement(annotations)
-                )
-            }
-            if (bookmarkFile.isFile) {
-                cloudSidecarJson.parseElementOrNull(bookmarkFile.readText())?.let { put("bookmarks", it) }
-            }
-            if (richTextFile.isFile) {
-                cloudSidecarJson.parseElementOrNull(richTextFile.readText())?.let { element ->
-                    put("text", SharedPdfRichTextSerializer.encodeElement(SharedPdfRichTextSerializer.decodeElement(element)))
+                desktopPdfAnnotationElementForSync(annotationFile.readText())?.let { annotations ->
+                    put(SharedPdfAnnotationSidecarCodec.KEY_PDF_ANNOTATIONS, annotations)
                 }
             }
+            if (deletedAnnotationFile.hasSyncablePdfAnnotationDeletions()) {
+                val deletions = SharedPdfAnnotationSidecarCodec.annotationDeletionsFromJson(deletedAnnotationFile.readText())
+                put(
+                    SharedPdfAnnotationSidecarCodec.KEY_PDF_ANNOTATION_DELETIONS,
+                    SharedPdfAnnotationSidecarCodec.encodeAnnotationDeletionsElement(deletions)
+                )
+            }
+            if (richTextFile.isFile) {
+                desktopPdfRichTextElementForSync(richTextFile.readText())?.let { put("text", it) }
+            }
+        }
+        if (data.isEmpty()) {
+            logDesktopCloudAnnotations { "desktop.export.skip book=${book.id} reason=no_syncable_payload" }
+            return null
         }
-        if (data.isEmpty()) return null
         val payload = JsonObject(mapOf("version" to JsonPrimitive(2)) + data)
         val canonical = SharedPdfAnnotationSidecarCodec.canonicalizeDataJson(
             cloudSidecarJson.encodeToString(JsonElement.serializer(), payload)
@@ -69,48 +133,129 @@ internal object DesktopCloudSidecarSync {
         )
         tempFile.parentFile?.mkdirs()
         tempFile.writeText(canonical)
+        logDesktopCloudAnnotations {
+            "desktop.export.bundle_ready book=${book.id} keys=${data.keys.toList()} " +
+                "canonicalBytes=${canonical.length} fileBytes=${tempFile.length()} temp=${tempFile.name}"
+        }
         return tempFile
     }
 
     fun importAnnotationBundle(book: BookItem, rawJson: String, timestamp: Long): Boolean {
-        val path = book.path?.takeIf { it.isNotBlank() } ?: return false
-        if (book.type != FileType.PDF) return false
-        val root = cloudSidecarJson.parseElementOrNull(rawJson)?.jsonObjectOrNull() ?: return false
+        val path = book.path?.takeIf { it.isNotBlank() } ?: run {
+            logDesktopCloudAnnotations { "desktop.import.skip book=${book.id} reason=missing_path bytes=${rawJson.length}" }
+            return false
+        }
+        if (book.type != FileType.PDF) {
+            logDesktopCloudAnnotations { "desktop.import.skip book=${book.id} reason=not_pdf type=${book.type} bytes=${rawJson.length}" }
+            return false
+        }
+        val root = cloudSidecarJson.parseElementOrNull(rawJson)?.jsonObjectOrNull() ?: run {
+            logDesktopCloudAnnotations { "desktop.import.skip book=${book.id} reason=parse_failed bytes=${rawJson.length}" }
+            return false
+        }
         val data = root["data"]?.jsonObjectOrNull() ?: root
         val canonicalData = SharedPdfAnnotationSidecarCodec.withCanonicalAnnotations(data)
         val annotationFile = desktopPdfAnnotationFile(path)
+        val deletedAnnotationFile = desktopPdfAnnotationDeletionFile(path)
         val bookmarkFile = desktopPdfBookmarkFile(path)
         val richTextFile = desktopPdfRichTextFile(path)
+        logDesktopCloudAnnotations {
+            "desktop.import.inspect book=${book.id} remoteTs=$timestamp rawBytes=${rawJson.length} " +
+                "rawKeys=${data.keys.toList()} canonicalKeys=${canonicalData.keys.toList()} " +
+                localAnnotationDebugSummary(book)
+        }
 
         if (canonicalData.hasPdfAnnotationPayload()) {
             val annotations = SharedPdfAnnotationSidecarCodec.annotationsFromData(canonicalData)
-            annotationFile.parentFile?.mkdirs()
-            annotationFile.writeText(SharedPdfAnnotationSerializer.encode(annotations))
-            annotationFile.setLastModified(timestamp)
+            if (annotations.isEmpty()) {
+                if (annotationFile.isFile) {
+                    val deleted = annotationFile.delete()
+                    logDesktopCloudAnnotations { "desktop.import.delete_annotations book=${book.id} deleted=$deleted" }
+                } else {
+                    logDesktopCloudAnnotations { "desktop.import.annotations_empty book=${book.id} existing=false" }
+                }
+            } else {
+                annotationFile.parentFile?.mkdirs()
+                annotationFile.writeText(SharedPdfAnnotationSerializer.encode(annotations))
+                annotationFile.setLastModified(timestamp)
+                logDesktopCloudAnnotations {
+                    "desktop.import.write_annotations book=${book.id} count=${annotations.size} " +
+                        "bytes=${annotationFile.length()} ts=${annotationFile.lastModified()}"
+                }
+            }
         } else if (annotationFile.isFile) {
-            annotationFile.delete()
+            val deleted = annotationFile.delete()
+            logDesktopCloudAnnotations { "desktop.import.delete_annotations_missing_payload book=${book.id} deleted=$deleted" }
+        } else {
+            logDesktopCloudAnnotations { "desktop.import.no_annotation_payload book=${book.id} existing=false" }
+        }
+
+        val deletions = SharedPdfAnnotationSidecarCodec.annotationDeletionsFromData(canonicalData)
+        if (deletions.isEmpty()) {
+            if (deletedAnnotationFile.isFile) {
+                val deleted = deletedAnnotationFile.delete()
+                logDesktopCloudAnnotations { "desktop.import.delete_annotation_tombstones book=${book.id} deleted=$deleted" }
+            }
+        } else {
+            deletedAnnotationFile.parentFile?.mkdirs()
+            deletedAnnotationFile.writeText(SharedPdfAnnotationSidecarCodec.annotationDeletionsJson(deletions))
+            deletedAnnotationFile.setLastModified(timestamp)
+            logDesktopCloudAnnotations {
+                "desktop.import.write_annotation_tombstones book=${book.id} count=${deletions.size} " +
+                    "bytes=${deletedAnnotationFile.length()} ts=${deletedAnnotationFile.lastModified()}"
+            }
         }
 
         canonicalData["bookmarks"]?.let { bookmarks ->
             bookmarkFile.parentFile?.mkdirs()
             bookmarkFile.writeText(cloudSidecarJson.encodeToString(JsonElement.serializer(), bookmarks))
             bookmarkFile.setLastModified(timestamp)
-        } ?: run {
-            if (bookmarkFile.isFile) bookmarkFile.delete()
+            logDesktopCloudAnnotations {
+                "desktop.import.write_bookmarks book=${book.id} bytes=${bookmarkFile.length()} ts=${bookmarkFile.lastModified()}"
+            }
         }
 
         canonicalData["text"]?.let { richText ->
             val richDocument = SharedPdfRichTextSerializer.decodeElement(richText)
-            richTextFile.parentFile?.mkdirs()
-            richTextFile.writeText(SharedPdfRichTextSerializer.encode(richDocument))
-            richTextFile.setLastModified(timestamp)
+            if (richDocument.text.isEmpty() && richDocument.spans.isEmpty()) {
+                if (richTextFile.isFile) {
+                    val deleted = richTextFile.delete()
+                    logDesktopCloudAnnotations { "desktop.import.delete_text_empty book=${book.id} deleted=$deleted" }
+                } else {
+                    logDesktopCloudAnnotations { "desktop.import.text_empty book=${book.id} existing=false" }
+                }
+            } else {
+                richTextFile.parentFile?.mkdirs()
+                richTextFile.writeText(SharedPdfRichTextSerializer.encode(richDocument))
+                richTextFile.setLastModified(timestamp)
+                logDesktopCloudAnnotations {
+                    "desktop.import.write_text book=${book.id} textChars=${richDocument.text.length} " +
+                        "spans=${richDocument.spans.size} bytes=${richTextFile.length()} ts=${richTextFile.lastModified()}"
+                }
+            }
         } ?: run {
-            if (richTextFile.isFile) richTextFile.delete()
+            if (richTextFile.isFile) {
+                val deleted = richTextFile.delete()
+                logDesktopCloudAnnotations { "desktop.import.delete_text_missing book=${book.id} deleted=$deleted" }
+            } else {
+                logDesktopCloudAnnotations { "desktop.import.no_text_payload book=${book.id} existing=false" }
+            }
+        }
+        logDesktopCloudAnnotations {
+            "desktop.import.done book=${book.id} remoteTs=$timestamp ${localAnnotationDebugSummary(book)}"
         }
         return true
     }
 }
 
+private fun localAnnotationPayloadTimestamp(path: String): Long {
+    return maxOf(
+        desktopPdfAnnotationFile(path).lastModifiedIfSyncableAnnotations(),
+        desktopPdfAnnotationDeletionFile(path).lastModifiedIfSyncableAnnotationDeletions(),
+        desktopPdfRichTextFile(path).lastModifiedIfSyncableRichText()
+    )
+}
+
 private val cloudSidecarJson = Json {
     ignoreUnknownKeys = true
     prettyPrint = true
@@ -136,3 +281,31 @@ private fun JsonObject.hasPdfAnnotationPayload(): Boolean {
 private fun File.lastModifiedIfFile(): Long {
     return if (isFile) lastModified() else 0L
 }
+
+private fun File.hasSyncablePdfAnnotations(): Boolean {
+    return isFile && desktopPdfAnnotationElementForSync(readText()) != null
+}
+
+private fun File.lastModifiedIfSyncableAnnotations(): Long {
+    return if (hasSyncablePdfAnnotations()) lastModified() else 0L
+}
+
+private fun File.annotationDeletionCount(): Int {
+    return if (isFile) SharedPdfAnnotationSidecarCodec.annotationDeletionsFromJson(readText()).size else 0
+}
+
+private fun File.hasSyncablePdfAnnotationDeletions(): Boolean {
+    return annotationDeletionCount() > 0
+}
+
+private fun File.lastModifiedIfSyncableAnnotationDeletions(): Long {
+    return if (hasSyncablePdfAnnotationDeletions()) lastModified() else 0L
+}
+
+private fun File.hasSyncablePdfRichText(): Boolean {
+    return isFile && desktopPdfRichTextElementForSync(readText()) != null
+}
+
+private fun File.lastModifiedIfSyncableRichText(): Long {
+    return if (hasSyncablePdfRichText()) lastModified() else 0L
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopCloudSync.kt

@@ -7,9 +7,17 @@ import com.aryan.reader.shared.EpubAnnotationSerializer
 import com.aryan.reader.shared.EpubBookmark
 import com.aryan.reader.shared.FileType
 import com.aryan.reader.shared.ReaderLocator
+import com.aryan.reader.shared.SharedCloudBookMetadataWinner
 import com.aryan.reader.shared.SharedFileCapabilities
 import com.aryan.reader.shared.SharedReaderScreenState
 import com.aryan.reader.shared.ShelfRecord
+import com.aryan.reader.shared.sharedCloudBookMetadataWinner
+import com.aryan.reader.shared.shouldDownloadRemoteCloudBookContent
+import com.aryan.reader.shared.shouldUploadLocalCloudBookContent
+import com.aryan.reader.shared.sharedCloudBookContentFileName
+import com.aryan.reader.shared.toStablePositionCfi
+import com.aryan.reader.shared.pdf.SharedPdfAnnotationSidecarCodec
+import com.aryan.reader.shared.pdf.SharedPdfReaderViewport
 import com.aryan.reader.shared.reader.ReaderBookmark
 import java.io.File
 
@@ -31,7 +39,8 @@ internal data class DesktopCloudSyncResult(
     val shelfRefs: List<BookShelfRef>,
     val customFonts: List<CustomFontItem>,
     val uploadedBooks: Int = 0,
-    val downloadedBooks: Int = 0
+    val downloadedBooks: Int = 0,
+    val pendingContentDownloads: Int = 0
 )
 
 internal class DesktopCloudSync(
@@ -47,13 +56,22 @@ internal class DesktopCloudSync(
         var customFonts = input.customFonts
         var uploadedBooks = 0
         var downloadedBooks = 0
+        var pendingContentDownloads = 0
 
+        logDesktopCloudSync {
+            "desktop.engine.full_sync.start user=${input.userId} device=${input.deviceId} " +
+                "localBooks=${input.state.rawLibraryBooks.size} includeFolderBooks=${input.includeFolderBooks}"
+        }
         val remoteBooks = firestoreRepository.getAllBooks(input.userId, input.idToken)
             .filterNot { isDesktopPdfReflowBookId(it.bookId) }
             .filterNot { SharedFileCapabilities.isManualOnlyReaderFileName(it.displayName) }
         val remoteShelves = firestoreRepository.getAllShelves(input.userId, input.idToken)
         val remoteFonts = firestoreRepository.getAllFonts(input.userId, input.idToken)
         var driveFiles = driveRepository.getFiles(input.driveAccessToken).associateBy { it.name }
+        logDesktopCloudSync {
+            "desktop.engine.full_sync.loaded user=${input.userId} remoteBooks=${remoteBooks.size} " +
+                "remoteShelves=${remoteShelves.size} remoteFonts=${remoteFonts.size} driveFiles=${driveFiles.size}"
+        }
 
         val localBooks = state.rawLibraryBooks
             .filterNot { isDesktopPdfReflowBookId(it.id) }
@@ -71,6 +89,7 @@ internal class DesktopCloudSync(
 
             when {
                 local != null && remote == null -> {
+                    logDesktopCloudSync { "desktop.engine.book_decision action=upload_new ${local.desktopCloudSyncSummary()}" }
                     uploadBookAndMetadata(input, local, uploadContent = true)?.let { synced ->
                         state = state.upsertCloudBook(synced)
                         uploadedBooks += 1
@@ -78,22 +97,33 @@ internal class DesktopCloudSync(
                 }
 
                 local == null && remote != null -> {
-                    if (remote.isDeleted) return@forEach
+                    if (remote.isDeleted) {
+                        logDesktopCloudSync { "desktop.engine.book_decision action=skip_deleted_remote_only ${remote.desktopCloudSyncSummary()}" }
+                        return@forEach
+                    }
+                    logDesktopCloudSync { "desktop.engine.book_decision action=apply_remote_new ${remote.desktopCloudSyncSummary()}" }
                     val downloaded = downloadRemoteBook(input.driveAccessToken, remote, null, driveFiles)
-                    val remoteBook = downloaded ?: remote.toDesktopBookItem()
+                    if (downloaded == null) {
+                        pendingContentDownloads += 1
+                        logDesktopCloudSync {
+                            "desktop.engine.book_decision action=defer_remote_new_pending_content " +
+                                remote.desktopCloudSyncSummary()
+                        }
+                        return@forEach
+                    }
+                    val remoteBook = downloaded
                     state = state.upsertCloudBook(remoteBook)
-                    if (downloaded != null) downloadedBooks += 1
+                    downloadedBooks += 1
+                    importDesktopPdfBookmarksMetadata(remoteBook, remote.bookmarksJson, remote.lastModifiedTimestamp)
                     if (remote.hasAnnotations) {
-                        downloadAnnotations(input.driveAccessToken, remoteBook, remote.lastModifiedTimestamp)
+                        val remoteAnnotationTimestamp = remote.effectiveCloudAnnotationModifiedTimestamp(
+                            remoteAnnotationDriveFileTimestamp(remote.bookId, driveFiles)
+                        )
+                        downloadAnnotations(input.driveAccessToken, remoteBook, remoteAnnotationTimestamp)
                     }
                 }
 
                 local != null && remote != null -> {
-                    if (remote.isDeleted) {
-                        state = state.removeCloudBook(bookId)
-                        return@forEach
-                    }
-
                     val remoteBook = remote.toDesktopBookItem(existing = local)
                     val shouldDownloadContent = shouldDownloadRemoteBookContent(local, remote)
                     val downloaded = if (shouldDownloadContent) {
@@ -101,24 +131,165 @@ internal class DesktopCloudSync(
                     } else {
                         null
                     }
-                    val localSidecarTimestampBeforeMerge = DesktopCloudSidecarSync.localAnnotationTimestamp(local)
-                    val localMetadataTimestamp = maxOf(local.timestamp, localSidecarTimestampBeforeMerge)
-
-                    if (localMetadataTimestamp > remote.lastModifiedTimestamp) {
-                        uploadBookAndMetadata(input, local, uploadContent = shouldUploadLocalBookContent(local, remote))?.let { synced ->
-                            state = state.upsertCloudBook(synced)
-                            uploadedBooks += 1
+                    if (shouldDownloadContent && downloaded == null) {
+                        pendingContentDownloads += 1
+                    }
+                    val localContentAvailable = local.path?.let(::File)?.isFile == true
+                    if (shouldDownloadContent && downloaded == null && !localContentAvailable) {
+                        logDesktopCloudSync {
+                            "desktop.engine.book_decision action=defer_existing_pending_content book=$bookId " +
+                                local.desktopCloudSyncSummary() + " " + remote.desktopCloudSyncSummary()
                         }
-                    } else if (remote.lastModifiedTimestamp > local.timestamp || downloaded != null) {
-                        state = state.upsertCloudBook(downloaded ?: remoteBook)
+                        state = state.removeCloudBook(bookId)
+                        return@forEach
+                    }
+                    val localSidecarTimestampBeforeMerge = DesktopCloudSidecarSync.localAnnotationTimestamp(local)
+                    val metadataWinner = sharedCloudBookMetadataWinner(
+                        localModifiedTimestamp = local.timestamp,
+                        remoteModifiedTimestamp = remote.lastModifiedTimestamp
+                    )
+                    val localMetadataWins = metadataWinner == SharedCloudBookMetadataWinner.LOCAL
+                    val localReadingTimestamp = local.effectiveCloudReadingPositionModifiedTimestamp()
+                    val remoteReadingTimestamp = remote.effectiveCloudReadingPositionModifiedTimestamp()
+                    val remoteAnnotationDriveTimestamp = remoteAnnotationDriveFileTimestamp(bookId, driveFiles)
+                    val remoteAnnotationTimestamp = remote.effectiveCloudAnnotationModifiedTimestamp(remoteAnnotationDriveTimestamp)
+                    val localReadingPositionShouldUpload = localReadingTimestamp > remoteReadingTimestamp
+                    val localAnnotationsShouldUpload = shouldUploadLocalAnnotations(
+                        local = local,
+                        remote = remote,
+                        remoteAnnotationModifiedTimestamp = remoteAnnotationTimestamp,
+                        localSidecarTimestamp = localSidecarTimestampBeforeMerge
+                    )
+                    logDesktopCloudAnnotations {
+                        "desktop.sync.inspect book=$bookId remoteHas=${remote.hasAnnotations} " +
+                            "remoteTs=${remote.lastModifiedTimestamp} remoteAnnTs=$remoteAnnotationTimestamp " +
+                            "remoteDriveAnnTs=$remoteAnnotationDriveTimestamp localTs=${local.timestamp} " +
+                            "remoteReadTs=$remoteReadingTimestamp localReadTs=$localReadingTimestamp " +
+                            "localShouldUpload=$localAnnotationsShouldUpload " +
+                            DesktopCloudSidecarSync.localAnnotationDebugSummary(local)
+                    }
+                    logDesktopCloudSync {
+                        "desktop.engine.book_compare book=$bookId winner=$metadataWinner shouldDownloadContent=$shouldDownloadContent " +
+                            "downloadedContent=${downloaded != null} sidecarTs=$localSidecarTimestampBeforeMerge " +
+                            "uploadAnnotations=$localAnnotationsShouldUpload uploadReading=$localReadingPositionShouldUpload " +
+                            local.desktopCloudSyncSummary() + " " + remote.desktopCloudSyncSummary()
                     }
 
-                    val localSidecarTimestamp = DesktopCloudSidecarSync.localAnnotationTimestamp(downloaded ?: local)
-                    val needsAnnotationDownload = remote.hasAnnotations &&
-                        (remote.lastModifiedTimestamp > localSidecarTimestamp || localSidecarTimestamp == 0L)
+                    if (remote.isDeleted) {
+                        if (localMetadataWins) {
+                            logDesktopCloudSync { "desktop.engine.book_decision action=resurrect_upload_local book=$bookId" }
+                            uploadBookAndMetadata(
+                                input = input,
+                                book = local,
+                                uploadContent = shouldUploadLocalBookContent(local, null),
+                                uploadAnnotations = DesktopCloudSidecarSync.hasLocalAnnotationData(local)
+                            )?.let { synced ->
+                                state = state.upsertCloudBook(synced)
+                                uploadedBooks += 1
+                            }
+                        } else if (metadataWinner == SharedCloudBookMetadataWinner.REMOTE) {
+                            logDesktopCloudSync { "desktop.engine.book_decision action=apply_remote_delete book=$bookId" }
+                            state = state.removeCloudBook(bookId)
+                        } else {
+                            logDesktopCloudSync { "desktop.engine.book_decision action=skip_equal_delete book=$bookId" }
+                        }
+                        return@forEach
+                    }
+
+                    if (localMetadataWins) {
+                        logDesktopCloudSync {
+                            "desktop.engine.book_decision action=upload_local book=$bookId " +
+                                "uploadContent=${shouldUploadLocalBookContent(local, remote)} " +
+                                "uploadAnnotations=$localAnnotationsShouldUpload " +
+                                "preserveRemoteReading=${remoteReadingTimestamp > localReadingTimestamp}"
+                        }
+                        val localForMetadata = if (remoteReadingTimestamp > localReadingTimestamp) {
+                            local.withCloudReadingPosition(remote)
+                        } else {
+                            local
+                        }
+                        val bookForMetadata = localForMetadata.withDownloadedCloudContent(downloaded, replacePath = false)
+                        uploadBookAndMetadata(
+                            input = input,
+                            book = bookForMetadata,
+                            uploadContent = shouldUploadLocalBookContent(local, remote),
+                            uploadAnnotations = localAnnotationsShouldUpload,
+                            remoteHasAnnotations = remote.hasAnnotations,
+                            remoteAnnotationModifiedTimestamp = remoteAnnotationTimestamp,
+                            remoteContentModifiedTimestamp = remote.fileContentModifiedTimestamp
+                        )?.let { synced ->
+                            state = state.upsertCloudBook(synced.withDownloadedCloudContent(downloaded))
+                            uploadedBooks += 1
+                        }
+                    } else if (metadataWinner == SharedCloudBookMetadataWinner.REMOTE || downloaded != null) {
+                        logDesktopCloudSync {
+                            "desktop.engine.book_decision action=apply_remote book=$bookId " +
+                                "metadataWinner=$metadataWinner downloadedContent=${downloaded != null}"
+                        }
+                        val mergedBook = downloaded ?: remoteBook
+                        state = state.upsertCloudBook(mergedBook)
+                        importDesktopPdfBookmarksMetadata(mergedBook, remote.bookmarksJson, remote.lastModifiedTimestamp)
+                    }
+
+                    if (!localMetadataWins && (localAnnotationsShouldUpload || localReadingPositionShouldUpload)) {
+                        val metadataBook = state.rawLibraryBooks.firstOrNull { it.id == bookId }
+                            ?: remoteBook
+                        logDesktopCloudAnnotations {
+                            "desktop.sync.upload_local_supplement book=$bookId winner=$metadataWinner " +
+                                "remoteHas=${remote.hasAnnotations} remoteTs=${remote.lastModifiedTimestamp} " +
+                                "remoteAnnTs=$remoteAnnotationTimestamp " +
+                                "localSidecarTs=$localSidecarTimestampBeforeMerge " +
+                                "uploadAnnotations=$localAnnotationsShouldUpload uploadReading=$localReadingPositionShouldUpload " +
+                                "localReadTs=$localReadingTimestamp remoteReadTs=$remoteReadingTimestamp"
+                        }
+                        logDesktopCloudSync {
+                            "desktop.engine.book_decision action=upload_local_supplement book=$bookId " +
+                                "metadataWinner=$metadataWinner sidecarTs=$localSidecarTimestampBeforeMerge " +
+                                "uploadAnnotations=$localAnnotationsShouldUpload uploadReading=$localReadingPositionShouldUpload " +
+                                metadataBook.desktopCloudSyncSummary()
+                        }
+                        uploadBookAndMetadata(
+                            input = input,
+                            book = metadataBook,
+                            uploadContent = false,
+                            uploadAnnotations = localAnnotationsShouldUpload,
+                            remoteHasAnnotations = remote.hasAnnotations,
+                            remoteAnnotationModifiedTimestamp = remoteAnnotationTimestamp,
+                            remoteContentModifiedTimestamp = remote.fileContentModifiedTimestamp
+                        )?.let { synced ->
+                            state = state.upsertCloudBook(synced.withDownloadedCloudContent(downloaded))
+                            uploadedBooks += 1
+                        }
+                    }
+
+                    val localSidecarTimestamp = DesktopCloudSidecarSync.localAnnotationPayloadTimestamp(downloaded ?: local)
+                    val needsAnnotationDownload = !localMetadataWins &&
+                        !localAnnotationsShouldUpload &&
+                        remote.hasAnnotations &&
+                        (remoteAnnotationTimestamp > localSidecarTimestamp || localSidecarTimestamp == 0L)
                     if (needsAnnotationDownload) {
+                        logDesktopCloudAnnotations {
+                            "desktop.sync.download_remote_annotations book=$bookId remoteTs=${remote.lastModifiedTimestamp} " +
+                                "remoteAnnTs=$remoteAnnotationTimestamp " +
+                                "localSidecarTs=$localSidecarTimestamp localMetadataWins=$localMetadataWins " +
+                                "localShouldUpload=$localAnnotationsShouldUpload"
+                        }
+                        logDesktopCloudSync {
+                            "desktop.engine.sidecar_download_start book=$bookId remoteTs=${remote.lastModifiedTimestamp} " +
+                                "remoteAnnTs=$remoteAnnotationTimestamp localSidecarTs=$localSidecarTimestamp localMetadataWins=$localMetadataWins"
+                        }
                         val targetBook = downloaded ?: state.rawLibraryBooks.firstOrNull { it.id == bookId } ?: local
-                        downloadAnnotations(input.driveAccessToken, targetBook, remote.lastModifiedTimestamp)
+                        downloadAnnotations(input.driveAccessToken, targetBook, remoteAnnotationTimestamp)
+                    } else {
+                        logDesktopCloudAnnotations {
+                            "desktop.sync.skip_remote_annotations book=$bookId remoteHas=${remote.hasAnnotations} " +
+                                "remoteAnnTs=$remoteAnnotationTimestamp localSidecarTs=$localSidecarTimestamp localMetadataWins=$localMetadataWins " +
+                                "localShouldUpload=$localAnnotationsShouldUpload"
+                        }
+                        logDesktopCloudSync {
+                            "desktop.engine.sidecar_download_skip book=$bookId remoteHasAnnotations=${remote.hasAnnotations} " +
+                                "localSidecarTs=$localSidecarTimestamp localMetadataWins=$localMetadataWins"
+                        }
                     }
                 }
             }
@@ -135,18 +306,49 @@ internal class DesktopCloudSync(
                 val localFile = book.path?.let(::File)
                 when {
                     localFile?.isFile == true && driveFiles[driveName] == null -> {
-                        if (driveRepository.uploadFile(input.driveAccessToken, book.id, localFile, book.type) != null) {
-                            uploadedBooks += 1
+                        val remote = remoteBooksMap[book.id]
+                        if (remote == null || shouldUploadLocalBookContent(book, remote)) {
+                            logDesktopCloudSync { "desktop.engine.content_upload_missing_remote book=${book.id} driveName=$driveName" }
+                            uploadBookAndMetadata(
+                                input = input,
+                                book = book,
+                                uploadContent = true,
+                                uploadAnnotations = false,
+                                remoteHasAnnotations = remote?.hasAnnotations == true,
+                                remoteAnnotationModifiedTimestamp = remote?.effectiveCloudAnnotationModifiedTimestamp(
+                                    remoteAnnotationDriveFileTimestamp(book.id, driveFiles)
+                                ) ?: 0L,
+                                remoteContentModifiedTimestamp = remote?.fileContentModifiedTimestamp
+                            )?.let { synced ->
+                                state = state.upsertCloudBook(synced)
+                                uploadedBooks += 1
+                            }
+                        } else {
+                            pendingContentDownloads += 1
+                            logDesktopCloudSync {
+                                "desktop.engine.content_wait_missing_remote book=${book.id} driveName=$driveName " +
+                                    "localContentTs=${book.fileContentModifiedTimestamp} remoteContentTs=${remote.fileContentModifiedTimestamp}"
+                            }
                         }
                     }
 
                     (localFile == null || !localFile.isFile) && driveFiles[driveName] != null -> {
                         val remote = remoteBooksMap[book.id] ?: return@forEach
-                        downloadRemoteBook(input.driveAccessToken, remote, book, driveFiles)?.let { downloaded ->
+                        logDesktopCloudSync { "desktop.engine.content_download_missing_local book=${book.id} driveName=$driveName" }
+                        val downloaded = downloadRemoteBook(input.driveAccessToken, remote, book, driveFiles)
+                        if (downloaded != null) {
                             state = state.upsertCloudBook(downloaded)
                             downloadedBooks += 1
+                        } else {
+                            pendingContentDownloads += 1
                         }
                     }
+
+                    (localFile == null || !localFile.isFile) && driveFiles[driveName] == null -> {
+                        pendingContentDownloads += 1
+                        logDesktopCloudSync { "desktop.engine.content_wait_missing_remote book=${book.id} driveName=$driveName" }
+                        state = state.removeCloudBook(book.id)
+                    }
                 }
             }
 
@@ -172,55 +374,205 @@ internal class DesktopCloudSync(
             remoteFonts = remoteFonts
         )
 
+        logDesktopCloudSync {
+            "desktop.engine.full_sync.complete user=${input.userId} uploaded=$uploadedBooks downloaded=$downloadedBooks " +
+                "pendingContent=$pendingContentDownloads books=${state.rawLibraryBooks.size}"
+        }
         return DesktopCloudSyncResult(
             state = state,
             shelfRecords = shelfRecords,
             shelfRefs = shelfRefs,
             customFonts = customFonts.filterNot { it.isDeleted }.sortedBy { it.displayName.lowercase() },
             uploadedBooks = uploadedBooks,
-            downloadedBooks = downloadedBooks
+            downloadedBooks = downloadedBooks,
+            pendingContentDownloads = pendingContentDownloads
         )
     }
 
     suspend fun uploadBookAndMetadata(
         input: DesktopCloudSyncInput,
         book: BookItem,
-        uploadContent: Boolean
+        uploadContent: Boolean,
+        uploadAnnotations: Boolean = true,
+        remoteHasAnnotations: Boolean = false,
+        remoteAnnotationModifiedTimestamp: Long = 0L,
+        remoteContentModifiedTimestamp: Long? = null
     ): BookItem? {
-        if (isDesktopPdfReflowBookId(book.id)) return null
-        if (book.sourceFolder != null) return null
-        if (book.path?.startsWith("opds-pse") == true) return null
-        if (SharedFileCapabilities.isManualOnlyReaderFileName(book.displayName)) return null
+        if (isDesktopPdfReflowBookId(book.id)) {
+            logDesktopCloudSync { "desktop.upload.skip reason=reflow ${book.desktopCloudSyncSummary()}" }
+            return null
+        }
+        if (book.sourceFolder != null) {
+            logDesktopCloudSync { "desktop.upload.skip reason=folder_book ${book.desktopCloudSyncSummary()}" }
+            return null
+        }
+        if (book.path?.startsWith("opds-pse") == true) {
+            logDesktopCloudSync { "desktop.upload.skip reason=opds_stream ${book.desktopCloudSyncSummary()}" }
+            return null
+        }
+        if (SharedFileCapabilities.isManualOnlyReaderFileName(book.displayName)) {
+            logDesktopCloudSync { "desktop.upload.skip reason=manual_only ${book.desktopCloudSyncSummary()}" }
+            return null
+        }
+        logDesktopCloudSync {
+            "desktop.upload.start uploadContent=$uploadContent uploadAnnotations=$uploadAnnotations " +
+                "remoteHasAnnotations=$remoteHasAnnotations ${book.desktopCloudSyncSummary()}"
+        }
         if (uploadContent) {
             val source = book.path?.let(::File)?.takeIf { it.isFile }
             if (source != null && driveRepository.uploadFile(input.driveAccessToken, book.id, source, book.type) == null) {
+                logDesktopCloudSync { "desktop.upload.content_failed book=${book.id} path=${source.absolutePath}" }
                 return null
             }
+            logDesktopCloudSync { "desktop.upload.content_success book=${book.id} path=${source?.absolutePath ?: "none"}" }
         }
 
-        val bundle = DesktopCloudSidecarSync.exportAnnotationBundle(book)
+        val hasLocalAnnotations = DesktopCloudSidecarSync.hasLocalAnnotationData(book)
+        val shouldUploadAnnotations = uploadAnnotations || (!remoteHasAnnotations && hasLocalAnnotations)
+        val bundle = if (shouldUploadAnnotations) DesktopCloudSidecarSync.exportAnnotationBundle(book) else null
+        var uploadedAnnotationTimestamp = 0L
+        logDesktopCloudAnnotations {
+            "desktop.upload.annotation_decision book=${book.id} uploadAnnotations=$uploadAnnotations " +
+                "remoteHas=$remoteHasAnnotations hasLocal=$hasLocalAnnotations shouldUpload=$shouldUploadAnnotations " +
+                "bundleBytes=${bundle?.length() ?: 0L} " + DesktopCloudSidecarSync.localAnnotationDebugSummary(book)
+        }
         try {
-            if (bundle != null && driveRepository.uploadAnnotationFile(input.driveAccessToken, book.id, bundle) == null) {
-                return null
+            if (bundle != null) {
+                val mergedRemoteIntoUpload = mergeRemoteAnnotationsIntoUploadBundle(
+                    accessToken = input.driveAccessToken,
+                    book = book,
+                    bundle = bundle,
+                    remoteHasAnnotations = remoteHasAnnotations
+                )
+                val uploadedAnnotationFile = driveRepository.uploadAnnotationFile(input.driveAccessToken, book.id, bundle)
+                if (uploadedAnnotationFile == null) {
+                    logDesktopCloudAnnotations { "desktop.upload.sidecar_failed book=${book.id} bytes=${bundle.length()}" }
+                    logDesktopCloudSync { "desktop.upload.sidecar_failed book=${book.id} bytes=${bundle.length()}" }
+                    return null
+                }
+                uploadedAnnotationTimestamp = uploadedAnnotationFile.modifiedTimeMillis
+                if (mergedRemoteIntoUpload) {
+                    val appliedMergedLocal = DesktopCloudSidecarSync.importAnnotationBundle(
+                        book = book,
+                        rawJson = bundle.readText(),
+                        timestamp = uploadedAnnotationTimestamp
+                    )
+                    logDesktopCloudAnnotations {
+                        "desktop.upload.local_apply_merged book=${book.id} applied=$appliedMergedLocal " +
+                            "driveTs=$uploadedAnnotationTimestamp bytes=${bundle.length()}"
+                    }
+                }
+                DesktopCloudSidecarSync.markAnnotationPayloadSynced(book, uploadedAnnotationTimestamp)
+            }
+            if (bundle != null) {
+                logDesktopCloudAnnotations {
+                    "desktop.upload.sidecar_success book=${book.id} bytes=${bundle.length()} driveTs=$uploadedAnnotationTimestamp"
+                }
+            } else {
+                logDesktopCloudAnnotations {
+                    "desktop.upload.sidecar_skipped book=${book.id} shouldUpload=$shouldUploadAnnotations hasLocal=$hasLocalAnnotations"
+                }
+            }
+            logDesktopCloudSync {
+                "desktop.upload.sidecar_decision book=${book.id} hasLocal=$hasLocalAnnotations " +
+                    "shouldUpload=$shouldUploadAnnotations uploaded=${bundle != null} bytes=${bundle?.length() ?: 0L}"
             }
         } finally {
             bundle?.delete()
         }
 
         val now = System.currentTimeMillis()
-        val syncedBook = book.copy(timestamp = now)
+        val syncedBook = book.copy(
+            timestamp = now,
+            readingPositionModifiedTimestamp = book.effectiveCloudReadingPositionModifiedTimestamp()
+        )
+        val localAnnotationTimestamp = DesktopCloudSidecarSync.localAnnotationPayloadTimestamp(book)
+        val syncedAnnotationTimestamp = if (bundle != null) {
+            uploadedAnnotationTimestamp.takeIf { it > 0L } ?: maxOf(localAnnotationTimestamp, now)
+        } else if (remoteHasAnnotations) {
+            remoteAnnotationModifiedTimestamp
+        } else {
+            0L
+        }
+        val syncedHasAnnotations = if (uploadAnnotations) {
+            syncedAnnotationTimestamp > 0L || (bundle != null && hasLocalAnnotations)
+        } else {
+            remoteHasAnnotations || syncedAnnotationTimestamp > 0L || bundle != null || hasLocalAnnotations
+        }
         firestoreRepository.syncBookMetadata(
             userId = input.userId,
             book = syncedBook.toDesktopCloudBookMetadata(
-                hasAnnotations = bundle != null,
-                timestamp = now
+                hasAnnotations = syncedHasAnnotations,
+                timestamp = now,
+                annotationModifiedTimestamp = syncedAnnotationTimestamp,
+                contentTimestampOverride = if (uploadContent) null else remoteContentModifiedTimestamp
             ),
             originDeviceId = input.deviceId,
             idToken = input.idToken
         )
+        logDesktopCloudSync {
+            "desktop.upload.metadata_success user=${input.userId} device=${input.deviceId} " +
+                "oldTs=${book.timestamp} newTs=$now hasAnnotations=$syncedHasAnnotations " +
+                syncedBook.desktopCloudSyncSummary("synced")
+        }
+        logDesktopCloudAnnotations {
+            "desktop.upload.metadata_success book=${book.id} oldTs=${book.timestamp} newTs=$now " +
+                "readTs=${syncedBook.effectiveCloudReadingPositionModifiedTimestamp()} " +
+                "annTs=$syncedAnnotationTimestamp hasAnnotations=$syncedHasAnnotations"
+        }
         return syncedBook
     }
 
+    private suspend fun mergeRemoteAnnotationsIntoUploadBundle(
+        accessToken: String,
+        book: BookItem,
+        bundle: File,
+        remoteHasAnnotations: Boolean
+    ): Boolean {
+        if (!remoteHasAnnotations || !bundle.isFile) return false
+        val remoteTemp = File(desktopUserCacheRoot(), "remote_annotation_${book.id.toDesktopSafeFileName()}_${System.nanoTime()}.json")
+        try {
+            val didDownload = driveRepository.downloadAnnotationFile(accessToken, book.id, remoteTemp)
+            if (!didDownload || !remoteTemp.isFile) {
+                logDesktopCloudAnnotations {
+                    "desktop.upload.merge_remote_missing book=${book.id} didDownload=$didDownload " +
+                        "tempExists=${remoteTemp.exists()} localBytes=${bundle.length()}"
+                }
+                return false
+            }
+            val localRaw = bundle.readText()
+            val remoteRaw = remoteTemp.readText()
+            val mergedRaw = SharedPdfAnnotationSidecarCodec.mergeAnnotationDataJson(
+                localDataJson = localRaw,
+                remoteDataJson = remoteRaw,
+                preferRemoteOnConflict = false
+            )
+            val localCount = SharedPdfAnnotationSidecarCodec.annotationCountFromDataJson(localRaw)
+            val remoteCount = SharedPdfAnnotationSidecarCodec.annotationCountFromDataJson(remoteRaw)
+            val mergedCount = SharedPdfAnnotationSidecarCodec.annotationCountFromDataJson(mergedRaw)
+            if (mergedRaw != localRaw) {
+                bundle.writeText(mergedRaw)
+                logDesktopCloudAnnotations {
+                    "desktop.upload.merge_remote_applied book=${book.id} localCount=$localCount " +
+                        "remoteCount=$remoteCount mergedCount=$mergedCount mergedBytes=${bundle.length()}"
+                }
+                return true
+            } else {
+                logDesktopCloudAnnotations {
+                    "desktop.upload.merge_remote_noop book=${book.id} localCount=$localCount " +
+                        "remoteCount=$remoteCount mergedCount=$mergedCount"
+                }
+            }
+        } catch (error: Exception) {
+            logDesktopCloudAnnotations {
+                "desktop.upload.merge_remote_failed book=${book.id} error=${error.message.orEmpty().logPreview(240)}"
+            }
+        } finally {
+            remoteTemp.delete()
+        }
+        return false
+    }
+
     suspend fun deleteBooksFromCloud(
         userId: String,
         idToken: String,
@@ -247,7 +599,7 @@ internal class DesktopCloudSync(
                 desktopCloudBookDriveFileName(book.id, book.type)
                     ?.let { driveFiles[it]?.id }
                     ?.let { driveRepository.deleteDriveFile(accessToken, it) }
-                driveFiles["annotation_${book.id}.json"]?.id
+                driveFiles[desktopCloudAnnotationDriveFileName(book.id)]?.id
                     ?.let { driveRepository.deleteDriveFile(accessToken, it) }
             }
     }
@@ -293,8 +645,32 @@ internal class DesktopCloudSync(
     private suspend fun downloadAnnotations(accessToken: String, book: BookItem, timestamp: Long): Boolean {
         val temp = File(desktopUserCacheRoot(), "temp_download_${book.id.toDesktopSafeFileName()}_${System.nanoTime()}.json")
         return try {
-            if (!driveRepository.downloadAnnotationFile(accessToken, book.id, temp) || !temp.isFile) return false
-            DesktopCloudSidecarSync.importAnnotationBundle(book, temp.readText(), timestamp)
+            logDesktopCloudAnnotations {
+                "desktop.download.start book=${book.id} remoteTs=$timestamp temp=${temp.name} " +
+                    DesktopCloudSidecarSync.localAnnotationDebugSummary(book)
+            }
+            logDesktopCloudSync { "desktop.sidecar_download.start book=${book.id} remoteTs=$timestamp temp=${temp.name}" }
+            if (!driveRepository.downloadAnnotationFile(accessToken, book.id, temp) || !temp.isFile) {
+                logDesktopCloudAnnotations {
+                    "desktop.download.missing book=${book.id} remoteTs=$timestamp tempExists=${temp.exists()} tempBytes=${temp.length()}"
+                }
+                logDesktopCloudSync { "desktop.sidecar_download.missing book=${book.id} remoteTs=$timestamp" }
+                return false
+            }
+            val raw = temp.readText()
+            logDesktopCloudAnnotations {
+                "desktop.download.success book=${book.id} remoteTs=$timestamp bytes=${raw.length}"
+            }
+            val appliedTimestamp = timestamp.takeIf { it > 0L } ?: temp.lastModified().takeIf { it > 0L } ?: 0L
+            val applied = DesktopCloudSidecarSync.importAnnotationBundle(book, raw, appliedTimestamp)
+            logDesktopCloudAnnotations {
+                "desktop.download.applied book=${book.id} remoteTs=$timestamp appliedTs=$appliedTimestamp applied=$applied " +
+                    DesktopCloudSidecarSync.localAnnotationDebugSummary(book)
+            }
+            logDesktopCloudSync {
+                "desktop.sidecar_download.applied book=${book.id} remoteTs=$timestamp appliedTs=$appliedTimestamp bytes=${temp.length()} applied=$applied"
+            }
+            applied
         } finally {
             temp.delete()
         }
@@ -311,16 +687,23 @@ internal class DesktopCloudSync(
         val driveFile = driveFiles[driveName] ?: return null
         val extension = SharedFileCapabilities.primaryExtensionFor(type) ?: return null
         val destination = bookImporter.createBookFile("${remote.bookId.toDesktopSafeFileName()}.$extension")
+        logDesktopCloudSync { "desktop.content_download.start book=${remote.bookId} driveName=$driveName remoteContentTs=${remote.fileContentModifiedTimestamp}" }
         if (!driveRepository.downloadFile(accessToken, driveFile.id, destination)) {
             destination.delete()
+            logDesktopCloudSync { "desktop.content_download.failed book=${remote.bookId} driveName=$driveName" }
             return null
         }
         val contentTimestamp = remote.fileContentModifiedTimestamp.takeIf { it > 0L } ?: destination.lastModified()
         if (contentTimestamp > 0L) destination.setLastModified(contentTimestamp)
-        return remote.toDesktopBookItem(existing = existing, downloadedPath = destination.absolutePath).copy(
+        val downloaded = remote.toDesktopBookItem(existing = existing, downloadedPath = destination.absolutePath).copy(
             fileSize = destination.length(),
             fileContentModifiedTimestamp = contentTimestamp
         )
+        logDesktopCloudSync {
+            "desktop.content_download.success book=${remote.bookId} bytes=${destination.length()} contentTs=$contentTimestamp " +
+                downloaded.desktopCloudSyncSummary("downloaded")
+        }
+        return downloaded
     }
 
     private suspend fun syncFonts(
@@ -447,18 +830,28 @@ internal class DesktopCloudSync(
 
 internal fun BookItem.toDesktopCloudBookMetadata(
     hasAnnotations: Boolean,
-    timestamp: Long = this.timestamp
+    timestamp: Long = this.timestamp,
+    annotationModifiedTimestamp: Long = 0L,
+    contentTimestampOverride: Long? = null
 ): DesktopCloudBookMetadata {
-    val position = readerPosition
-    val bookmarksJson = readerBookmarks
-        .mapNotNull { it.toDesktopCloudEpubBookmarkOrNull() }
-        .takeIf { it.isNotEmpty() }
-        ?.let(EpubAnnotationSerializer::bookmarksToJson)
-    val highlightsJson = readerHighlights
-        .takeIf { it.isNotEmpty() }
-        ?.let(EpubAnnotationSerializer::highlightsToJson)
+    val position = readerPosition.takeIf { type.usesCloudLocatorMetadata() }
+    val supportsReaderAnnotations = type.usesCloudLocatorMetadata()
+    val bookmarksJson = desktopPdfBookmarksMetadataJson(this)
+        ?: if (supportsReaderAnnotations) {
+            readerBookmarks
+                .mapNotNull { it.toDesktopCloudEpubBookmarkOrNull() }
+                .let(EpubAnnotationSerializer::bookmarksToJson)
+        } else {
+            null
+        }
+    val highlightsJson = if (supportsReaderAnnotations) {
+        EpubAnnotationSerializer.highlightsToJson(readerHighlights)
+    } else {
+        null
+    }
     val localFile = path?.let(::File)
-    val contentTimestamp = fileContentModifiedTimestamp.takeIf { it > 0L }
+    val contentTimestamp = contentTimestampOverride
+        ?: fileContentModifiedTimestamp.takeIf { it > 0L }
         ?: localFile?.takeIf { it.isFile }?.lastModified()
         ?: 0L
     return DesktopCloudBookMetadata(
@@ -469,13 +862,15 @@ internal fun BookItem.toDesktopCloudBookMetadata(
         type = type.name,
         lastPositionCfi = position?.cloudPositionCfi(),
         lastChapterIndex = position?.chapterIndex,
-        locatorBlockIndex = null,
-        locatorCharOffset = null,
-        lastPage = position?.pageIndex ?: lastPageIndex,
+        locatorBlockIndex = position?.blockIndex,
+        locatorCharOffset = position?.charOffset,
+        lastPage = if (type.usesCloudLocatorMetadata()) position?.pageIndex ?: lastPageIndex else lastPageIndex,
         progressPercentage = progressPercentage,
         isRecent = isRecent,
         isDeleted = false,
         lastModifiedTimestamp = timestamp,
+        readingPositionModifiedTimestamp = effectiveCloudReadingPositionModifiedTimestamp(),
+        annotationModifiedTimestamp = annotationModifiedTimestamp,
         bookmarksJson = bookmarksJson,
         hasAnnotations = hasAnnotations,
         fileContentModifiedTimestamp = contentTimestamp,
@@ -498,11 +893,39 @@ internal fun DesktopCloudBookMetadata.toDesktopBookItem(
 ): BookItem {
     val type = fileType()
     val pageIndex = lastPage
-    val locator = ReaderLocator.fromLegacy(
-        chapterIndex = lastChapterIndex,
-        cfi = lastPositionCfi,
-        pageIndex = pageIndex
-    )
+    val locator = if (type.usesCloudLocatorMetadata()) {
+        ReaderLocator.fromLegacy(
+            chapterIndex = lastChapterIndex,
+            cfi = lastPositionCfi,
+            pageIndex = pageIndex
+        ).withFallbacks(
+            blockIndex = locatorBlockIndex,
+            charOffset = locatorCharOffset
+        )
+    } else {
+        null
+    }
+    val remoteReadingTimestamp = effectiveCloudReadingPositionModifiedTimestamp()
+    val localReadingTimestamp = existing?.effectiveCloudReadingPositionModifiedTimestamp() ?: 0L
+    val useRemoteReadingPosition = existing == null ||
+        remoteReadingTimestamp > localReadingTimestamp ||
+        (localReadingTimestamp == 0L && hasCloudReadingPosition())
+    val restoredPageIndex = if (useRemoteReadingPosition) pageIndex ?: existing?.lastPageIndex else existing?.lastPageIndex
+    val restoredReaderPosition = if (type.usesCloudLocatorMetadata()) {
+        if (useRemoteReadingPosition) {
+            locator?.takeIf {
+                it.chapterIndex != null ||
+                    it.pageIndex != null ||
+                    it.cfi != null ||
+                    it.startOffset != null ||
+                    it.blockIndex != null
+            } ?: existing?.readerPosition
+        } else {
+            existing?.readerPosition
+        }
+    } else {
+        null
+    }
     return BookItem(
         id = bookId,
         path = downloadedPath ?: existing?.path,
@@ -518,7 +941,7 @@ internal fun DesktopCloudBookMetadata.toDesktopBookItem(
         originalSeriesName = originalSeriesName ?: existing?.originalSeriesName,
         originalSeriesIndex = originalSeriesIndex ?: existing?.originalSeriesIndex,
         originalDescription = originalDescription ?: existing?.originalDescription,
-        progressPercentage = progressPercentage ?: existing?.progressPercentage,
+        progressPercentage = if (useRemoteReadingPosition) progressPercentage ?: existing?.progressPercentage else existing?.progressPercentage,
         isRecent = isRecent,
         fileSize = existing?.fileSize ?: 0L,
         fileContentModifiedTimestamp = fileContentModifiedTimestamp.takeIf { it > 0L }
@@ -529,12 +952,10 @@ internal fun DesktopCloudBookMetadata.toDesktopBookItem(
         seriesName = seriesName ?: existing?.seriesName,
         seriesIndex = seriesIndex ?: existing?.seriesIndex,
         tags = existing?.tags.orEmpty(),
-        lastPageIndex = pageIndex ?: existing?.lastPageIndex,
-        readerPosition = locator.takeIf {
-            it.chapterIndex != null || it.pageIndex != null || it.cfi != null || it.startOffset != null
-        } ?: existing?.readerPosition,
+        lastPageIndex = restoredPageIndex,
+        readerPosition = restoredReaderPosition,
         readerSettings = existing?.readerSettings,
-        readerBookmarks = if (bookmarksJson.isNullOrBlank()) {
+        readerBookmarks = if (type == FileType.PDF || bookmarksJson.isNullOrBlank()) {
             existing?.readerBookmarks.orEmpty()
         } else {
             EpubAnnotationSerializer.parseBookmarksJson(bookmarksJson).map { bookmark ->
@@ -552,10 +973,101 @@ internal fun DesktopCloudBookMetadata.toDesktopBookItem(
         } else {
             EpubAnnotationSerializer.parseHighlightsJson(highlightsJson)
         },
-        pdfReaderViewport = existing?.pdfReaderViewport
+        pdfReaderViewport = if (useRemoteReadingPosition) remotePdfViewport(existing, pageIndex) else existing?.pdfReaderViewport,
+        readingPositionModifiedTimestamp = if (useRemoteReadingPosition) remoteReadingTimestamp else localReadingTimestamp
     )
 }
 
+internal fun BookItem.withCloudReadingPosition(remote: DesktopCloudBookMetadata): BookItem {
+    val remoteType = remote.fileType()
+    val pageIndex = remote.lastPage
+    val locator = if (remoteType.usesCloudLocatorMetadata()) {
+        ReaderLocator.fromLegacy(
+            chapterIndex = remote.lastChapterIndex,
+            cfi = remote.lastPositionCfi,
+            pageIndex = pageIndex
+        ).withFallbacks(
+            blockIndex = remote.locatorBlockIndex,
+            charOffset = remote.locatorCharOffset
+        ).takeIf {
+            it.chapterIndex != null ||
+                it.pageIndex != null ||
+                it.cfi != null ||
+                it.startOffset != null ||
+                it.blockIndex != null
+        }
+    } else {
+        null
+    }
+    return copy(
+        lastPageIndex = pageIndex ?: lastPageIndex,
+        readerPosition = if (remoteType.usesCloudLocatorMetadata()) locator ?: readerPosition else null,
+        progressPercentage = remote.progressPercentage ?: progressPercentage,
+        pdfReaderViewport = if (remoteType.usesCloudLocatorMetadata()) {
+            pdfReaderViewport
+        } else {
+            remote.remotePdfViewport(this, pageIndex)
+        },
+        readingPositionModifiedTimestamp = remote.effectiveCloudReadingPositionModifiedTimestamp()
+    )
+}
+
+private fun DesktopCloudBookMetadata.remotePdfViewport(
+    existing: BookItem?,
+    pageIndex: Int?
+): SharedPdfReaderViewport? {
+    if (fileType().usesCloudLocatorMetadata() || pageIndex == null) return existing?.pdfReaderViewport
+    val base = existing?.pdfReaderViewport ?: SharedPdfReaderViewport()
+    return base.copy(
+        pageIndex = pageIndex,
+        horizontalScrollOffset = 0,
+        paginatedVerticalScrollOffset = 0,
+        verticalFirstPageIndex = pageIndex,
+        verticalFirstPageScrollOffset = 0
+    )
+}
+
+private fun FileType.usesCloudLocatorMetadata(): Boolean {
+    return this != FileType.PDF && this != FileType.PPTX && !SharedFileCapabilities.isComicArchive(this)
+}
+
+internal fun BookItem.hasCloudReadingPosition(): Boolean {
+    return lastPageIndex != null ||
+        readerPosition != null ||
+        (progressPercentage ?: 0f) > 0f
+}
+
+internal fun BookItem.effectiveCloudReadingPositionModifiedTimestamp(): Long {
+    return readingPositionModifiedTimestamp.takeIf { it > 0L }
+        ?: timestamp.takeIf { hasCloudReadingPosition() }
+        ?: 0L
+}
+
+internal fun DesktopCloudBookMetadata.hasCloudReadingPosition(): Boolean {
+    return lastChapterIndex != null ||
+        lastPage != null ||
+        !lastPositionCfi.isNullOrBlank() ||
+        locatorBlockIndex != null ||
+        locatorCharOffset != null ||
+        (progressPercentage ?: 0f) > 0f
+}
+
+internal fun DesktopCloudBookMetadata.effectiveCloudReadingPositionModifiedTimestamp(): Long {
+    return readingPositionModifiedTimestamp.takeIf { it > 0L }
+        ?: lastModifiedTimestamp.takeIf { hasCloudReadingPosition() }
+        ?: 0L
+}
+
+internal fun DesktopCloudBookMetadata.effectiveCloudAnnotationModifiedTimestamp(): Long {
+    return annotationModifiedTimestamp.takeIf { it > 0L }
+        ?: 0L
+}
+
+internal fun DesktopCloudBookMetadata.effectiveCloudAnnotationModifiedTimestamp(sidecarModifiedTimestamp: Long): Long {
+    return sidecarModifiedTimestamp.takeIf { it > 0L }
+        ?: effectiveCloudAnnotationModifiedTimestamp()
+}
+
 internal fun CustomFontItem.toDesktopCloudFontMetadata(): DesktopCloudFontMetadata {
     return DesktopCloudFontMetadata(
         id = id,
@@ -568,8 +1080,7 @@ internal fun CustomFontItem.toDesktopCloudFontMetadata(): DesktopCloudFontMetada
 }
 
 internal fun desktopCloudBookDriveFileName(bookId: String, type: FileType): String? {
-    val extension = SharedFileCapabilities.primaryExtensionFor(type) ?: return null
-    return "$bookId.$extension"
+    return sharedCloudBookContentFileName(bookId, type)
 }
 
 private data class DesktopCloudShelfRecord(
@@ -613,18 +1124,53 @@ private fun shouldDownloadRemoteBookContent(local: BookItem, remote: DesktopClou
         ?: localFile?.takeIf { it.isFile }?.lastModified()
         ?: 0L
     return local.sourceFolder == null &&
-        !remote.isDeleted &&
         remote.fileType() == local.type &&
-        remote.fileContentModifiedTimestamp > 0L &&
-        (localFile == null || !localFile.isFile || remote.fileContentModifiedTimestamp > localTimestamp)
+        shouldDownloadRemoteCloudBookContent(
+            localFileAvailable = localFile?.isFile == true,
+            localContentModifiedTimestamp = localTimestamp,
+            remoteContentModifiedTimestamp = remote.fileContentModifiedTimestamp,
+            remoteDeleted = remote.isDeleted
+        )
 }
 
 private fun shouldUploadLocalBookContent(local: BookItem, remote: DesktopCloudBookMetadata?): Boolean {
     val localFile = local.path?.let(::File)?.takeIf { it.isFile } ?: return false
     val localTimestamp = local.fileContentModifiedTimestamp.takeIf { it > 0L } ?: localFile.lastModified()
     return local.sourceFolder == null &&
-        localTimestamp > 0L &&
-        localTimestamp > (remote?.fileContentModifiedTimestamp ?: 0L)
+        shouldUploadLocalCloudBookContent(
+            localFileAvailable = true,
+            localContentModifiedTimestamp = localTimestamp,
+            remoteContentModifiedTimestamp = remote?.fileContentModifiedTimestamp
+        )
+}
+
+private fun shouldUploadLocalAnnotations(
+    local: BookItem,
+    remote: DesktopCloudBookMetadata?,
+    remoteAnnotationModifiedTimestamp: Long = remote?.effectiveCloudAnnotationModifiedTimestamp() ?: 0L,
+    localSidecarTimestamp: Long = DesktopCloudSidecarSync.localAnnotationTimestamp(local)
+): Boolean {
+    return DesktopCloudSidecarSync.hasLocalAnnotationData(local) &&
+        (remote == null || !remote.hasAnnotations || localSidecarTimestamp > remoteAnnotationModifiedTimestamp)
+}
+
+private fun remoteAnnotationDriveFileTimestamp(
+    bookId: String,
+    driveFiles: Map<String, DesktopDriveFile>
+): Long {
+    return driveFiles[desktopCloudAnnotationDriveFileName(bookId)]?.modifiedTimeMillis ?: 0L
+}
+
+internal fun desktopCloudAnnotationDriveFileName(bookId: String): String = "annotation_$bookId.json"
+
+private fun BookItem.withDownloadedCloudContent(downloaded: BookItem?, replacePath: Boolean = true): BookItem {
+    if (downloaded == null) return this
+    return copy(
+        path = if (replacePath) downloaded.path ?: path else path,
+        fileSize = downloaded.fileSize.takeIf { it > 0L } ?: fileSize,
+        fileContentModifiedTimestamp = downloaded.fileContentModifiedTimestamp.takeIf { it > 0L }
+            ?: fileContentModifiedTimestamp
+    )
 }
 
 private fun desktopShelfTimestamp(record: ShelfRecord, refs: List<BookShelfRef>): Long {
@@ -634,17 +1180,7 @@ private fun desktopShelfTimestamp(record: ShelfRecord, refs: List<BookShelfRef>)
 }
 
 private fun ReaderLocator.cloudPositionCfi(): String? {
-    cfi?.let { return it }
-    val chapter = chapterIndex
-    val start = startOffset
-    val end = endOffset ?: start
-    return if (chapter != null && start != null && end != null) {
-        "desktop:$chapter:$start:$end"
-    } else if (chapter != null && pageIndex != null) {
-        "desktop:$chapter:$pageIndex"
-    } else {
-        null
-    }
+    return toStablePositionCfi()
 }
 
 private fun ReaderBookmark.toDesktopCloudEpubBookmarkOrNull(): EpubBookmark? {

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopCloudSyncDiagnostics.kt

@@ -0,0 +1,82 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.BookItem
+import com.aryan.reader.shared.FileType
+import com.aryan.reader.shared.SharedFileCapabilities
+
+internal const val DesktopCloudSyncLogTag = "EpistemeCloudSync"
+internal const val DesktopCloudAnnotationSyncLogTag = "EpistemeCloudAnnotations"
+
+internal fun logDesktopCloudSync(message: () -> String) {
+    logDesktopDiagnostic(DesktopCloudSyncLogTag, message)
+}
+
+internal fun logDesktopCloudAnnotations(message: () -> String) {
+    logDesktopDiagnostic(DesktopCloudAnnotationSyncLogTag, message)
+}
+
+internal fun BookItem.desktopCloudSyncSummary(prefix: String = "local"): String {
+    val position = readerPosition
+    val page = if (type.usesCloudLocatorForDiagnostics()) {
+        position?.pageIndex ?: lastPageIndex
+    } else {
+        lastPageIndex
+    }
+    return "$prefix{id=$id type=$type ts=$timestamp readTs=${effectiveCloudReadingPositionModifiedTimestamp()} " +
+        "contentTs=$fileContentModifiedTimestamp " +
+        "page=$page chapter=${position?.chapterIndex} " +
+        "block=${position?.blockIndex} char=${position?.charOffset} progress=$progressPercentage " +
+        "cfi=${position?.cfi.cloudSyncPreview()} sourceFolder=${sourceFolder != null} " +
+        "bookmarks=${readerBookmarks.size} highlights=${readerHighlights.size}}"
+}
+
+internal fun DesktopCloudBookMetadata.desktopCloudSyncSummary(prefix: String = "remote"): String {
+    return "$prefix{id=$bookId type=$type ts=$lastModifiedTimestamp readTs=${effectiveCloudReadingPositionModifiedTimestamp()} " +
+        "annTs=${effectiveCloudAnnotationModifiedTimestamp()} contentTs=$fileContentModifiedTimestamp " +
+        "page=$lastPage chapter=$lastChapterIndex block=$locatorBlockIndex char=$locatorCharOffset " +
+        "progress=$progressPercentage cfi=${lastPositionCfi.cloudSyncPreview()} deleted=$isDeleted " +
+        "recent=$isRecent hasAnnotations=$hasAnnotations bookmarks=${bookmarksJson.cloudSyncAnnotationSummary()} " +
+        "highlights=${highlightsJson.cloudSyncAnnotationSummary()}}"
+}
+
+internal fun BookItem.hasSameCloudReaderPosition(other: BookItem): Boolean {
+    val thisPage = if (type.usesCloudLocatorForDiagnostics()) readerPosition?.pageIndex ?: lastPageIndex else lastPageIndex
+    val otherPage = if (other.type.usesCloudLocatorForDiagnostics()) {
+        other.readerPosition?.pageIndex ?: other.lastPageIndex
+    } else {
+        other.lastPageIndex
+    }
+    val thisProgress = progressPercentage
+    val otherProgress = other.progressPercentage
+    val progressMatches = when {
+        thisProgress == null && otherProgress == null -> true
+        thisProgress != null && otherProgress != null -> kotlin.math.abs(thisProgress - otherProgress) < 0.001f
+        else -> false
+    }
+    val locatorMatches = if (type.usesCloudLocatorForDiagnostics() || other.type.usesCloudLocatorForDiagnostics()) {
+        readerPosition == other.readerPosition
+    } else {
+        true
+    }
+    return thisPage == otherPage &&
+        locatorMatches &&
+        progressMatches
+}
+
+private fun com.aryan.reader.shared.FileType.usesCloudLocatorForDiagnostics(): Boolean {
+    return this != FileType.PDF && this != FileType.PPTX && !SharedFileCapabilities.isComicArchive(this)
+}
+
+private fun String?.cloudSyncPreview(maxLength: Int = 80): String {
+    val value = this ?: return "null"
+    return if (value.length <= maxLength) value else value.take(maxLength) + "..."
+}
+
+private fun String?.cloudSyncAnnotationSummary(): String {
+    val value = this?.trim() ?: return "null"
+    return when {
+        value.isEmpty() -> "blank"
+        value == "[]" -> "empty"
+        else -> "present(${value.length})"
+    }
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopComicArchive.kt

@@ -1,6 +1,7 @@
 package com.aryan.reader.desktop
 
 import com.aryan.reader.shared.FileType
+import com.aryan.reader.shared.SharedFileCapabilities
 import com.aryan.reader.shared.opds.OpdsCatalog
 import com.aryan.reader.shared.opds.OpdsStreamReference
 import com.sun.jna.Library
@@ -8,8 +9,9 @@ import com.sun.jna.Native
 import com.sun.jna.Pointer
 import com.sun.jna.ptr.PointerByReference
 import org.apache.commons.compress.archivers.sevenz.SevenZFile
-import java.awt.Font
+import org.apache.commons.compress.archivers.tar.TarArchiveInputStream
 import java.awt.Color
+import java.awt.Font
 import java.awt.RenderingHints
 import java.awt.image.BufferedImage
 import java.io.ByteArrayInputStream
@@ -24,7 +26,7 @@ import javax.imageio.ImageIO
 import kotlin.math.roundToInt
 
 internal object DesktopComicArchive {
-    private val comicTypes = setOf(FileType.CBZ, FileType.CBR, FileType.CB7)
+    private val comicTypes = SharedFileCapabilities.comicArchiveTypes
     private val imageExtensions = setOf("jpg", "jpeg", "png", "webp", "bmp", "gif")
 
     fun canLoad(type: FileType): Boolean = type in comicTypes
@@ -36,6 +38,7 @@ internal object DesktopComicArchive {
             FileType.CBZ -> loadZip(file)
             FileType.CBR -> loadRar(file)
             FileType.CB7 -> loadSevenZ(file)
+            FileType.CBT -> loadTar(file)
             else -> error("${type.name} is not a comic archive type.")
         }
     }
@@ -162,6 +165,31 @@ internal object DesktopComicArchive {
             }
     }
 
+    private fun loadTar(file: File): DesktopComicDocument {
+        val tempDir = Files.createTempDirectory("reader-comic-").toFile()
+        return try {
+            val extracted = mutableListOf<ExtractedComicPage>()
+            TarArchiveInputStream(file.inputStream().buffered()).use { archive ->
+                var entry = archive.nextEntry
+                while (entry != null) {
+                    val name = entry.name.orEmpty()
+                    if (!entry.isDirectory && name.isComicImageName()) {
+                        val target = File(tempDir, "page_${extracted.size}.${name.imageExtension()}")
+                        target.outputStream().use { output ->
+                            archive.copyTo(output)
+                        }
+                        extracted += ExtractedComicPage(name = name, file = target)
+                    }
+                    entry = archive.nextEntry
+                }
+            }
+            documentFromExtracted(file, extracted, tempDir)
+        } catch (throwable: Throwable) {
+            runCatching { tempDir.deleteRecursively() }
+            throw throwable
+        }
+    }
+
     private fun loadWithArchiveCommand(file: File): DesktopComicDocument {
         val tempDir = Files.createTempDirectory("reader-comic-").toFile()
         return try {

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopDiagnostics.kt

@@ -1,16 +1,40 @@
 package com.aryan.reader.desktop
 
 internal const val DesktopDiagnosticsProperty = "episteme.desktop.diagnostics"
+private const val DesktopDiagnosticsTagsProperty = "episteme.desktop.diagnostics.tags"
+private const val DesktopDiagnosticsEnv = "EPISTEME_DESKTOP_DIAGNOSTICS"
+private const val DesktopDiagnosticsTagsEnv = "EPISTEME_DESKTOP_DIAGNOSTICS_TAGS"
+
+private val DesktopDiagnosticTags: Set<String> =
+    listOfNotNull(
+        System.getProperty(DesktopDiagnosticsTagsProperty),
+        System.getenv(DesktopDiagnosticsTagsEnv)
+    )
+        .joinToString(" ")
+        .split(',', ';', ' ', '\t', '\n')
+        .mapNotNull { rawTag ->
+            rawTag.trim()
+                .takeIf { it.isNotBlank() }
+                ?.lowercase()
+        }
+        .toSet()
 
 internal val DesktopDiagnosticsEnabled: Boolean =
-    desktopDiagnosticsFlag(System.getProperty(DesktopDiagnosticsProperty))
+    desktopDiagnosticsFlag(System.getProperty(DesktopDiagnosticsProperty)) ||
+        desktopDiagnosticsFlag(System.getenv(DesktopDiagnosticsEnv)) ||
+        DesktopDiagnosticTags.isNotEmpty()
 
 internal fun desktopDiagnosticsFlag(rawValue: String?): Boolean {
     return rawValue?.trim()?.equals("true", ignoreCase = true) == true
 }
 
-internal inline fun logDesktopDiagnostic(tag: String, message: () -> String) {
-    if (DesktopDiagnosticsEnabled) {
+private fun isDesktopDiagnosticTagEnabled(tag: String): Boolean {
+    if (DesktopDiagnosticTags.isEmpty()) return true
+    return "*" in DesktopDiagnosticTags || tag.lowercase() in DesktopDiagnosticTags
+}
+
+internal fun logDesktopDiagnostic(tag: String, message: () -> String) {
+    if (DesktopDiagnosticsEnabled && isDesktopDiagnosticTagEnabled(tag)) {
         println("$tag ${message()}")
     }
 }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopEpubBridgeParsing.kt

@@ -1,6 +1,7 @@
 package com.aryan.reader.desktop
 
 import com.aryan.reader.shared.ReaderLocator
+import com.aryan.reader.shared.toStableReaderPositionCfi
 import com.aryan.reader.shared.ui.SharedNativeReaderLinkClick
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.JsonNull
@@ -46,7 +47,8 @@ internal data class DesktopEpubHandledLink(
 internal enum class DesktopReaderSelectionAction {
     DEFINE,
     SPEAK,
-    SEARCH
+    SEARCH,
+    PALETTE
 }
 
 internal enum class DesktopReaderKeyNavigation {
@@ -59,7 +61,10 @@ internal enum class DesktopReaderKeyNavigation {
     EXIT_FULLSCREEN
 }
 
-internal fun AwtKeyEvent.desktopReaderKeyNavigationOrNull(fullscreen: Boolean): DesktopReaderKeyNavigation? {
+internal fun AwtKeyEvent.desktopReaderKeyNavigationOrNull(
+    fullscreen: Boolean,
+    rightToLeftPagination: Boolean = false
+): DesktopReaderKeyNavigation? {
     if (id != AwtKeyEvent.KEY_PRESSED) return null
     if (fullscreen && keyCode == AwtKeyEvent.VK_ESCAPE) {
         return DesktopReaderKeyNavigation.EXIT_FULLSCREEN
@@ -71,9 +76,17 @@ internal fun AwtKeyEvent.desktopReaderKeyNavigationOrNull(fullscreen: Boolean):
         return DesktopReaderKeyNavigation.NEXT_SEARCH
     }
     return when (keyCode) {
-        AwtKeyEvent.VK_RIGHT,
+        AwtKeyEvent.VK_RIGHT -> if (rightToLeftPagination) {
+            DesktopReaderKeyNavigation.PREVIOUS
+        } else {
+            DesktopReaderKeyNavigation.NEXT
+        }
+        AwtKeyEvent.VK_LEFT -> if (rightToLeftPagination) {
+            DesktopReaderKeyNavigation.NEXT
+        } else {
+            DesktopReaderKeyNavigation.PREVIOUS
+        }
         AwtKeyEvent.VK_PAGE_DOWN -> DesktopReaderKeyNavigation.NEXT
-        AwtKeyEvent.VK_LEFT,
         AwtKeyEvent.VK_PAGE_UP -> DesktopReaderKeyNavigation.PREVIOUS
         AwtKeyEvent.VK_HOME -> DesktopReaderKeyNavigation.FIRST
         AwtKeyEvent.VK_END -> DesktopReaderKeyNavigation.LAST
@@ -83,7 +96,8 @@ internal fun AwtKeyEvent.desktopReaderKeyNavigationOrNull(fullscreen: Boolean):
 
 internal data class DesktopReaderSelectionActionPayload(
     val action: DesktopReaderSelectionAction,
-    val text: String
+    val text: String,
+    val locator: ReaderLocator? = null
 )
 
 internal fun String.readerHighlightClickOrNull(): DesktopReaderHighlightClick? {
@@ -128,9 +142,27 @@ internal fun String.readerSelectionActionOrNull(): DesktopReaderSelectionActionP
             "define" -> DesktopReaderSelectionAction.DEFINE
             "speak" -> DesktopReaderSelectionAction.SPEAK
             "web-search", "search" -> DesktopReaderSelectionAction.SEARCH
+            "palette" -> DesktopReaderSelectionAction.PALETTE
             else -> return@runCatching null
         }
-        DesktopReaderSelectionActionPayload(action, text)
+        val locator = obj["locator"]
+            ?.takeUnless { it is JsonNull }
+            ?.jsonObject
+            ?.let { locatorObj ->
+                ReaderLocator(
+                    chapterIndex = locatorObj["chapterIndex"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull,
+                    chapterId = locatorObj["chapterId"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.contentOrNull,
+                    href = locatorObj["href"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.contentOrNull,
+                    pageIndex = locatorObj["pageIndex"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull,
+                    startOffset = locatorObj["startOffset"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull,
+                    endOffset = locatorObj["endOffset"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull,
+                    blockIndex = locatorObj["blockIndex"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull,
+                    charOffset = locatorObj["charOffset"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull,
+                    textQuote = locatorObj["textQuote"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.contentOrNull,
+                    cfi = locatorObj["cfi"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.contentOrNull?.toStableReaderPositionCfi()
+                )
+            }
+        DesktopReaderSelectionActionPayload(action, text, locator)
     }.getOrNull()
 
     parse(this)?.let { return it }
@@ -181,11 +213,15 @@ internal fun String.readerPositionOrNull(): DesktopReaderPosition? {
             ?: return@runCatching null
         val locator = ReaderLocator(
             chapterIndex = obj["chapterIndex"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull,
+            chapterId = obj["chapterId"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.contentOrNull,
+            href = obj["href"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.contentOrNull,
             pageIndex = pageIndex,
             startOffset = obj["startOffset"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull,
             endOffset = obj["endOffset"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull,
+            blockIndex = obj["blockIndex"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull,
+            charOffset = obj["charOffset"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull,
             textQuote = obj["textQuote"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.contentOrNull,
-            cfi = obj["cfi"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.contentOrNull
+            cfi = obj["cfi"]?.takeUnless { it is JsonNull }?.jsonPrimitive?.contentOrNull?.toStableReaderPositionCfi()
         )
         DesktopReaderPosition(pageIndex, locator)
     }.getOrNull()
@@ -284,9 +320,7 @@ private fun String.readerHrefFromIntercept(): String? {
     val trimmed = trim()
     if (trimmed.isBlank()) return null
     if (trimmed.equals("about:blank", ignoreCase = true)) return null
-    if (trimmed.startsWith("file:///kcefbrowser/", ignoreCase = true)) return null
-    if (trimmed.startsWith("file:/kcefbrowser/", ignoreCase = true)) return null
-    if (trimmed.startsWith("file://", ignoreCase = true)) return null
+    if (trimmed.startsWith("file:/", ignoreCase = true)) return null
     if (trimmed.startsWith("about:blank#", ignoreCase = true)) return "#${trimmed.substringAfter('#')}"
     if (trimmed.startsWith("data:", ignoreCase = true)) return null
     if (trimmed.startsWith("blob:", ignoreCase = true)) return null
@@ -298,9 +332,13 @@ internal fun ReaderLocator.toReaderLocatorJson(): String {
         append("{")
         val values = buildList {
             chapterIndex?.let { add("\"chapterIndex\":$it") }
+            chapterId?.let { add("\"chapterId\":${it.toJsonStringLiteral()}") }
+            href?.let { add("\"href\":${it.toJsonStringLiteral()}") }
             pageIndex?.let { add("\"pageIndex\":$it") }
             startOffset?.let { add("\"startOffset\":$it") }
             endOffset?.let { add("\"endOffset\":$it") }
+            blockIndex?.let { add("\"blockIndex\":$it") }
+            charOffset?.let { add("\"charOffset\":$it") }
             cfi?.let { add("\"cfi\":${it.toJsonStringLiteral()}") }
             textQuote?.let { add("\"textQuote\":${it.toJsonStringLiteral()}") }
         }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopEpubPagination.kt

@@ -11,6 +11,8 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.unit.dp
 import com.aryan.reader.shared.reader.ReaderLayoutSignature
+import com.aryan.reader.shared.reader.ReaderPage
+import com.aryan.reader.shared.reader.ReaderReadingMode
 import com.aryan.reader.shared.reader.ReaderViewportSpec
 import com.aryan.reader.shared.reader.SharedEpubBook
 
@@ -28,6 +30,44 @@ internal data class DesktopEpubPaginationDensity(
     val fontScale: Float
 )
 
+internal fun desktopMeasuredPaginationReady(
+    request: DesktopEpubPaginationRequest?,
+    completedRequest: DesktopEpubPaginationRequest?,
+    currentPages: List<ReaderPage>,
+    measuredPages: List<ReaderPage>
+): Boolean {
+    return request != null &&
+        completedRequest == request &&
+        measuredPages.isNotEmpty() &&
+        currentPages.samePageLayoutAs(measuredPages)
+}
+
+internal fun desktopPaginatedLayoutReadyForDisplay(
+    readingMode: ReaderReadingMode,
+    measuredPagesApplied: Boolean
+): Boolean {
+    return readingMode != ReaderReadingMode.PAGINATED || measuredPagesApplied
+}
+
+internal fun desktopPagesWithMeasuredChapter(
+    currentPages: List<ReaderPage>,
+    chapterIndex: Int,
+    measuredChapterPages: List<ReaderPage>
+): List<ReaderPage> {
+    if (currentPages.isEmpty() || measuredChapterPages.isEmpty()) return currentPages
+    val firstChapterPage = currentPages.indexOfFirst { it.chapterIndex == chapterIndex }
+    if (firstChapterPage < 0) return currentPages
+    val lastChapterPage = currentPages.indexOfLast { it.chapterIndex == chapterIndex }
+    val combined = currentPages.take(firstChapterPage) +
+        measuredChapterPages +
+        currentPages.drop(lastChapterPage + 1)
+    return combined.mapIndexed { index, page -> page.copy(pageIndex = index) }
+}
+
+internal fun List<ReaderPage>.firstPageIndexForChapter(chapterIndex: Int): Int? {
+    return indexOfFirst { it.chapterIndex == chapterIndex }.takeIf { it >= 0 }
+}
+
 internal fun SharedEpubBook.desktopPaginationContentSignature(): Int {
     return chapters.fold(31 * id.hashCode() + css.hashCode()) { acc, chapter ->
         31 * acc +

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopEpubWebView.kt

@@ -1,57 +1,85 @@
 package com.aryan.reader.desktop
 
-import androidx.compose.foundation.layout.Box
-import androidx.compose.foundation.layout.fillMaxSize
-import androidx.compose.foundation.layout.fillMaxWidth
-import androidx.compose.material3.LinearProgressIndicator
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.rememberUpdatedState
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
 import com.aryan.reader.shared.EpubAnnotationSerializer
 import com.aryan.reader.shared.ReaderLocator
 import com.aryan.reader.shared.UserHighlight
-import com.aryan.reader.shared.reader.ReaderReadingMode
 import com.aryan.reader.shared.ui.ReaderContentNavigationTarget
-import com.multiplatform.webview.jsbridge.IJsMessageHandler
-import com.multiplatform.webview.jsbridge.JsMessage
-import com.multiplatform.webview.jsbridge.rememberWebViewJsBridge
-import com.multiplatform.webview.request.RequestInterceptor
-import com.multiplatform.webview.request.WebRequest
-import com.multiplatform.webview.request.WebRequestInterceptResult
-import com.multiplatform.webview.web.LoadingState
-import com.multiplatform.webview.web.WebContent
-import com.multiplatform.webview.web.WebView
-import com.multiplatform.webview.web.WebViewNavigator
-import com.multiplatform.webview.web.WebViewState
-import com.multiplatform.webview.web.rememberWebViewNavigator
 import kotlinx.coroutines.launch
-import java.awt.AWTEvent
-import java.awt.Toolkit
-import java.awt.event.AWTEventListener
-import java.awt.event.MouseEvent
 
 @Composable
 internal fun DesktopEpubWebView(
     html: String,
     appearanceScript: String,
+    highlightPaletteScript: String,
     navigationTarget: ReaderContentNavigationTarget,
     highlights: List<UserHighlight>,
     onHighlightCreated: (UserHighlight) -> Unit,
     onHighlightSelected: (String) -> Unit,
     isFullscreen: Boolean,
     onKeyboardNavigation: (DesktopReaderKeyNavigation) -> Unit,
-    onSelectionAction: (DesktopReaderSelectionAction, String) -> Unit,
+    onSelectionAction: (DesktopReaderSelectionActionPayload) -> Unit,
     onLinkClicked: (DesktopEpubLinkClick) -> Unit,
     onVisiblePageChanged: (Int, ReaderLocator?) -> Unit,
     onPointerActivity: () -> Unit = {},
     networkAccessEnabled: Boolean,
+    backgroundColor: Color,
     modifier: Modifier = Modifier
 ) {
+    val backend = desktopEpubWebViewBackend()
+    LaunchedEffect(html, networkAccessEnabled, highlights.size, navigationTarget.readingMode, backend) {
+        logDesktopWebView2(
+            "backend_selected backend=${backend.logName} htmlChars=${html.length} htmlHash=${html.hashCode()} " +
+                "network=$networkAccessEnabled highlights=${highlights.size} navMode=${navigationTarget.readingMode}"
+        )
+        logDesktopReaderOpenTrace {
+            "event=desktop_webview_selected backend=${backend.logName} htmlChars=${html.length} " +
+                "htmlHash=${html.hashCode()} network=$networkAccessEnabled highlights=${highlights.size} " +
+                "navMode=${navigationTarget.readingMode}"
+        }
+    }
+    DesktopNativeSwtEpubWebView(
+        html = html,
+        appearanceScript = appearanceScript,
+        highlightPaletteScript = highlightPaletteScript,
+        navigationTarget = navigationTarget,
+        highlights = highlights,
+        onHighlightCreated = onHighlightCreated,
+        onHighlightSelected = onHighlightSelected,
+        isFullscreen = isFullscreen,
+        onKeyboardNavigation = onKeyboardNavigation,
+        onSelectionAction = onSelectionAction,
+        onLinkClicked = onLinkClicked,
+        onVisiblePageChanged = onVisiblePageChanged,
+        onPointerActivity = onPointerActivity,
+        networkAccessEnabled = networkAccessEnabled,
+        backgroundColor = backgroundColor,
+        modifier = modifier
+    )
+}
+
+internal data class DesktopEpubBridgeHandler(
+    val methodName: String,
+    val onMessage: (String) -> Unit
+)
+
+@Composable
+internal fun rememberDesktopEpubBridgeHandlers(
+    onHighlightCreated: (UserHighlight) -> Unit,
+    onHighlightSelected: (String) -> Unit,
+    onKeyboardNavigation: (DesktopReaderKeyNavigation) -> Unit,
+    onSelectionAction: (DesktopReaderSelectionActionPayload) -> Unit,
+    onLinkClicked: (DesktopEpubLinkClick) -> Unit,
+    onVisiblePageChanged: (Int, ReaderLocator?) -> Unit,
+    onPointerActivity: () -> Unit
+): List<DesktopEpubBridgeHandler> {
     val latestOnHighlightCreated by rememberUpdatedState(onHighlightCreated)
     val latestOnHighlightSelected by rememberUpdatedState(onHighlightSelected)
     val latestOnKeyboardNavigation by rememberUpdatedState(onKeyboardNavigation)
@@ -60,81 +88,98 @@ internal fun DesktopEpubWebView(
     val latestOnVisiblePageChanged by rememberUpdatedState(onVisiblePageChanged)
     val latestOnPointerActivity by rememberUpdatedState(onPointerActivity)
     val scope = rememberCoroutineScope()
-    val linkRequestInterceptor = remember(scope, networkAccessEnabled) {
-        object : RequestInterceptor {
-            override fun onInterceptUrlRequest(
-                request: WebRequest,
-                navigator: WebViewNavigator
-            ): WebRequestInterceptResult {
-                if (!networkAccessEnabled && request.url.isRemoteNetworkUrl()) {
-                    logEpubLink("request_blocked_offline url=\"${request.url.logPreview()}\"")
-                    return WebRequestInterceptResult.Reject
-                }
-                if (!request.isForMainFrame) return WebRequestInterceptResult.Allow
-                val link = request.url.readerLinkClickFromIntercept() ?: return WebRequestInterceptResult.Allow
-                logEpubLink(
-                    "request_intercept method=${request.method} redirect=${request.isRedirect} " +
-                        "url=\"${request.url.logPreview()}\" href=\"${link.href.logPreview()}\""
-                )
-                scope.launch {
-                    latestOnLinkClicked(link.copy(source = "request"))
-                }
-                return WebRequestInterceptResult.Reject
-            }
-        }
-    }
-    val navigator = rememberWebViewNavigator(requestInterceptor = linkRequestInterceptor)
-    val bridge = rememberWebViewJsBridge()
-
-    DisposableEffect(bridge) {
-        val handlers = listOf(
-            desktopEpubBridgeHandler("readerHighlightCreated") { message ->
-                val highlight = EpubAnnotationSerializer.parseHighlightJsonLenient(message.params)
+    return remember(scope) {
+        listOf(
+            DesktopEpubBridgeHandler("readerHighlightCreated") { params ->
+                logEpubHighlightFlow("bridge_received method=readerHighlightCreated params=\"${params.logPreview(900)}\"")
+                val highlight = EpubAnnotationSerializer.parseHighlightJsonLenient(params)
                 if (highlight == null) {
-                    logEpubSelectionDebug("highlight_parse_failed params=${message.params.logPreview(900)}")
+                    logEpubHighlightFlow("bridge_parse_failed method=readerHighlightCreated")
+                    logEpubSelectionDebug("highlight_parse_failed params=${params.logPreview(900)}")
                 } else {
+                    logEpubHighlightFlow(
+                        "bridge_parse_success id=${highlight.id} color=${highlight.color.id} " +
+                            "chapter=${highlight.chapterIndex} offsets=${highlight.locator.startOffset}..${highlight.locator.endOffset} " +
+                            "page=${highlight.locator.pageIndex} textChars=${highlight.text.length} cfi=\"${highlight.cfi.logPreview()}\""
+                    )
+                    logDesktopHighlightMap(
+                        "bridge_highlight_created id=${highlight.id} color=${highlight.color.id} " +
+                            "chapter=${highlight.chapterIndex} locatorChapter=${highlight.locator.chapterIndex} " +
+                            "page=${highlight.locator.pageIndex} offsets=${highlight.locator.startOffset}..${highlight.locator.endOffset} " +
+                            "block=${highlight.locator.blockIndex} char=${highlight.locator.charOffset} " +
+                            "chapterId=${highlight.locator.chapterId.orEmpty().logPreview()} href=${highlight.locator.href.orEmpty().logPreview()} " +
+                            "textChars=${highlight.text.length} cfi=\"${highlight.cfi.logPreview()}\""
+                    )
                     scope.launch { latestOnHighlightCreated(highlight) }
                 }
             },
-            desktopEpubBridgeHandler("readerHighlightClicked") { message ->
-                message.params.readerHighlightClickOrNull()?.let { highlightClick ->
+            DesktopEpubBridgeHandler("readerHighlightClicked") { params ->
+                params.readerHighlightClickOrNull()?.let { highlightClick ->
                     scope.launch { latestOnHighlightSelected(highlightClick.highlightId) }
                 }
             },
-            desktopEpubBridgeHandler("readerPositionChanged") { message ->
-                message.params.readerPositionOrNull()?.let { position ->
+            DesktopEpubBridgeHandler("readerPositionChanged") { params ->
+                params.readerPositionOrNull()?.let { position ->
+                    logDesktopPositionTrace(
+                        "event=bridge_position_changed page=${position.pageIndex} " +
+                            "locator=${position.locator.desktopPositionTraceSummary()}"
+                    )
+                    logDesktopHighlightMap(
+                        "bridge_position_changed page=${position.pageIndex} chapter=${position.locator?.chapterIndex} " +
+                            "offsets=${position.locator?.startOffset}..${position.locator?.endOffset} " +
+                            "block=${position.locator?.blockIndex} char=${position.locator?.charOffset} " +
+                            "chapterId=${position.locator?.chapterId.orEmpty().logPreview()} href=${position.locator?.href.orEmpty().logPreview()} " +
+                            "text=\"${position.locator?.textQuote.orEmpty().logPreview(120)}\" " +
+                            "cfi=\"${position.locator?.cfi.orEmpty().logPreview(160)}\""
+                    )
+                    logDesktopTtsStartTrace {
+                        "event=bridge_position_changed page=${position.pageIndex} " +
+                            "locator=${position.locator.desktopPositionTraceSummary(160)}"
+                    }
                     scope.launch { latestOnVisiblePageChanged(position.pageIndex, position.locator) }
                 }
             },
-            desktopEpubBridgeHandler("readerSelectionAction") { message ->
-                val selectionAction = message.params.readerSelectionActionOrNull()
+            DesktopEpubBridgeHandler("readerDesktopPositionTraceLog") { params ->
+                logDesktopPositionTrace(params.readerSelectionDebugMessageOrNull() ?: params.logPreview(900))
+            },
+            DesktopEpubBridgeHandler("readerTtsStartTraceLog") { params ->
+                logDesktopTtsStartTrace { params.readerSelectionDebugMessageOrNull() ?: params.logPreview(900) }
+            },
+            DesktopEpubBridgeHandler("readerSelectionAction") { params ->
+                val selectionAction = params.readerSelectionActionOrNull()
                 if (selectionAction != null) {
-                    scope.launch { latestOnSelectionAction(selectionAction.action, selectionAction.text) }
+                    scope.launch { latestOnSelectionAction(selectionAction) }
                 }
             },
-            desktopEpubBridgeHandler("readerKeyNavigation") { message ->
-                message.params.readerKeyNavigationOrNull()?.let { action ->
+            DesktopEpubBridgeHandler("readerKeyNavigation") { params ->
+                params.readerKeyNavigationOrNull()?.let { action ->
                     scope.launch { latestOnKeyboardNavigation(action) }
                 }
             },
-            desktopEpubBridgeHandler("readerPointerActivity") { _ ->
+            DesktopEpubBridgeHandler("readerPointerActivity") {
                 scope.launch { latestOnPointerActivity() }
             },
-            desktopEpubBridgeHandler("readerTtsHighlightLog") { message ->
-                logDesktopTts("epub_highlight_js ${message.params.logPreview(500)}")
+            DesktopEpubBridgeHandler("readerTtsHighlightLog") { params ->
+                logDesktopTts("epub_highlight_js ${params.logPreview(500)}")
             },
-            desktopEpubBridgeHandler("readerSelectionDebugLog") { message ->
-                logEpubSelectionDebug(message.params.readerSelectionDebugMessageOrNull() ?: message.params.logPreview(900))
+            DesktopEpubBridgeHandler("readerSelectionDebugLog") { params ->
+                logEpubSelectionDebug(params.readerSelectionDebugMessageOrNull() ?: params.logPreview(900))
             },
-            desktopEpubBridgeHandler("readerPaginationLayoutLog") { message ->
-                logEpubPagination(message.params.readerPaginationLogMessageOrNull() ?: message.params.logPreview(900))
+            DesktopEpubBridgeHandler("readerHighlightFlowLog") { params ->
+                logEpubHighlightFlow(params.readerSelectionDebugMessageOrNull() ?: params.logPreview(900))
             },
-            desktopEpubBridgeHandler("readerGapLayoutLog") { message ->
-                logReaderGap(message.params.readerPaginationLogMessageOrNull() ?: message.params.logPreview(900))
+            DesktopEpubBridgeHandler("readerDesktopHighlightMapLog") { params ->
+                logDesktopHighlightMap(params.readerSelectionDebugMessageOrNull() ?: params.logPreview(900))
             },
-            desktopEpubBridgeHandler("readerLinkClicked") { message ->
-                logEpubLink("bridge_message params=\"${message.params.logPreview()}\"")
-                val link = message.params.readerLinkClickOrNull()
+            DesktopEpubBridgeHandler("readerPaginationLayoutLog") { params ->
+                logEpubPagination(params.readerPaginationLogMessageOrNull() ?: params.logPreview(900))
+            },
+            DesktopEpubBridgeHandler("readerGapLayoutLog") { params ->
+                logReaderGap(params.readerPaginationLogMessageOrNull() ?: params.logPreview(900))
+            },
+            DesktopEpubBridgeHandler("readerLinkClicked") { params ->
+                logEpubLink("bridge_message params=\"${params.logPreview()}\"")
+                val link = params.readerLinkClickOrNull()
                 if (link == null) {
                     logEpubLink("bridge_message_ignored reason=parse_failed")
                 } else {
@@ -146,214 +191,70 @@ internal fun DesktopEpubWebView(
                 }
             }
         )
-        handlers.forEach { bridge.register(it) }
-        onDispose {
-            handlers.forEach { bridge.unregister(it) }
-        }
-    }
-
-    val state = remember {
-        WebViewState(
-            WebContent.Data(
-                data = html,
-                baseUrl = null,
-                encoding = "utf-8",
-                mimeType = "text/html",
-                historyUrl = null
-            )
-        )
-    }
-
-    LaunchedEffect(html) {
-        navigator.loadHtml(
-            html = html,
-            baseUrl = null,
-            mimeType = "text/html",
-            encoding = "utf-8",
-            historyUrl = null
-        )
-    }
-
-    DisposableEffect(Unit) {
-        var lastActivityAt = 0L
-        var lastMouseX: Int? = null
-        var lastMouseY: Int? = null
-        val listener = AWTEventListener { event ->
-            val mouseEvent = event as? MouseEvent ?: return@AWTEventListener
-            if (
-                mouseEvent.id != MouseEvent.MOUSE_MOVED &&
-                mouseEvent.id != MouseEvent.MOUSE_DRAGGED &&
-                mouseEvent.id != MouseEvent.MOUSE_PRESSED &&
-                mouseEvent.id != MouseEvent.MOUSE_WHEEL
-            ) {
-                return@AWTEventListener
-            }
-            if (mouseEvent.id == MouseEvent.MOUSE_MOVED || mouseEvent.id == MouseEvent.MOUSE_DRAGGED) {
-                val screenX = mouseEvent.xOnScreen
-                val screenY = mouseEvent.yOnScreen
-                if (lastMouseX == screenX && lastMouseY == screenY) return@AWTEventListener
-                lastMouseX = screenX
-                lastMouseY = screenY
-            } else {
-                lastMouseX = mouseEvent.xOnScreen
-                lastMouseY = mouseEvent.yOnScreen
-            }
-            val now = mouseEvent.`when`.takeIf { it > 0L } ?: System.currentTimeMillis()
-            if (now - lastActivityAt < 120L) return@AWTEventListener
-            lastActivityAt = now
-            scope.launch { latestOnPointerActivity() }
-        }
-        val eventMask = AWTEvent.MOUSE_MOTION_EVENT_MASK or
-            AWTEvent.MOUSE_EVENT_MASK or
-            AWTEvent.MOUSE_WHEEL_EVENT_MASK
-        Toolkit.getDefaultToolkit().addAWTEventListener(listener, eventMask)
-        onDispose {
-            Toolkit.getDefaultToolkit().removeAWTEventListener(listener)
-        }
-    }
-
-    Box(modifier = modifier) {
-        WebView(
-            state = state,
-            modifier = Modifier.fillMaxSize(),
-            captureBackPresses = false,
-            navigator = navigator,
-            webViewJsBridge = bridge
-        )
-
-        LaunchedEffect(state.loadingState) {
-            if (!state.loadingState.isFinished()) return@LaunchedEffect
-            navigator.evaluateJavaScript(DesktopEpubKeyNavigationScript)
-        }
-
-        LaunchedEffect(isFullscreen, state.loadingState) {
-            if (!state.loadingState.isFinished()) return@LaunchedEffect
-            navigator.evaluateJavaScript("window.readerDesktopFullscreen = ${if (isFullscreen) "true" else "false"};")
-        }
-
-        LaunchedEffect(html, state.loadingState) {
-            if (!state.loadingState.isFinished()) return@LaunchedEffect
-            navigator.evaluateJavaScript("window.readerPaginationLayoutLog && window.readerPaginationLayoutLog('desktop_finished');")
-        }
-
-        LaunchedEffect(appearanceScript, state.loadingState) {
-            if (!state.loadingState.isFinished()) return@LaunchedEffect
-            navigator.evaluateJavaScript(appearanceScript)
-        }
-
-        LaunchedEffect(
-            navigationTarget.autoScroll,
-            navigationTarget.readingMode,
-            state.loadingState
-        ) {
-            if (navigationTarget.readingMode != ReaderReadingMode.VERTICAL) return@LaunchedEffect
-            if (!state.loadingState.isFinished()) return@LaunchedEffect
-            val autoScroll = navigationTarget.autoScroll.sanitized()
-            val command = if (autoScroll.enabled) {
-                "window.readerAutoScroll && window.readerAutoScroll.start(${autoScroll.speed});"
-            } else {
-                "window.readerAutoScroll && window.readerAutoScroll.stop();"
-            }
-            navigator.evaluateJavaScript(command)
-        }
-
-        LaunchedEffect(
-            navigationTarget.requestId,
-            navigationTarget.readingMode,
-            state.loadingState
-        ) {
-            if (navigationTarget.readingMode != ReaderReadingMode.VERTICAL) return@LaunchedEffect
-            if (!state.loadingState.isFinished()) return@LaunchedEffect
-            val locator = navigationTarget.locator ?: return@LaunchedEffect
-            navigator.evaluateJavaScript("window.readerScrollToLocator && window.readerScrollToLocator(${locator.toReaderLocatorJson()});")
-        }
-
-        LaunchedEffect(
-            navigationTarget.ttsRequestId,
-            navigationTarget.ttsLocator,
-            navigationTarget.readingMode,
-            state.loadingState
-        ) {
-            if (!state.loadingState.isFinished()) return@LaunchedEffect
-            val locator = navigationTarget.ttsLocator
-            val command = if (locator == null) {
-                logDesktopTts(
-                    "epub_highlight_command clear mode=${navigationTarget.readingMode} request=${navigationTarget.ttsRequestId}"
-                )
-                "window.readerSetTtsLocator && window.readerSetTtsLocator(null, false);"
-            } else {
-                val follow = navigationTarget.readingMode == ReaderReadingMode.VERTICAL
-                logDesktopTts(
-                    "epub_highlight_command set mode=${navigationTarget.readingMode} request=${navigationTarget.ttsRequestId} " +
-                        "follow=$follow chapter=${locator.chapterIndex} page=${locator.pageIndex} " +
-                        "offsets=${locator.startOffset}..${locator.endOffset} cfi=\"${locator.cfi.orEmpty().logPreview()}\" " +
-                        "text=\"${locator.textQuote.orEmpty().logPreview()}\""
-                )
-                "window.readerSetTtsLocator && window.readerSetTtsLocator(${locator.toReaderLocatorJson()}, $follow);"
-            }
-            navigator.evaluateJavaScript(command)
-        }
-
-        LaunchedEffect(highlights, state.loadingState) {
-            if (!state.loadingState.isFinished()) return@LaunchedEffect
-            val highlightsJson = EpubAnnotationSerializer.highlightsToJson(highlights)
-            navigator.evaluateJavaScript("window.readerApplyHighlights && window.readerApplyHighlights($highlightsJson);")
-        }
-
-        val loadingState = state.loadingState
-        if (loadingState is LoadingState.Loading) {
-            LinearProgressIndicator(
-                progress = { loadingState.progress },
-                modifier = Modifier.fillMaxWidth()
-            )
-        }
     }
 }
 
-private fun desktopEpubBridgeHandler(
-    methodName: String,
-    onMessage: (JsMessage) -> Unit
-): IJsMessageHandler {
-    return object : IJsMessageHandler {
-        override fun methodName(): String = methodName
-
-        override fun handle(
-            message: JsMessage,
-            navigator: WebViewNavigator?,
-            callback: (String) -> Unit
-        ) {
-            onMessage(message)
-        }
-    }
-}
-
-private fun LoadingState.isFinished(): Boolean = this is LoadingState.Finished
-
-private val DesktopEpubKeyNavigationScript = """
+internal val DesktopEpubKeyNavigationScript = """
     (function () {
-      if (!window.readerDesktopPointerActivityInstalled) {
-        window.readerDesktopPointerActivityInstalled = true;
-        var lastPointerActivityAt = 0;
-        var lastPointerX = null;
-        var lastPointerY = null;
-        function notifyPointerActivity(event, requireMovement) {
-          if (requireMovement && event) {
-            var x = Math.round(event.screenX || event.clientX || 0);
-            var y = Math.round(event.screenY || event.clientY || 0);
-            if (lastPointerX === x && lastPointerY === y) return;
-            lastPointerX = x;
-            lastPointerY = y;
-          }
-          var now = Date.now();
-          if (now - lastPointerActivityAt < 120) return;
-          lastPointerActivityAt = now;
+      if (!window.readerDesktopChromeTapInstalled) {
+        window.readerDesktopChromeTapInstalled = true;
+        var chromeTapStart = null;
+        var lastChromeTapNotifiedAt = 0;
+        function notifyChromeTap() {
           if (!window.kmpJsBridge || !window.kmpJsBridge.callNative) return;
           window.kmpJsBridge.callNative('readerPointerActivity', '{}');
+          lastChromeTapNotifiedAt = Date.now();
         }
-        document.addEventListener('mousemove', function (event) { notifyPointerActivity(event, true); }, true);
-        document.addEventListener('pointermove', function (event) { notifyPointerActivity(event, true); }, true);
-        document.addEventListener('pointerdown', function (event) { notifyPointerActivity(event, false); }, true);
-        document.addEventListener('wheel', function (event) { notifyPointerActivity(event, false); }, true);
+        function chromeTapIgnored(target) {
+          if (!target || !target.closest) return false;
+          return !!target.closest(
+            'a[href], button, input, textarea, select, [contenteditable="true"], #reader-selection-menu, .reader-selection-handle'
+          );
+        }
+        function hasActiveReaderSelection() {
+          var selection = window.getSelection && window.getSelection();
+          return !!selection && selection.toString().trim().length > 0;
+        }
+        function beginChromeTap(event) {
+          if (event.button !== undefined && event.button !== 0) return;
+          if (chromeTapIgnored(event.target)) {
+            chromeTapStart = null;
+            return;
+          }
+          chromeTapStart = {
+            pointerId: event.pointerId,
+            x: event.clientX || 0,
+            y: event.clientY || 0,
+            at: Date.now()
+          };
+        }
+        function finishChromeTap(event) {
+          if (!chromeTapStart) return;
+          if (event.pointerId !== undefined && chromeTapStart.pointerId !== undefined && event.pointerId !== chromeTapStart.pointerId) return;
+          var dx = (event.clientX || 0) - chromeTapStart.x;
+          var dy = (event.clientY || 0) - chromeTapStart.y;
+          var elapsed = Date.now() - chromeTapStart.at;
+          chromeTapStart = null;
+          if ((dx * dx + dy * dy) > 64 || elapsed > 650) return;
+          if (chromeTapIgnored(event.target) || hasActiveReaderSelection()) return;
+          notifyChromeTap();
+        }
+        function maybeNotifyChromeTapFromClick(event) {
+          if (Date.now() - lastChromeTapNotifiedAt < 250) return;
+          if (chromeTapIgnored(event.target) || hasActiveReaderSelection()) return;
+          notifyChromeTap();
+        }
+        document.addEventListener('pointerdown', beginChromeTap, true);
+        document.addEventListener('pointerup', finishChromeTap, true);
+        document.addEventListener('pointercancel', function () { chromeTapStart = null; }, true);
+        document.addEventListener('click', function (event) {
+          if (window.PointerEvent) {
+            maybeNotifyChromeTapFromClick(event);
+            return;
+          }
+          beginChromeTap(event);
+          finishChromeTap(event);
+        }, true);
       }
       if (window.readerDesktopKeyNavigationInstalled) return;
       window.readerDesktopKeyNavigationInstalled = true;

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopFeatureNoticePlacement.kt

@@ -0,0 +1,13 @@
+package com.aryan.reader.desktop
+
+internal data class DesktopFeatureNoticePlacement(
+    val readerWindowId: String? = null
+) {
+    fun rendersInMainWindow(): Boolean = readerWindowId == null
+
+    fun rendersInReaderWindow(windowId: String): Boolean = readerWindowId == windowId
+}
+
+internal fun desktopFeatureNoticePlacement(readerWindowId: String?): DesktopFeatureNoticePlacement {
+    return DesktopFeatureNoticePlacement(readerWindowId = readerWindowId?.takeIf { it.isNotBlank() })
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopFirebaseAuthRepository.kt

@@ -68,7 +68,7 @@ internal class DesktopFirebaseAuthRepository(
             googleAccessTokenExpiresAtEpochMillis = googleTokens.expiresAtEpochMillis
         )
         session = nextSession
-        store.save(nextSession)
+        persistSession(nextSession)
         return nextSession
     }
 
@@ -86,24 +86,30 @@ internal class DesktopFirebaseAuthRepository(
         val current = session ?: store.load()?.also { session = it } ?: return null
         if (current.isGoogleAccessTokenFresh) return current.googleAccessToken
         if (current.googleRefreshToken.isBlank()) return null
-        return runCatching {
+        val refreshed = runCatching {
             refreshGoogleAccessToken(current)
-        }.onSuccess { refreshed ->
-            session = refreshed
-            store.save(refreshed)
-        }.getOrNull()?.googleAccessToken
+        }.getOrNull() ?: return null
+        session = refreshed
+        persistSession(refreshed)
+        return refreshed.googleAccessToken
     }
 
     private suspend fun refreshSessionIfNeeded(current: DesktopAuthSession): DesktopAuthSession? {
         if (current.isFresh) return current
-        return runCatching {
+        val refreshed = runCatching {
             refreshFirebaseSession(current)
-        }.onSuccess { refreshed ->
-            session = refreshed
-            store.save(refreshed)
         }.onFailure {
             signOut()
-        }.getOrNull()
+        }.getOrNull() ?: return null
+        session = refreshed
+        persistSession(refreshed)
+        return refreshed
+    }
+
+    private suspend fun persistSession(session: DesktopAuthSession) {
+        withContext(Dispatchers.IO) {
+            store.save(session)
+        }
     }
 
     private suspend fun requestGoogleOAuthCode(openUrl: (String) -> Unit): DesktopOAuthCode = withContext(Dispatchers.IO) {
@@ -364,24 +370,19 @@ internal class DesktopAuthStore(
     }
 
     fun save(session: DesktopAuthSession) {
+        val protectedRefreshToken = protectRequired(RefreshTokenKey, session.refreshToken)
+        val protectedGoogleRefreshToken = session.googleRefreshToken
+            .takeIf { it.isNotBlank() }
+            ?.let { protectRequired(GoogleRefreshTokenKey, it) }
         val properties = Properties().apply {
             setProperty("uid", session.user.uid)
             setProperty("displayName", session.user.displayName.orEmpty())
             setProperty("photoUrl", session.user.photoUrl.orEmpty())
             setProperty("email", session.user.email.orEmpty())
-            runCatching { secretCodec.protect(RefreshTokenKey, session.refreshToken) }
-                .getOrNull()
-                ?.takeIf { it.isNotBlank() }
-                ?.let { setProperty(RefreshTokenKey, it) }
-            runCatching { secretCodec.protect(GoogleRefreshTokenKey, session.googleRefreshToken) }
-                .getOrNull()
-                ?.takeIf { it.isNotBlank() }
-                ?.let { setProperty(GoogleRefreshTokenKey, it) }
-        }
-        settingsFile.parentFile?.mkdirs()
-        settingsFile.outputStream().use { output ->
-            properties.store(output, "Episteme desktop account")
+            setProperty(RefreshTokenKey, protectedRefreshToken)
+            protectedGoogleRefreshToken?.let { setProperty(GoogleRefreshTokenKey, it) }
         }
+        settingsFile.storePropertiesAtomically(properties, "Episteme desktop account")
     }
 
     fun clear() {
@@ -394,6 +395,17 @@ internal class DesktopAuthStore(
         const val RefreshTokenKey = "firebaseRefreshTokenProtected"
         const val GoogleRefreshTokenKey = "googleRefreshTokenProtected"
     }
+
+    private fun protectRequired(keyName: String, value: String): String {
+        if (value.isBlank()) {
+            throw IllegalArgumentException("Cannot save a desktop account without a refresh token.")
+        }
+        val protectedValue = secretCodec.protect(keyName, value)
+        if (protectedValue.isBlank()) {
+            throw IllegalStateException("Desktop secure key storage returned an empty value for $keyName.")
+        }
+        return protectedValue
+    }
 }
 
 private val DesktopAuthJson = Json { ignoreUnknownKeys = true }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopFolderMetadataExtractor.kt

@@ -59,6 +59,16 @@ object DesktopFolderMetadataExtractor {
         return enrichBooks(books) { book -> book.sourceFolder == sourceFolder }
     }
 
+    fun enrichFolderBooks(
+        books: List<BookItem>,
+        sourceFolders: Set<String>
+    ): DesktopFolderMetadataExtractionResult {
+        if (sourceFolders.isEmpty()) {
+            return DesktopFolderMetadataExtractionResult(books)
+        }
+        return enrichBooks(books) { book -> book.sourceFolder in sourceFolders }
+    }
+
     fun enrichImportedBooks(
         books: List<BookItem>,
         importedBookIds: Set<String>
@@ -465,7 +475,7 @@ object DesktopFolderMetadataExtractor {
         return when (type) {
             FileType.PDF -> Color(156, 65, 70)
             FileType.EPUB -> Color(0, 108, 76)
-            FileType.CBZ, FileType.CBR, FileType.CB7 -> Color(112, 93, 73)
+            FileType.CBZ, FileType.CBR, FileType.CB7, FileType.CBT -> Color(112, 93, 73)
             FileType.MD -> Color(83, 101, 120)
             FileType.HTML -> Color(122, 87, 42)
             FileType.TXT -> Color(74, 92, 112)

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopFolderSyncFeedback.kt

@@ -0,0 +1,16 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.SharedReaderScreenState
+
+internal fun desktopFolderSyncCompletedState(
+    state: SharedReaderScreenState,
+    message: String,
+    failedFolderCount: Int,
+    showBanner: Boolean
+): SharedReaderScreenState {
+    return if (showBanner) {
+        state.withBanner(message, isError = failedFolderCount > 0)
+    } else {
+        state
+    }
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopGeminiCloudTtsAdapter.kt

@@ -33,6 +33,7 @@ import java.net.URI
 import java.net.URLEncoder
 import java.net.http.HttpClient
 import java.net.http.WebSocket
+import java.net.http.WebSocketHandshakeException
 import java.nio.ByteBuffer
 import java.util.Base64
 import java.util.concurrent.CompletableFuture
@@ -56,7 +57,7 @@ class DesktopGeminiCloudTtsAdapter(
     private val networkAccess: () -> Boolean = { true },
     private val workerUrlProvider: () -> String = { "" },
     private val authTokenProvider: suspend () -> String? = { null },
-    private val useWorkerProvider: () -> Boolean = { false },
+    private val useWorkerProvider: () -> Boolean = { true },
     private val onWorkerUsageCompleted: suspend () -> Unit = {},
     httpClient: HttpClient? = null,
     private val cacheManager: ReaderTtsFileCacheManager = ReaderTtsFileCacheManager(defaultDesktopTtsCacheRoot())
@@ -75,14 +76,15 @@ class DesktopGeminiCloudTtsAdapter(
     @Volatile
     private var activePlayer: DesktopStreamingPcmPlayer? = null
 
+    val isPlaybackActive: Boolean
+        get() = activePlayer != null || activeWebSocket != null || activeLine != null
+
     override val isAvailable: Boolean
         get() {
             val settings = settingsProvider().sanitized()
-            return networkAccess() && if (useWorkerProvider()) {
-                settings.serverBackedCloudTts && workerUrlProvider().isNotBlank()
-            } else {
-                settings.isByokCloudTtsAvailable
-            }
+            return networkAccess() &&
+                (settings.isByokCloudTtsAvailable ||
+                    (useWorkerProvider() && settings.serverBackedCloudTts && workerUrlProvider().isNotBlank()))
         }
 
     override suspend fun speak(text: String) {
@@ -125,6 +127,12 @@ class DesktopGeminiCloudTtsAdapter(
                 )
             }
             .filter { it.text.isNotBlank() }
+        logDesktopTtsStartTrace {
+            "event=adapter_speak_chunks book=\"${bookTitle.desktopTtsPreview()}\" scope=${readScope.name} " +
+                "inputChunks=${chunks.size} sequenceChunks=${sequenceChunks.size} " +
+                "inputFirst=${chunks.firstOrNull().desktopTtsStartTraceSummary(160)} " +
+                "sequenceFirstText=\"${sequenceChunks.firstOrNull()?.text.orEmpty().desktopTtsPreview(180)}\""
+        }
         logDesktopTts(
             "chunk_sequence_speak_start book=\"${bookTitle.desktopTtsPreview()}\" scope=${readScope.name} " +
                 "chunks=${sequenceChunks.size} totalTextChars=${sequenceChunks.sumOf { it.text.length }}"
@@ -182,28 +190,27 @@ class DesktopGeminiCloudTtsAdapter(
         onChunkStart: suspend (Int) -> Unit
     ) = withContext(Dispatchers.IO) {
         val settings = settingsProvider().sanitized()
-        val useWorker = useWorkerProvider()
-        val authToken = if (useWorker) authTokenProvider() else null
+        val useWorker = useWorkerProvider() && !settings.isByokCloudTtsAvailable
         val totalTextChars = chunks.sumOf { it.text.length }
         logDesktopTts(
             "stream_start book=\"${bookTitle.desktopTtsPreview()}\" chunks=${chunks.size} totalTextChars=$totalTextChars keyPresent=${settings.geminiKey.isNotBlank()} " +
                 "ttsModel=\"${settings.ttsModel.desktopTtsPreview()}\" speaker=\"${settings.ttsSpeakerId.desktopTtsPreview()}\" " +
-                "available=${settings.isCloudTtsAvailable} worker=$useWorker"
+                "available=${settings.isCloudTtsAvailable} serverBacked=${settings.serverBackedCloudTts} worker=$useWorker"
         )
         if (!networkAccess()) {
             logDesktopTts("stream_blocked reason=network_disabled")
             throw IllegalStateException("Cloud TTS is unavailable in this desktop build.")
         }
-        if (!settings.isCloudTtsAvailable) {
-            logDesktopTts("stream_blocked reason=not_available")
-            throw IllegalStateException(
-                if (useWorker) {
-                    "Cloud TTS needs a signed-in account with credits."
-                } else {
-                    "Cloud TTS needs a saved Gemini key and the Gemini cloud TTS model selected."
-                }
-            )
+        if (useWorker) {
+            if (!settings.serverBackedCloudTts || workerUrlProvider().isBlank()) {
+                logDesktopTts("stream_blocked reason=server_backed_not_available")
+                throw IllegalStateException("Cloud TTS needs a signed-in account with credits.")
+            }
+        } else if (!settings.isByokCloudTtsAvailable) {
+            logDesktopTts("stream_blocked reason=byok_not_available")
+            throw IllegalStateException("Cloud TTS needs a saved Gemini key and the Gemini cloud TTS model selected.")
         }
+        val authToken = if (useWorker) authTokenProvider() else null
         if (useWorker && authToken.isNullOrBlank()) {
             logDesktopTts("stream_blocked reason=missing_auth_token")
             throw IllegalStateException("Sign in with Google to use cloud TTS.")
@@ -220,6 +227,7 @@ class DesktopGeminiCloudTtsAdapter(
         val messageBuffer = StringBuilder()
         var webSocket: WebSocket? = null
         var activeTempCacheFile: File? = null
+        var workerGeneratedAudio = false
 
         fun handleMessage(message: String) {
             handleGeminiTtsMessage(
@@ -329,7 +337,7 @@ class DesktopGeminiCloudTtsAdapter(
                     .get(15, TimeUnit.SECONDS)
             }.getOrElse { error ->
                 logDesktopTts("ws_connect_failed error=\"${error.desktopTtsSummary()}\"")
-                throw error
+                throw IllegalStateException(desktopTtsConnectionMessage(error), error)
             }
             activeWebSocket = connectedWebSocket
             webSocket = connectedWebSocket
@@ -361,6 +369,10 @@ class DesktopGeminiCloudTtsAdapter(
                 currentTurnAudioBytesReceived.set(0)
                 currentTurnComplete.set(turnComplete)
                 logDesktopTts("sequence_turn_start index=${index + 1}/${chunks.size} textChars=${text.length}")
+                logDesktopTtsStartTrace {
+                    "event=adapter_turn_start index=${index + 1}/${chunks.size} chapter=\"${chunk.chapterTitle.orEmpty().desktopTtsPreview()}\" " +
+                        "textChars=${text.length} text=\"${text.desktopTtsPreview(220)}\""
+                }
                 withContext(callbackContext) {
                     onChunkStart(index)
                 }
@@ -420,6 +432,10 @@ class DesktopGeminiCloudTtsAdapter(
                         logDesktopTts("stream_failed reason=empty_turn_audio index=${index + 1}/${chunks.size}")
                         throw IllegalStateException("Cloud TTS returned no audio for a text chunk.")
                     }
+                    if (useWorker) {
+                        workerGeneratedAudio = true
+                        onWorkerUsageCompleted()
+                    }
                     activeCacheOutput.getAndSet(null)?.close()
                     runCatching {
                         patchReaderTtsWavHeader(tempCacheFile, turnAudioBytes.toInt())
@@ -454,8 +470,15 @@ class DesktopGeminiCloudTtsAdapter(
             activeWebSocket = null
             activePlayer = null
             logDesktopTts("stream_complete chunks=${chunks.size} audioBytes=${audioBytesReceived.get()}")
-            if (useWorker) onWorkerUsageCompleted()
+            if (useWorker && workerGeneratedAudio) onWorkerUsageCompleted()
         } catch (error: Throwable) {
+            if (useWorker && desktopTtsShouldRefreshAccountAfterError(error)) {
+                try {
+                    onWorkerUsageCompleted()
+                } catch (_: Throwable) {
+                    // Keep the original TTS failure as the visible error.
+                }
+            }
             currentTurnComplete.set(null)
             activeCacheOutput.getAndSet(null)?.let { output -> runCatching { output.close() } }
             activeTempCacheFile?.delete()
@@ -629,6 +652,39 @@ private fun ByteArray.upsample16BitMonoLe2x(): ByteArray {
     return output
 }
 
+private fun desktopTtsConnectionMessage(error: Throwable): String {
+    val causes = generateSequence(error) { it.cause }.toList()
+    val handshake = causes.filterIsInstance<WebSocketHandshakeException>().firstOrNull()
+    return when (handshake?.response?.statusCode()) {
+        401 -> "Sign in again to use cloud TTS."
+        402 -> "Out of credits. Pro and credits can only be purchased from the Android app."
+        403 -> "Cloud TTS is unavailable for this account."
+        405 -> "Cloud TTS is not configured for this desktop build."
+        426 -> "Cloud TTS is not configured for this desktop build."
+        502 -> "Cloud TTS service is temporarily unavailable."
+        else -> {
+            val details = causes
+                .joinToString(" ") { it.message.orEmpty() }
+                .trim()
+            when {
+                details.contains("INSUFFICIENT_CREDITS", ignoreCase = true) ->
+                    "Out of credits. Pro and credits can only be purchased from the Android app."
+                details.contains("401") || details.contains("Unauthorized", ignoreCase = true) ->
+                    "Sign in again to use cloud TTS."
+                else -> "Cloud TTS failed to connect."
+            }
+        }
+    }
+}
+
+private fun desktopTtsShouldRefreshAccountAfterError(error: Throwable): Boolean {
+    val details = generateSequence(error) { it.cause }
+        .joinToString(" ") { it.message.orEmpty() }
+    return details.contains("Out of credits", ignoreCase = true) ||
+        details.contains("INSUFFICIENT_CREDITS", ignoreCase = true) ||
+        details.contains("402", ignoreCase = true)
+}
+
 private class DesktopStreamingPcmPlayer(
     private val onLineChanged: (SourceDataLine?) -> Unit
 ) {
@@ -742,7 +798,6 @@ private class DesktopStreamingPcmPlayer(
                 openLine(24_000f)
             }.onFailure { secondError ->
                 logDesktopTts("play_fallback_failed sampleRate=24000 error=\"${secondError.desktopTtsSummary()}\"")
-                secondError.printStackTrace()
             }.getOrElse {
                 throw firstError
             }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopLibraryDatabase.kt

@@ -3,18 +3,38 @@ package com.aryan.reader.desktop
 import com.aryan.reader.shared.SharedLibrarySnapshot
 import com.aryan.reader.shared.SharedLibrarySnapshotJson
 import java.io.File
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.jsonObject
 
 class DesktopLibraryDatabase(
     private val databaseFile: File = defaultDatabaseFile()
 ) {
     fun load(): SharedLibrarySnapshot {
-        if (!databaseFile.exists()) return SharedLibrarySnapshot()
-        return SharedLibrarySnapshotJson.decodeOrEmpty(databaseFile.readText())
+        return loadFile(databaseFile)
+            ?: loadFile(backupFile())
+            ?: SharedLibrarySnapshot()
     }
 
     fun save(snapshot: SharedLibrarySnapshot) {
-        databaseFile.parentFile?.mkdirs()
-        databaseFile.writeText(SharedLibrarySnapshotJson.encode(snapshot))
+        val encoded = SharedLibrarySnapshotJson.encode(snapshot)
+        databaseFile.writeTextAtomically(encoded)
+        runCatching {
+            backupFile().writeTextAtomically(encoded)
+        }
+    }
+
+    private fun loadFile(file: File): SharedLibrarySnapshot? {
+        if (!file.isFile) return null
+        val raw = runCatching { file.readText() }.getOrNull() ?: return null
+        val isJsonObject = runCatching {
+            libraryDatabaseJson.parseToJsonElement(raw).jsonObject
+        }.isSuccess
+        if (!isJsonObject) return null
+        return SharedLibrarySnapshotJson.decodeOrEmpty(raw)
+    }
+
+    private fun backupFile(): File {
+        return File(databaseFile.parentFile ?: File("."), "${databaseFile.name}.bak")
     }
 
     companion object {
@@ -23,3 +43,5 @@ class DesktopLibraryDatabase(
         }
     }
 }
+
+private val libraryDatabaseJson = Json { ignoreUnknownKeys = true }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopLibraryUi.kt

@@ -1,5 +1,6 @@
 package com.aryan.reader.desktop
 
+import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
@@ -19,12 +20,14 @@ import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
@@ -44,7 +47,6 @@ import com.aryan.reader.shared.reader.ReaderSettings
 import com.aryan.reader.shared.reduce
 import com.aryan.reader.shared.ui.NonReaderLibraryTab
 import com.aryan.reader.shared.ui.SharedLibraryScreen
-import com.aryan.reader.shared.ui.SharedShelvesScreen
 import com.aryan.reader.shared.ui.SharedStableOutlinedTextField
 import com.aryan.reader.shared.ui.readerString
 import java.io.File
@@ -117,82 +119,62 @@ internal fun resolvedDesktopReaderSettings(
 
 @Composable
 internal fun DesktopReaderOpeningScreen(
-    opening: DesktopReaderOpening
+    opening: DesktopReaderOpening,
+    readerSettings: ReaderSettings? = null
 ) {
+    LaunchedEffect(opening.requestId) {
+        logDesktopReaderOpenTrace {
+            opening.openTracePrefix("desktop_opening_screen_composed")
+        }
+    }
+    val background = readerSettings?.desktopOpeningBackgroundColor() ?: MaterialTheme.colorScheme.background
+    val foreground = readerSettings?.desktopOpeningForegroundColor() ?: MaterialTheme.colorScheme.onBackground
     Box(
-        modifier = Modifier.fillMaxSize().padding(32.dp),
+        modifier = Modifier
+            .fillMaxSize()
+            .background(background)
+            .padding(32.dp),
         contentAlignment = Alignment.Center
     ) {
         Column(
             horizontalAlignment = Alignment.CenterHorizontally,
             verticalArrangement = Arrangement.spacedBy(12.dp)
         ) {
-            CircularProgressIndicator()
+            CircularProgressIndicator(color = foreground)
             Text(
                 text = readerString("desktop_opening_title", "Opening %1\$s", opening.title),
                 style = MaterialTheme.typography.titleMedium,
                 fontWeight = FontWeight.SemiBold,
+                color = foreground,
                 textAlign = TextAlign.Center
             )
             Text(
                 text = opening.formatLabel,
                 style = MaterialTheme.typography.bodyMedium,
-                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                color = foreground.copy(alpha = 0.72f),
                 textAlign = TextAlign.Center
             )
         }
     }
 }
 
-@Composable
-internal fun HomeScreen(
-    state: SharedReaderScreenState,
-    selectedLibraryTab: NonReaderLibraryTab,
-    onLibraryTabChange: (NonReaderLibraryTab) -> Unit,
-    onStateChange: (SharedReaderScreenState) -> Unit,
-    onImportBooks: () -> Unit,
-    onImportFolder: () -> Unit,
-    onRead: (BookItem) -> Unit,
-    onSelect: (String) -> Unit,
-    onClearSelection: () -> Unit,
-    onRemoveSelected: () -> Unit,
-    onShowBookInfo: (BookItem) -> Unit,
-    onEditBook: (BookItem) -> Unit,
-    onCreateShelf: () -> Unit,
-    onCreateSmartShelf: () -> Unit,
-    onRenameShelf: (Shelf) -> Unit,
-    onDeleteShelf: (Shelf) -> Unit,
-    onRemoveFolder: (Shelf) -> Unit,
-    onTagSelectedBooks: () -> Unit,
-    onAddSelectedBooksToShelf: () -> Unit,
-    onSyncFolderMetadata: () -> Unit,
-    onScanFolders: () -> Unit,
-    onTogglePinned: (BookItem) -> Unit
-) {
-    LibraryScreen(
-        state = state,
-        selectedLibraryTab = selectedLibraryTab,
-        onLibraryTabChange = onLibraryTabChange,
-        onStateChange = onStateChange,
-        onImportBooks = onImportBooks,
-        onImportFolder = onImportFolder,
-        onRead = onRead,
-        onSelect = onSelect,
-        onClearSelection = onClearSelection,
-        onRemoveSelected = onRemoveSelected,
-        onShowBookInfo = onShowBookInfo,
-        onEditBook = onEditBook,
-        onCreateShelf = onCreateShelf,
-        onCreateSmartShelf = onCreateSmartShelf,
-        onRenameShelf = onRenameShelf,
-        onDeleteShelf = onDeleteShelf,
-        onRemoveFolder = onRemoveFolder,
-        onTagSelectedBooks = onTagSelectedBooks,
-        onAddSelectedBooksToShelf = onAddSelectedBooksToShelf,
-        onSyncFolderMetadata = onSyncFolderMetadata,
-        onScanFolders = onScanFolders,
-        onTogglePinned = onTogglePinned
-    )
+private fun ReaderSettings.desktopOpeningBackgroundColor(): Color {
+    return backgroundColorArgb?.toDesktopOpeningComposeColor()
+        ?: if (darkMode) Color(0xFF171A17) else Color(0xFFFFFCF5)
+}
+
+private fun ReaderSettings.desktopOpeningForegroundColor(): Color {
+    return textColorArgb?.toDesktopOpeningComposeColor()
+        ?: if (darkMode) Color(0xFFE7E3D8) else Color(0xFF24231F)
+}
+
+private fun Long.toDesktopOpeningComposeColor(): Color {
+    val value = this and 0xFFFFFFFFL
+    val alpha = ((value shr 24) and 0xFF) / 255f
+    val red = ((value shr 16) and 0xFF) / 255f
+    val green = ((value shr 8) and 0xFF) / 255f
+    val blue = (value and 0xFF) / 255f
+    return Color(red = red, green = green, blue = blue, alpha = alpha.takeIf { it > 0f } ?: 1f)
 }
 
 @Composable
@@ -209,12 +191,15 @@ internal fun LibraryScreen(
     onShowBookInfo: (BookItem) -> Unit,
     onEditBook: (BookItem) -> Unit,
     onCreateShelf: () -> Unit,
+    onCreateShelfWithBooks: (String, Set<String>) -> Unit,
     onCreateSmartShelf: () -> Unit,
     onRenameShelf: (Shelf) -> Unit,
     onDeleteShelf: (Shelf) -> Unit,
     onRemoveFolder: (Shelf) -> Unit,
     onTagSelectedBooks: () -> Unit,
     onAddSelectedBooksToShelf: () -> Unit,
+    onAddBooksToShelf: (Set<String>) -> Unit,
+    onManageShelfBooks: (Shelf) -> Unit,
     onImportFolder: () -> Unit,
     onSyncFolderMetadata: () -> Unit,
     onScanFolders: () -> Unit,
@@ -233,12 +218,15 @@ internal fun LibraryScreen(
         onShowBookInfo = onShowBookInfo,
         onEditBook = onEditBook,
         onCreateShelf = onCreateShelf,
+        onCreateShelfWithBooks = onCreateShelfWithBooks,
         onCreateSmartShelf = onCreateSmartShelf,
         onRenameShelf = onRenameShelf,
         onDeleteShelf = onDeleteShelf,
         onRemoveFolder = onRemoveFolder,
         onTagSelectedBooks = onTagSelectedBooks,
         onAddSelectedBooksToShelf = onAddSelectedBooksToShelf,
+        onAddBooksToShelf = onAddBooksToShelf,
+        onManageShelfBooks = onManageShelfBooks,
         onImportFolder = onImportFolder,
         onSyncFolderMetadata = onSyncFolderMetadata,
         onScanFolders = onScanFolders,
@@ -248,39 +236,6 @@ internal fun LibraryScreen(
     )
 }
 
-@Composable
-internal fun ShelvesScreen(
-    shelves: List<Shelf>,
-    selectedBookIds: Set<String>,
-    pinnedBookIds: Set<String>,
-    onRead: (BookItem) -> Unit,
-    onSelect: (String) -> Unit,
-    onShowBookInfo: (BookItem) -> Unit,
-    onEditBook: (BookItem) -> Unit,
-    onTogglePinned: (BookItem) -> Unit,
-    onCreateShelf: () -> Unit,
-    onCreateSmartShelf: () -> Unit,
-    onRenameShelf: (Shelf) -> Unit,
-    onDeleteShelf: (Shelf) -> Unit,
-    onRemoveFolder: (Shelf) -> Unit
-) {
-    SharedShelvesScreen(
-        shelves = shelves,
-        selectedBookIds = selectedBookIds,
-        pinnedBookIds = pinnedBookIds,
-        onOpenBook = onRead,
-        onToggleSelection = onSelect,
-        onShowBookInfo = onShowBookInfo,
-        onEditBook = onEditBook,
-        onTogglePinned = onTogglePinned,
-        onCreateShelf = onCreateShelf,
-        onCreateSmartShelf = onCreateSmartShelf,
-        onRenameShelf = onRenameShelf,
-        onDeleteShelf = onDeleteShelf,
-        onRemoveFolder = onRemoveFolder
-    )
-}
-
 private data class DesktopSmartRuleDraft(
     val field: SmartField = SmartField.TITLE,
     val operator: SmartOperator = SmartOperator.CONTAINS,

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopLocalFolderSync.kt

@@ -24,6 +24,7 @@ import com.aryan.reader.shared.pdf.SharedPdfAnnotationSidecarCodec
 import com.aryan.reader.shared.pdf.SharedPdfRichTextLog
 import com.aryan.reader.shared.pdf.SharedPdfRichTextSerializer
 import com.aryan.reader.shared.toSharedFolderBookMetadata
+import com.aryan.reader.shared.toStablePositionCfi
 import kotlinx.serialization.encodeToString
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.JsonElement
@@ -46,7 +47,8 @@ data class DesktopLocalFolderSyncResult(
     val metadataStats: DesktopFolderMetadataExtractionStats = DesktopFolderMetadataExtractionStats(),
     val idMigrations: Map<String, String> = emptyMap(),
     val removedBookIds: Set<String> = emptySet(),
-    val failedFolders: List<String> = emptyList()
+    val failedFolders: List<String> = emptyList(),
+    val processedFolderUris: List<String> = emptyList()
 )
 
 object DesktopLocalFolderSync {
@@ -56,10 +58,18 @@ object DesktopLocalFolderSync {
         if (!folder.isDirectory) return false
         return folder.walkTopDown()
             .onEnter { it == folder || it.shouldEnterSyncedFolder() }
+            .onFail { file, error ->
+                logDesktopFolderSync(
+                    "folder.supportedFiles.skipInaccessible path=\"${file.absolutePath.folderSyncPreview()}\" " +
+                        "error=${error.folderSyncSummary()}"
+                )
+            }
             .any { file ->
-                file.isFile &&
-                    file.shouldSyncBookFile() &&
-                    SharedFileCapabilities.fileTypeForName(file.name) in desktopSyncableTypes
+                runCatching {
+                    file.isFile &&
+                        file.shouldSyncBookFile() &&
+                        SharedFileCapabilities.fileTypeForName(file.name) in desktopSyncableTypes
+                }.getOrDefault(false)
             }
     }
 
@@ -68,9 +78,11 @@ object DesktopLocalFolderSync {
         shelfRefs: List<BookShelfRef>,
         targetFolder: File? = null,
         nowMillis: Long = System.currentTimeMillis(),
-        metadataOnly: Boolean = false
+        metadataOnly: Boolean = false,
+        extractMetadata: Boolean = true
     ): DesktopLocalFolderSyncResult {
         val requestedFolders = foldersToSync(state, targetFolder, nowMillis)
+            .filter { it.localSyncEnabled }
         val mode = if (metadataOnly) "metadata" else "full"
         logDesktopFolderSync(
             "sync.start mode=$mode target=\"${targetFolder?.absolutePath?.folderSyncPreview() ?: "ALL"}\" " +
@@ -84,6 +96,7 @@ object DesktopLocalFolderSync {
         val allMigrations = linkedMapOf<String, String>()
         val allRemovedBookIds = linkedSetOf<String>()
         val failedFolders = mutableListOf<String>()
+        val processedFolderUris = mutableListOf<String>()
 
         requestedFolders.forEach { folder ->
             val root = File(folder.uriString)
@@ -95,6 +108,7 @@ object DesktopLocalFolderSync {
                 failedFolders += folder.name
                 return@forEach
             }
+            processedFolderUris += folder.uriString
 
             logDesktopFolderSync(
                 "folder.start mode=$mode name=\"${folder.name.folderSyncPreview()}\" " +
@@ -138,8 +152,27 @@ object DesktopLocalFolderSync {
             logDesktopFolderSync(
                 "folder.sidecars.importCheck mode=$mode name=\"${folder.name.folderSyncPreview()}\" books=${syncedBooks.size}"
             )
-            importAnnotationSidecars(root, syncedBooks)
-            if (!metadataOnly) {
+            runCatching {
+                importAnnotationSidecars(root, syncedBooks)
+            }.onFailure { error ->
+                logDesktopFolderSync(
+                    "annotation.import.failed mode=$mode name=\"${folder.name.folderSyncPreview()}\" " +
+                        "root=\"${root.absolutePath.folderSyncPreview()}\" error=${error.folderSyncSummary()}"
+                )
+            }
+            syncedBooks.forEach { book ->
+                remoteMetadata[book.id]?.let { metadata ->
+                    runCatching {
+                        importDesktopPdfBookmarksMetadata(book, metadata.bookmarksJson, metadata.lastModifiedTimestamp)
+                    }.onFailure { error ->
+                        logDesktopFolderSync(
+                            "metadata.bookmarks.importFailed book=${book.id} " +
+                                "error=${error.folderSyncSummary()}"
+                        )
+                    }
+                }
+            }
+            if (!metadataOnly && extractMetadata) {
                 val metadataResult = DesktopFolderMetadataExtractor.enrichFolderBooks(
                     books = nextState.rawLibraryBooks,
                     sourceFolder = folder.uriString
@@ -173,7 +206,8 @@ object DesktopLocalFolderSync {
             metadataStats = totalMetadataStats,
             idMigrations = allMigrations,
             removedBookIds = allRemovedBookIds,
-            failedFolders = failedFolders
+            failedFolders = failedFolders,
+            processedFolderUris = processedFolderUris
         )
         logDesktopFolderSync(
             "sync.done mode=$mode failed=${failedFolders.size} new=${totalStats.newBooks} " +
@@ -188,8 +222,13 @@ object DesktopLocalFolderSync {
         savePdfAnnotationSidecar(book)
     }
 
+    fun deleteSyncDataFolder(root: File): Boolean {
+        val syncDir = File(root, LOCAL_FOLDER_SYNC_DATA_DIR)
+        return !syncDir.exists() || syncDir.isDirectory && syncDir.deleteRecursively()
+    }
+
     fun saveBookMetadata(book: BookItem) {
-        val metadata = book.toSharedFolderBookMetadata()
+        val metadata = book.toDesktopFolderBookMetadata()
         if (metadata == null) {
             logDesktopFolderSync(
                 "metadata.export.skipClean book=${book.id} title=\"${book.title.orEmpty().folderSyncPreview()}\" " +
@@ -242,11 +281,9 @@ object DesktopLocalFolderSync {
         val data = buildMap {
             if (annotationFile.isFile) {
                 val annotationJson = annotationFile.readText().trim()
-                val annotations = SharedPdfAnnotationSerializer.decode(annotationJson)
-                put(
-                    SharedPdfAnnotationSidecarCodec.KEY_PDF_ANNOTATIONS,
-                    SharedPdfAnnotationSidecarCodec.encodeAnnotationsElement(annotations)
-                )
+                desktopPdfAnnotationElementForSync(annotationJson)?.let { annotations ->
+                    put(SharedPdfAnnotationSidecarCodec.KEY_PDF_ANNOTATIONS, annotations)
+                }
             }
             if (bookmarkFile.isFile) {
                 val bookmarksJson = bookmarkFile.readText().trim()
@@ -267,7 +304,7 @@ object DesktopLocalFolderSync {
                             "file=\"${richTextFile.absolutePath.richSyncPreview()}\" rawLen=${richTextJson.length} " +
                             "textLen=${richTextDocument.text.length} spans=${richTextDocument.spans.size}"
                     )
-                    put("text", SharedPdfRichTextSerializer.encodeElement(richTextDocument))
+                    desktopPdfRichTextElementForSync(richTextJson)?.let { put("text", it) }
                 }
             }
         }
@@ -279,9 +316,9 @@ object DesktopLocalFolderSync {
             return
         }
         val timestamp = maxOf(
-            annotationFile.lastModifiedIfFile(),
+            annotationFile.lastModifiedIfSyncableAnnotations(),
             bookmarkFile.lastModifiedIfFile(),
-            richTextFile.lastModifiedIfFile(),
+            richTextFile.lastModifiedIfSyncableRichText(),
             System.currentTimeMillis()
         )
         val dataJson = desktopFolderSyncJson.encodeToString(
@@ -329,7 +366,15 @@ object DesktopLocalFolderSync {
         val rootPath = root.toPath().toAbsolutePath().normalize()
         return root.walkTopDown()
             .onEnter { it == root || it.shouldEnterSyncedFolder() }
-            .filter { it.isFile && it.shouldSyncBookFile() }
+            .onFail { file, error ->
+                logDesktopFolderSync(
+                    "folder.scan.skipInaccessible root=\"${root.absolutePath.folderSyncPreview()}\" " +
+                        "path=\"${file.absolutePath.folderSyncPreview()}\" error=${error.folderSyncSummary()}"
+                )
+            }
+            .filter { file ->
+                runCatching { file.isFile && file.shouldSyncBookFile() }.getOrDefault(false)
+            }
             .mapNotNull { file ->
                 val type = SharedFileCapabilities.fileTypeForName(file.name)
                     .takeIf { it in desktopSyncableTypes }
@@ -344,8 +389,8 @@ object DesktopLocalFolderSync {
                     sourceFolder = sourceFolder,
                     relativePath = relativePath,
                     type = type,
-                    size = file.length(),
-                    lastModified = file.lastModified()
+                    size = runCatching { file.length() }.getOrDefault(0L),
+                    lastModified = runCatching { file.lastModified() }.getOrDefault(0L)
                 )
             }
             .toList()
@@ -559,13 +604,18 @@ object DesktopLocalFolderSync {
             }
             if (sidecar.data.hasPdfAnnotationPayload()) {
                 val annotations = SharedPdfAnnotationSidecarCodec.annotationsFromData(sidecar.data)
-                annotationFile.parentFile?.mkdirs()
-                annotationFile.writeText(SharedPdfAnnotationSerializer.encode(annotations))
-                annotationFile.setLastModified(sidecar.timestamp)
-                logDesktopFolderSync(
-                    "annotation.import.writeAnnotations book=${book.id} count=${annotations.size} " +
-                        "file=\"${annotationFile.absolutePath.folderSyncPreview()}\""
-                )
+                if (annotations.isEmpty()) {
+                    if (annotationFile.isFile) annotationFile.delete()
+                    logDesktopFolderSync("annotation.import.deleteEmptyAnnotations book=${book.id}")
+                } else {
+                    annotationFile.parentFile?.mkdirs()
+                    annotationFile.writeText(SharedPdfAnnotationSerializer.encode(annotations))
+                    annotationFile.setLastModified(sidecar.timestamp)
+                    logDesktopFolderSync(
+                        "annotation.import.writeAnnotations book=${book.id} count=${annotations.size} " +
+                            "file=\"${annotationFile.absolutePath.folderSyncPreview()}\""
+                    )
+                }
             }
             sidecar.data["bookmarks"]?.let { bookmarks ->
                 bookmarkFile.parentFile?.mkdirs()
@@ -582,13 +632,18 @@ object DesktopLocalFolderSync {
                         "textLen=${richDocument.text.length} spans=${richDocument.spans.size} " +
                         "file=\"${richTextFile.absolutePath.richSyncPreview()}\""
                 )
-                richTextFile.parentFile?.mkdirs()
-                richTextFile.writeText(SharedPdfRichTextSerializer.encode(richDocument))
-                richTextFile.setLastModified(sidecar.timestamp)
-                logDesktopFolderSync(
-                    "annotation.import.writeText book=${book.id} textLen=${richDocument.text.length} " +
-                        "spans=${richDocument.spans.size} file=\"${richTextFile.absolutePath.folderSyncPreview()}\""
-                )
+                if (richDocument.text.isEmpty() && richDocument.spans.isEmpty()) {
+                    if (richTextFile.isFile) richTextFile.delete()
+                    logDesktopFolderSync("annotation.import.deleteEmptyText book=${book.id}")
+                } else {
+                    richTextFile.parentFile?.mkdirs()
+                    richTextFile.writeText(SharedPdfRichTextSerializer.encode(richDocument))
+                    richTextFile.setLastModified(sidecar.timestamp)
+                    logDesktopFolderSync(
+                        "annotation.import.writeText book=${book.id} textLen=${richDocument.text.length} " +
+                            "spans=${richDocument.spans.size} file=\"${richTextFile.absolutePath.folderSyncPreview()}\""
+                    )
+                }
             }
         }
     }
@@ -814,6 +869,56 @@ private fun File.lastModifiedIfFile(): Long {
     return if (isFile) lastModified() else 0L
 }
 
+private fun File.hasSyncablePdfAnnotations(): Boolean {
+    return isFile && desktopPdfAnnotationElementForSync(readText()) != null
+}
+
+private fun File.lastModifiedIfSyncableAnnotations(): Long {
+    return if (hasSyncablePdfAnnotations()) lastModified() else 0L
+}
+
+private fun File.hasSyncablePdfRichText(): Boolean {
+    return isFile && desktopPdfRichTextElementForSync(readText()) != null
+}
+
+private fun File.lastModifiedIfSyncableRichText(): Long {
+    return if (hasSyncablePdfRichText()) lastModified() else 0L
+}
+
+private fun BookItem.toDesktopFolderBookMetadata(): SharedFolderBookMetadata? {
+    val base = toSharedFolderBookMetadata()
+    val pdfBookmarksJson = desktopPdfBookmarksMetadataJson(this)
+    if (base == null && pdfBookmarksJson == null) return null
+
+    val timestamp = maxOf(
+        base?.lastModifiedTimestamp ?: 0L,
+        desktopPdfBookmarkMetadataTimestamp(this),
+        this.timestamp
+    )
+
+    return (base ?: SharedFolderBookMetadata(
+        bookId = id,
+        title = null,
+        author = null,
+        displayName = displayName,
+        type = type.name,
+        lastChapterIndex = readerPosition?.chapterIndex,
+        lastPage = readerPosition?.pageIndex ?: lastPageIndex,
+        lastPositionCfi = readerPosition?.toStablePositionCfi(),
+        progressPercentage = progressPercentage ?: 0f,
+        isRecent = isRecent,
+        lastModifiedTimestamp = timestamp,
+        bookmarksJson = null,
+        locatorBlockIndex = readerPosition?.blockIndex,
+        locatorCharOffset = readerPosition?.charOffset,
+        customName = null,
+        highlightsJson = null
+    )).copy(
+        lastModifiedTimestamp = timestamp,
+        bookmarksJson = pdfBookmarksJson ?: base?.bookmarksJson
+    )
+}
+
 private fun uniqueFolderSyncTempName(baseName: String): String {
     val stem = baseName.removeSuffix(".tmp")
     val nonce = "${System.currentTimeMillis()}_${Thread.currentThread().id}_${System.nanoTime().toString(36)}"

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPaidAiAdapter.kt

@@ -16,6 +16,7 @@ import kotlinx.serialization.json.jsonPrimitive
 import java.io.InputStream
 import java.net.HttpURLConnection
 import java.net.URL
+import kotlin.math.ceil
 
 internal class DesktopPaidAiAdapter(
     private val config: DesktopCloudConfig,
@@ -25,7 +26,7 @@ internal class DesktopPaidAiAdapter(
     private val currentSignedIn: () -> Boolean,
     private val currentIsProUser: () -> Boolean,
     private val currentCredits: () -> Int,
-    private val onUsageCompleted: suspend () -> Unit = {}
+    private val onUsageReported: (DesktopPaidAiUsage) -> Unit = {}
 ) : AiAdapter {
     override val isAvailable: Boolean
         get() = networkAccess() &&
@@ -196,13 +197,18 @@ internal class DesktopPaidAiAdapter(
                 val responseCode = connection.responseCode
                 val stream = if (responseCode in 200..299) connection.inputStream else connection.errorStream
                 if (responseCode in 200..299) {
-                    val parsed = readWorkerStream(stream, onChunk, onUsageReceived)
+                    val parsed = readWorkerStream(
+                        stream = stream,
+                        onChunk = onChunk,
+                        onUsageReceived = onUsageReceived,
+                        onUsageReported = onUsageReported
+                    )
                     if (parsed.text.isBlank()) throw IllegalStateException("The AI service returned an empty response.")
-                    onUsageCompleted()
                     return@runCatching parsed
                 }
                 val responseText = stream?.bufferedReader(Charsets.UTF_8)?.use { it.readText() }.orEmpty()
                 if (connection.responseCode == 402 || responseText.contains("INSUFFICIENT_CREDITS")) {
+                    onUsageReported(DesktopPaidAiUsage())
                     throw IllegalStateException("Out of credits. Pro and credits can only be purchased from the Android app.")
                 }
                 if (connection.responseCode == 401) {
@@ -222,6 +228,19 @@ internal class DesktopPaidAiAdapter(
     }
 }
 
+internal data class DesktopPaidAiUsage(
+    val cost: Double? = null,
+    val freeRemaining: Int? = null
+)
+
+internal fun desktopCreditsAfterPaidAiUsage(currentCredits: Int, cost: Double?): Int {
+    val deducted = cost
+        ?.takeIf { it.isFinite() && it > 0.0 }
+        ?.let { ceil(it).toInt() }
+        ?: return currentCredits
+    return (currentCredits - deducted).coerceAtLeast(0)
+}
+
 private data class DesktopPaidAiResponse(
     val text: String,
     val cost: Double? = null,
@@ -233,18 +252,35 @@ private val DesktopPaidAiJson = Json { ignoreUnknownKeys = true }
 private fun readWorkerStream(
     stream: InputStream?,
     onChunk: (String) -> Unit,
-    onUsageReceived: (cost: Double?, freeRemaining: Int?) -> Unit
+    onUsageReceived: (cost: Double?, freeRemaining: Int?) -> Unit,
+    onUsageReported: (DesktopPaidAiUsage) -> Unit
 ): DesktopPaidAiResponse {
     val output = StringBuilder()
     var cost: Double? = null
     var freeRemaining: Int? = null
+    var paidUsageReported = false
+    var freeUsageReported = false
     stream?.bufferedReader(Charsets.UTF_8)?.useLines { lines ->
         lines.forEach { line ->
-            val parsed = parseWorkerStreamLine(line) ?: return@forEach
+            val parsed = try {
+                parseWorkerStreamLine(line)
+            } catch (error: IllegalStateException) {
+                if (desktopPaidAiShouldRefreshAccountAfterError(error)) {
+                    onUsageReported(DesktopPaidAiUsage())
+                }
+                throw error
+            } ?: return@forEach
             parsed.cost?.let { cost = it }
             parsed.freeRemaining?.let { freeRemaining = it }
             if (parsed.cost != null || parsed.freeRemaining != null) {
                 onUsageReceived(parsed.cost, parsed.freeRemaining)
+                if (parsed.cost != null && !paidUsageReported) {
+                    paidUsageReported = true
+                    onUsageReported(DesktopPaidAiUsage(cost = parsed.cost, freeRemaining = parsed.freeRemaining))
+                } else if (parsed.freeRemaining != null && !freeUsageReported) {
+                    freeUsageReported = true
+                    onUsageReported(DesktopPaidAiUsage(freeRemaining = parsed.freeRemaining))
+                }
             }
             parsed.chunk?.let { chunk ->
                 output.append(chunk)
@@ -275,6 +311,14 @@ private data class DesktopPaidAiStreamLine(
     val freeRemaining: Int? = null
 )
 
+private fun desktopPaidAiShouldRefreshAccountAfterError(error: Throwable): Boolean {
+    val details = generateSequence(error) { it.cause }
+        .joinToString(" ") { it.message.orEmpty() }
+    return details.contains("Out of credits", ignoreCase = true) ||
+        details.contains("INSUFFICIENT_CREDITS", ignoreCase = true) ||
+        details.contains("402", ignoreCase = true)
+}
+
 private fun workerErrorMessage(errorBody: String): String? {
     return when {
         errorBody.contains("INSUFFICIENT_CREDITS") -> "Out of credits. Pro and credits can only be purchased from the Android app."

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfAnnotationUi.kt

@@ -9,14 +9,17 @@ import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.heightIn
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.ContentCopy
 import androidx.compose.material.icons.filled.Search
@@ -40,24 +43,32 @@ import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.luminance
 import androidx.compose.ui.graphics.toArgb
 import androidx.compose.ui.graphics.vector.ImageVector
+import androidx.compose.ui.text.font.FontStyle
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
+import com.aryan.reader.shared.pdf.DEFAULT_SHARED_PDF_COMMENT_AUTHOR
 import com.aryan.reader.shared.pdf.PdfAnnotationKind
 import com.aryan.reader.shared.pdf.PdfInkTool
-import com.aryan.reader.shared.pdf.SharedPdfAndroidHighlightColors
 import com.aryan.reader.shared.pdf.SharedPdfAnnotation
+import com.aryan.reader.shared.pdf.SharedPdfAnnotationComment
 import com.aryan.reader.shared.pdf.SharedPdfAnnotationDefaults
 import com.aryan.reader.shared.pdf.SharedPdfEmbeddedAnnotation
 import com.aryan.reader.shared.pdf.SharedPdfHighlighterPalette
+import com.aryan.reader.shared.pdf.pdfCommentChildren
 import com.aryan.reader.shared.pdf.sharedPdfStrokePercent
 import com.aryan.reader.shared.pdf.sharedPdfStrokeWidthRange
 import com.aryan.reader.shared.pdf.sharedPdfTextStyle
+import com.aryan.reader.shared.pdf.visiblePdfAnnotationComments
+import com.aryan.reader.shared.pdf.withoutPdfCommentThread
 import com.aryan.reader.shared.pdf.withSharedPdfTextStyle
 import com.aryan.reader.shared.ui.SharedHsvColorPickerDialog
 import com.aryan.reader.shared.ui.SharedPdfTextStyleControls
 import com.aryan.reader.shared.ui.SharedStableOutlinedTextField
 import com.aryan.reader.shared.ui.readerString
+import java.text.DateFormat
+import java.util.Date
+import java.util.UUID
 
 internal val DesktopPdfAnnotationTools = listOf(
     PdfInkTool.PEN,
@@ -69,6 +80,11 @@ internal val DesktopPdfAnnotationTools = listOf(
     PdfInkTool.ERASER
 )
 
+private enum class DesktopPdfAnnotationSheetSection {
+    NOTE,
+    COMMENTS
+}
+
 @Composable
 internal fun DesktopPdfAnnotationEditor(
     annotation: SharedPdfAnnotation,
@@ -82,12 +98,51 @@ internal fun DesktopPdfAnnotationEditor(
     onSearch: () -> Unit
 ) {
     val highlighterColors = remember(highlighterPalette) {
-        SharedPdfAndroidHighlightColors.palette
+        SharedPdfHighlighterPalette(highlighterPalette).sanitized().colors
     }
     var editingHighlighterSlot by remember(annotation.id, highlighterColors) { mutableStateOf<Int?>(null) }
+    var editingHighlighterDraftColors by remember(annotation.id, highlighterColors) {
+        mutableStateOf<List<Int>>(emptyList())
+    }
     val isHighlighterAnnotation = annotation.kind == PdfAnnotationKind.HIGHLIGHT ||
         annotation.tool == PdfInkTool.HIGHLIGHTER ||
         annotation.tool == PdfInkTool.HIGHLIGHTER_ROUND
+    var selectedSection by remember(annotation.id) { mutableStateOf(DesktopPdfAnnotationSheetSection.NOTE) }
+    var commentText by remember(annotation.id) { mutableStateOf("") }
+    var replyTargetId by remember(annotation.id) { mutableStateOf<String?>(null) }
+    var editingCommentId by remember(annotation.id) { mutableStateOf<String?>(null) }
+    var commentAuthor by remember(annotation.id) {
+        mutableStateOf(
+            annotation.comments
+                .lastOrNull { it.author.isNotBlank() }
+                ?.author
+                ?: DEFAULT_SHARED_PDF_COMMENT_AUTHOR
+        )
+    }
+
+    fun updateComments(nextComments: List<SharedPdfAnnotationComment>) {
+        onUpdate(annotation.copy(comments = nextComments))
+    }
+
+    fun highlighterDraftColors(): List<Int> {
+        return editingHighlighterDraftColors.ifEmpty { highlighterColors }
+    }
+
+    fun updateHighlighterDraft(slotIndex: Int, color: Color): List<Int> {
+        val nextColors = highlighterDraftColors().toMutableList()
+        if (slotIndex in nextColors.indices) {
+            nextColors[slotIndex] = color.copy(alpha = SharedPdfHighlighterPalette.DefaultAlpha / 255f).toArgb()
+            editingHighlighterDraftColors = nextColors
+        }
+        return nextColors
+    }
+
+    fun openHighlighterEditor(slotIndex: Int) {
+        if (editingHighlighterSlot == null) {
+            editingHighlighterDraftColors = highlighterColors
+        }
+        editingHighlighterSlot = slotIndex
+    }
 
     Surface(
         color = MaterialTheme.colorScheme.surface,
@@ -127,7 +182,7 @@ internal fun DesktopPdfAnnotationEditor(
                         )
                         Text(
                             "\"${annotation.text}\"",
-                            style = MaterialTheme.typography.bodyMedium,
+                            style = MaterialTheme.typography.bodyMedium.copy(fontStyle = FontStyle.Italic),
                             maxLines = 4,
                             overflow = TextOverflow.Ellipsis,
                             color = MaterialTheme.colorScheme.onSurface.copy(alpha = 0.88f),
@@ -185,12 +240,7 @@ internal fun DesktopPdfAnnotationEditor(
                             modifier = Modifier
                                 .size(26.dp)
                                 .clickable {
-                                    val nextColor = if (isHighlighterAnnotation) {
-                                        SharedPdfAndroidHighlightColors.nearestArgb(argb)
-                                    } else {
-                                        argb
-                                    }
-                                    onUpdate(annotation.copy(colorArgb = nextColor))
+                                    onUpdate(annotation.copy(colorArgb = argb))
                                 },
                             color = Color(argb),
                             shape = RoundedCornerShape(13.dp),
@@ -217,24 +267,103 @@ internal fun DesktopPdfAnnotationEditor(
                                 )
                                 .border(1.dp, MaterialTheme.colorScheme.outline.copy(alpha = 0.32f), RoundedCornerShape(15.dp))
                                 .clickable {
-                                    editingHighlighterSlot = highlighterColors
-                                        .indexOf(annotation.colorArgb)
-                                        .takeIf { it >= 0 }
-                                        ?: 0
+                                    openHighlighterEditor(
+                                        highlighterColors
+                                            .indexOf(annotation.colorArgb)
+                                            .takeIf { it >= 0 }
+                                            ?: 0
+                                    )
                                 }
                         )
                     }
                 }
-                SharedStableOutlinedTextField(
-                    value = annotation.note.orEmpty(),
-                    onValueChange = { note -> onUpdate(annotation.copy(note = note.takeIf { it.isNotBlank() })) },
-                    label = { Text(readerString("label_note", "Note")) },
-                    minLines = 3,
-                    maxLines = 5,
-                    modifier = Modifier.fillMaxWidth(),
-                    shape = RoundedCornerShape(12.dp),
-                    selectionKey = annotation.id
+                DesktopPdfAnnotationSheetTabs(
+                    selectedSection = selectedSection,
+                    commentCount = annotation.comments.count { it.contents.isNotBlank() },
+                    onSectionChange = { selectedSection = it }
                 )
+                if (selectedSection == DesktopPdfAnnotationSheetSection.NOTE) {
+                    SharedStableOutlinedTextField(
+                        value = annotation.note.orEmpty(),
+                        onValueChange = { note -> onUpdate(annotation.copy(note = note.takeIf { it.isNotBlank() })) },
+                        label = { Text(readerString("label_note", "Note")) },
+                        minLines = 3,
+                        maxLines = 5,
+                        modifier = Modifier.fillMaxWidth(),
+                        shape = RoundedCornerShape(12.dp),
+                        selectionKey = annotation.id
+                    )
+                } else {
+                    DesktopPdfHighlightCommentsEditor(
+                        comments = annotation.comments,
+                        commentText = commentText,
+                        commentAuthor = commentAuthor,
+                        replyTargetId = replyTargetId,
+                        editingCommentId = editingCommentId,
+                        onCommentTextChange = { commentText = it },
+                        onCommentAuthorChange = { commentAuthor = it },
+                        onReply = { comment ->
+                            editingCommentId = null
+                            replyTargetId = comment.id
+                            commentText = ""
+                        },
+                        onCancelReply = { replyTargetId = null },
+                        onEdit = { comment ->
+                            editingCommentId = comment.id
+                            replyTargetId = null
+                            commentText = comment.contents
+                            commentAuthor = comment.author.ifBlank { DEFAULT_SHARED_PDF_COMMENT_AUTHOR }
+                        },
+                        onCancelEdit = {
+                            editingCommentId = null
+                            commentText = ""
+                        },
+                        onDelete = { comment ->
+                            val nextComments = annotation.comments.withoutPdfCommentThread(comment.id)
+                            updateComments(nextComments)
+                            if (replyTargetId != null && (replyTargetId == comment.id || nextComments.none { it.id == replyTargetId })) {
+                                replyTargetId = null
+                            }
+                            if (editingCommentId != null && (editingCommentId == comment.id || nextComments.none { it.id == editingCommentId })) {
+                                editingCommentId = null
+                                commentText = ""
+                            }
+                        },
+                        onAddComment = {
+                            val contents = commentText.trim()
+                            if (contents.isNotBlank()) {
+                                val now = System.currentTimeMillis()
+                                val author = commentAuthor.trim().ifBlank { DEFAULT_SHARED_PDF_COMMENT_AUTHOR }
+                                val nextComments = if (editingCommentId != null) {
+                                    annotation.comments.map { comment ->
+                                        if (comment.id == editingCommentId) {
+                                            comment.copy(
+                                                author = author,
+                                                contents = contents,
+                                                modifiedAt = now
+                                            )
+                                        } else {
+                                            comment
+                                        }
+                                    }
+                                } else {
+                                    annotation.comments + SharedPdfAnnotationComment(
+                                        id = UUID.randomUUID().toString(),
+                                        parentId = replyTargetId,
+                                        author = author,
+                                        contents = contents,
+                                        createdAt = now,
+                                        modifiedAt = now
+                                    )
+                                }
+                                updateComments(nextComments)
+                                commentText = ""
+                                replyTargetId = null
+                                editingCommentId = null
+                            }
+                        }
+                    )
+                }
             }
             if (annotation.kind == PdfAnnotationKind.INK) {
                 val strokeRange = annotation.tool.sharedPdfStrokeWidthRange()
@@ -261,23 +390,29 @@ internal fun DesktopPdfAnnotationEditor(
         }
     }
     editingHighlighterSlot?.let { requestedSlot ->
-        val slot = requestedSlot.coerceIn(0, highlighterColors.lastIndex)
-        val initialColor = Color(highlighterColors[slot]).copy(alpha = 1f)
+        val draftColors = highlighterDraftColors()
+        val safeDraftColors = draftColors.ifEmpty { SharedPdfHighlighterPalette.defaultColors }
+        val slot = requestedSlot.coerceIn(0, safeDraftColors.lastIndex)
+        val initialColor = remember(slot) { Color(safeDraftColors[slot]).copy(alpha = 1f) }
         SharedHsvColorPickerDialog(
             initialColor = initialColor,
             title = readerString("desktop_highlight_color_format", "Highlight color %1\$d", slot + 1),
             onDismiss = { editingHighlighterSlot = null },
             onSave = { color ->
                 val nextArgb = color.copy(alpha = SharedPdfHighlighterPalette.DefaultAlpha / 255f).toArgb()
-                val syncedArgb = SharedPdfAndroidHighlightColors.nearestArgb(nextArgb)
+                val nextColors = updateHighlighterDraft(slot, color)
                 onHighlighterPaletteChange(
-                    SharedPdfHighlighterPalette(highlighterColors).withColorAt(
-                        slotIndex = slot,
-                        colorArgb = nextArgb
-                    )
+                    SharedPdfHighlighterPalette(nextColors).sanitized()
                 )
-                onUpdate(annotation.copy(colorArgb = syncedArgb))
+                onUpdate(annotation.copy(colorArgb = nextArgb))
                 editingHighlighterSlot = null
+            },
+            resetColor = Color(SharedPdfHighlighterPalette.defaultColors.getOrElse(slot) {
+                SharedPdfHighlighterPalette.defaultColors.first()
+            }).copy(alpha = 1f),
+            stateKey = slot,
+            onLiveColorChange = { color ->
+                updateHighlighterDraft(slot, color)
             }
         ) { liveColor ->
             Row(
@@ -285,7 +420,7 @@ internal fun DesktopPdfAnnotationEditor(
                 horizontalArrangement = Arrangement.spacedBy(10.dp),
                 verticalAlignment = Alignment.CenterVertically
             ) {
-                highlighterColors.forEachIndexed { index, argb ->
+                highlighterDraftColors().forEachIndexed { index, argb ->
                     val color = if (index == slot) liveColor else Color(argb).copy(alpha = 1f)
                     Box(
                         modifier = Modifier
@@ -294,10 +429,14 @@ internal fun DesktopPdfAnnotationEditor(
                             .background(color)
                             .border(
                                 width = if (index == slot) 3.dp else 1.dp,
-                                color = if (index == slot) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.outline.copy(alpha = 0.35f),
+                                color = if (index == slot) {
+                                    MaterialTheme.colorScheme.primary
+                                } else {
+                                    MaterialTheme.colorScheme.outline.copy(alpha = 0.35f)
+                                },
                                 shape = RoundedCornerShape(21.dp)
                             )
-                            .clickable { editingHighlighterSlot = index },
+                            .clickable { openHighlighterEditor(index) },
                         contentAlignment = Alignment.Center
                     ) {
                         Text(
@@ -313,6 +452,265 @@ internal fun DesktopPdfAnnotationEditor(
     }
 }
 
+@Composable
+private fun DesktopPdfAnnotationSheetTabs(
+    selectedSection: DesktopPdfAnnotationSheetSection,
+    commentCount: Int,
+    onSectionChange: (DesktopPdfAnnotationSheetSection) -> Unit
+) {
+    Surface(
+        color = MaterialTheme.colorScheme.onSurface.copy(alpha = 0.06f),
+        shape = RoundedCornerShape(8.dp),
+        modifier = Modifier.fillMaxWidth()
+    ) {
+        Row(modifier = Modifier.padding(4.dp)) {
+            DesktopPdfAnnotationSheetTab(
+                label = readerString("label_note", "Note"),
+                selected = selectedSection == DesktopPdfAnnotationSheetSection.NOTE,
+                modifier = Modifier.weight(1f),
+                onClick = { onSectionChange(DesktopPdfAnnotationSheetSection.NOTE) }
+            )
+            DesktopPdfAnnotationSheetTab(
+                label = "${readerString("label_comments", "Comments")} ($commentCount)",
+                selected = selectedSection == DesktopPdfAnnotationSheetSection.COMMENTS,
+                modifier = Modifier.weight(1f),
+                onClick = { onSectionChange(DesktopPdfAnnotationSheetSection.COMMENTS) }
+            )
+        }
+    }
+}
+
+@Composable
+private fun DesktopPdfAnnotationSheetTab(
+    label: String,
+    selected: Boolean,
+    modifier: Modifier = Modifier,
+    onClick: () -> Unit
+) {
+    Surface(
+        color = if (selected) MaterialTheme.colorScheme.primary else Color.Transparent,
+        contentColor = if (selected) MaterialTheme.colorScheme.onPrimary else MaterialTheme.colorScheme.onSurface,
+        shape = RoundedCornerShape(6.dp),
+        modifier = modifier
+            .height(40.dp)
+            .clip(RoundedCornerShape(6.dp))
+            .clickable(onClick = onClick)
+    ) {
+        Box(contentAlignment = Alignment.Center, modifier = Modifier.fillMaxWidth().fillMaxHeight()) {
+            Text(
+                text = label,
+                style = MaterialTheme.typography.labelLarge,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis
+            )
+        }
+    }
+}
+
+@Composable
+private fun DesktopPdfHighlightCommentsEditor(
+    comments: List<SharedPdfAnnotationComment>,
+    commentText: String,
+    commentAuthor: String,
+    replyTargetId: String?,
+    editingCommentId: String?,
+    onCommentTextChange: (String) -> Unit,
+    onCommentAuthorChange: (String) -> Unit,
+    onReply: (SharedPdfAnnotationComment) -> Unit,
+    onCancelReply: () -> Unit,
+    onEdit: (SharedPdfAnnotationComment) -> Unit,
+    onCancelEdit: () -> Unit,
+    onDelete: (SharedPdfAnnotationComment) -> Unit,
+    onAddComment: () -> Unit
+) {
+    val visibleComments = comments.visiblePdfAnnotationComments()
+    val replyTarget = visibleComments.firstOrNull { it.id == replyTargetId }
+    val editingComment = visibleComments.firstOrNull { it.id == editingCommentId }
+
+    Column {
+        Column(
+            modifier = Modifier
+                .fillMaxWidth()
+                .heightIn(max = 220.dp)
+                .verticalScroll(rememberScrollState())
+        ) {
+            DesktopPdfHighlightCommentThread(
+                comments = visibleComments,
+                parentId = null,
+                depth = 0,
+                visitedIds = emptySet(),
+                onReply = onReply,
+                onEdit = onEdit,
+                onDelete = onDelete
+            )
+        }
+
+        if (editingComment != null || replyTarget != null) {
+            Row(
+                modifier = Modifier.fillMaxWidth().padding(top = 8.dp),
+                verticalAlignment = Alignment.CenterVertically
+            ) {
+                Text(
+                    text = if (editingComment != null) {
+                        readerString("label_editing_comment", "Editing comment")
+                    } else {
+                        readerString(
+                            "label_replying_to",
+                            "Replying to %1\$s",
+                            replyTarget?.author?.ifBlank { DEFAULT_SHARED_PDF_COMMENT_AUTHOR }.orEmpty()
+                        )
+                    },
+                    style = MaterialTheme.typography.labelMedium,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
+                    modifier = Modifier.weight(1f)
+                )
+                TextButton(onClick = if (editingComment != null) onCancelEdit else onCancelReply) {
+                    Text(readerString("action_cancel", "Cancel"))
+                }
+            }
+        }
+
+        SharedStableOutlinedTextField(
+            value = commentAuthor,
+            onValueChange = onCommentAuthorChange,
+            label = { Text(readerString("author", "Author")) },
+            modifier = Modifier.fillMaxWidth(),
+            singleLine = true,
+            shape = RoundedCornerShape(12.dp),
+            selectionKey = "comment-author-${editingCommentId ?: replyTargetId ?: "new"}"
+        )
+
+        Spacer(Modifier.height(8.dp))
+
+        SharedStableOutlinedTextField(
+            value = commentText,
+            onValueChange = onCommentTextChange,
+            placeholder = { Text(readerString("placeholder_add_comment", "Add a comment...")) },
+            modifier = Modifier.fillMaxWidth().heightIn(min = 88.dp),
+            minLines = 3,
+            maxLines = 4,
+            shape = RoundedCornerShape(12.dp),
+            selectionKey = "comment-text-${editingCommentId ?: replyTargetId ?: "new"}"
+        )
+
+        Row(
+            modifier = Modifier.fillMaxWidth().padding(top = 8.dp),
+            horizontalArrangement = Arrangement.End
+        ) {
+            TextButton(onClick = onAddComment, enabled = commentText.isNotBlank()) {
+                Text(
+                    readerString(
+                        if (editingComment != null) "action_save_comment" else "action_add_comment",
+                        if (editingComment != null) "Save Comment" else "Add Comment"
+                    )
+                )
+            }
+        }
+    }
+}
+
+@Composable
+private fun DesktopPdfHighlightCommentThread(
+    comments: List<SharedPdfAnnotationComment>,
+    parentId: String?,
+    depth: Int,
+    visitedIds: Set<String>,
+    onReply: (SharedPdfAnnotationComment) -> Unit,
+    onEdit: (SharedPdfAnnotationComment) -> Unit,
+    onDelete: (SharedPdfAnnotationComment) -> Unit
+) {
+    comments.pdfCommentChildren(parentId).forEach { comment ->
+        if (comment.id in visitedIds) return@forEach
+        DesktopPdfHighlightCommentItem(
+            comment = comment,
+            depth = depth,
+            onReply = { onReply(comment) },
+            onEdit = { onEdit(comment) },
+            onDelete = { onDelete(comment) }
+        )
+        DesktopPdfHighlightCommentThread(
+            comments = comments,
+            parentId = comment.id,
+            depth = depth + 1,
+            visitedIds = visitedIds + comment.id,
+            onReply = onReply,
+            onEdit = onEdit,
+            onDelete = onDelete
+        )
+    }
+}
+
+@Composable
+private fun DesktopPdfHighlightCommentItem(
+    comment: SharedPdfAnnotationComment,
+    depth: Int,
+    onReply: () -> Unit,
+    onEdit: () -> Unit,
+    onDelete: () -> Unit
+) {
+    val indentSize = (depth * 16).dp
+    Row(
+        modifier = Modifier
+            .fillMaxWidth()
+            .padding(start = indentSize, top = 6.dp, bottom = 6.dp)
+    ) {
+        if (depth > 0) {
+            Box(
+                modifier = Modifier
+                    .width(2.dp)
+                    .fillMaxHeight()
+                    .background(MaterialTheme.colorScheme.outlineVariant)
+            )
+            Spacer(modifier = Modifier.width(12.dp))
+        }
+        Column(modifier = Modifier.weight(1f)) {
+            Row(verticalAlignment = Alignment.CenterVertically) {
+                Text(
+                    text = comment.author.ifBlank { DEFAULT_SHARED_PDF_COMMENT_AUTHOR },
+                    style = MaterialTheme.typography.labelMedium,
+                    color = MaterialTheme.colorScheme.primary,
+                    fontWeight = FontWeight.Bold,
+                    maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
+                    modifier = Modifier.weight(1f)
+                )
+                val timestamp = comment.createdAt.formatDesktopPdfCommentTimestamp()
+                if (timestamp.isNotBlank()) {
+                    Text(
+                        text = timestamp,
+                        style = MaterialTheme.typography.labelSmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant
+                    )
+                }
+            }
+            Spacer(Modifier.height(2.dp))
+            Text(
+                text = comment.contents,
+                style = MaterialTheme.typography.bodyMedium,
+                color = MaterialTheme.colorScheme.onSurface
+            )
+            Row {
+                TextButton(onClick = onReply) {
+                    Text(readerString("action_reply", "Reply"))
+                }
+                TextButton(onClick = onEdit) {
+                    Text(readerString("label_edit", "Edit"))
+                }
+                TextButton(onClick = onDelete) {
+                    Text(readerString("action_delete", "Delete"), color = MaterialTheme.colorScheme.error)
+                }
+            }
+        }
+    }
+}
+
+private fun Long.formatDesktopPdfCommentTimestamp(): String {
+    if (this <= 0L) return ""
+    return runCatching {
+        DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT).format(Date(this))
+    }.getOrDefault("")
+}
+
 @Composable
 private fun DesktopBottomSheetToolButton(
     icon: ImageVector,

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfAppearance.kt

@@ -1,7 +1,6 @@
 package com.aryan.reader.desktop
 
 import androidx.compose.foundation.Canvas
-import androidx.compose.foundation.Image
 import androidx.compose.foundation.background
 import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
@@ -20,12 +19,17 @@ import androidx.compose.ui.graphics.BlendMode
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.ColorFilter
 import androidx.compose.ui.graphics.ColorMatrix
+import androidx.compose.ui.graphics.FilterQuality
 import androidx.compose.ui.graphics.ImageBitmap
 import androidx.compose.ui.graphics.ImageShader
 import androidx.compose.ui.graphics.ShaderBrush
 import androidx.compose.ui.graphics.TileMode
 import androidx.compose.ui.graphics.isSpecified
+import androidx.compose.ui.semantics.contentDescription
+import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.IntOffset
+import androidx.compose.ui.unit.IntSize
 import androidx.compose.ui.unit.dp
 import com.aryan.reader.shared.BuiltInPdfReaderThemes
 import com.aryan.reader.shared.PdfDisplayMode
@@ -33,9 +37,11 @@ import com.aryan.reader.shared.ReaderTheme
 import com.aryan.reader.shared.reader.ReaderSettings
 
 internal enum class DesktopPdfInspectorTab(val title: String) {
-    VIEW("View"),
+    APPEARANCE("Appearance"),
+    APP_THEME("App theme"),
+    VISUAL("Visual"),
     MARKUP("Markup"),
-    ASSIST("Assist")
+    TTS("TTS")
 }
 
 internal data class DesktopPdfThemeStyle(
@@ -56,15 +62,25 @@ internal fun DesktopPdfThemedPageImage(
     modifier: Modifier = Modifier
 ) {
     Box(modifier = modifier.background(themeStyle.pageBackgroundColor)) {
-        Image(
-            bitmap = bitmap,
-            contentDescription = contentDescription,
-            colorFilter = themeStyle.colorFilter,
-            modifier = Modifier.fillMaxSize()
-        )
         val textureBitmap = themeStyle.textureBitmap
-        if (textureBitmap != null && themeStyle.textureAlpha > 0f) {
-            Canvas(modifier = Modifier.fillMaxSize()) {
+        Canvas(
+            modifier = Modifier
+                .fillMaxSize()
+                .semantics { this.contentDescription = contentDescription }
+        ) {
+            drawImage(
+                image = bitmap,
+                srcOffset = IntOffset.Zero,
+                srcSize = IntSize(bitmap.width, bitmap.height),
+                dstOffset = IntOffset.Zero,
+                dstSize = IntSize(
+                    size.width.toInt().coerceAtLeast(1),
+                    size.height.toInt().coerceAtLeast(1)
+                ),
+                colorFilter = themeStyle.colorFilter,
+                filterQuality = FilterQuality.High
+            )
+            if (textureBitmap != null && themeStyle.textureAlpha > 0f) {
                 drawRect(
                     brush = ShaderBrush(ImageShader(textureBitmap, TileMode.Repeated, TileMode.Repeated)),
                     size = size,
@@ -77,7 +93,7 @@ internal fun DesktopPdfThemedPageImage(
 }
 
 internal fun ReaderSettings?.toDesktopPdfReaderSettings(): ReaderSettings {
-    val defaults = ReaderSettings(themeId = "no_theme")
+    val defaults = DesktopDefaultPdfReaderSettings
     val settings = this ?: defaults
     val themeId = settings.themeId
     val hasPdfTheme = BuiltInPdfReaderThemes.any { it.id == themeId }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfChromeUi.kt

@@ -35,7 +35,6 @@ import androidx.compose.material.icons.filled.VisibilityOff
 import androidx.compose.material.icons.filled.ZoomOut
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
-import androidx.compose.material3.IconButton
 import androidx.compose.material3.LinearProgressIndicator
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
@@ -49,6 +48,7 @@ import androidx.compose.ui.draw.clip
 import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.focus.focusRequester
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.luminance
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
@@ -56,6 +56,7 @@ import androidx.compose.ui.zIndex
 import com.aryan.reader.shared.SearchHighlightMode
 import com.aryan.reader.shared.pdf.SharedPdfSearchResult
 import com.aryan.reader.shared.ui.ReaderMinimalSlider
+import com.aryan.reader.shared.ui.ReaderTooltipIconButton
 import com.aryan.reader.shared.ui.SharedStableOutlinedTextField
 import com.aryan.reader.shared.ui.readerString
 import kotlinx.coroutines.delay
@@ -82,12 +83,11 @@ internal fun DesktopPdfFullscreenBottomChrome(
     val chromeBackground = MaterialTheme.colorScheme.surfaceVariant
     val chromeContent = MaterialTheme.colorScheme.onSurface
     val sliderActive = MaterialTheme.colorScheme.primary
-    val sliderInactive = MaterialTheme.colorScheme.surfaceVariant
+    val sliderInactive = chromeContent.copy(alpha = if (chromeBackground.luminance() > 0.5f) 0.44f else 0.52f)
     Surface(
         modifier = Modifier
-            .fillMaxWidth()
-            .padding(start = 16.dp, top = 6.dp, end = 16.dp, bottom = 0.dp),
-        shape = RoundedCornerShape(topStart = 6.dp, topEnd = 6.dp),
+            .fillMaxWidth(),
+        shape = RoundedCornerShape(0.dp),
         color = chromeBackground,
         contentColor = chromeContent,
         tonalElevation = 0.dp,
@@ -113,7 +113,11 @@ internal fun DesktopPdfFullscreenBottomChrome(
                 horizontalArrangement = Arrangement.spacedBy(8.dp),
                 verticalAlignment = Alignment.CenterVertically
             ) {
-                IconButton(onClick = onPrevious, enabled = canGoPrevious) {
+                ReaderTooltipIconButton(
+                    tooltip = readerString("desktop_previous_page", "Previous page"),
+                    onClick = onPrevious,
+                    enabled = canGoPrevious
+                ) {
                     Icon(
                         Icons.AutoMirrored.Filled.NavigateBefore,
                         contentDescription = readerString("desktop_previous_page", "Previous page"),
@@ -136,7 +140,11 @@ internal fun DesktopPdfFullscreenBottomChrome(
                     thumbColor = sliderActive,
                     modifier = Modifier.weight(1f)
                 )
-                IconButton(onClick = onNext, enabled = canGoNext) {
+                ReaderTooltipIconButton(
+                    tooltip = readerString("desktop_next_page", "Next page"),
+                    onClick = onNext,
+                    enabled = canGoNext
+                ) {
                     Icon(
                         Icons.AutoMirrored.Filled.NavigateNext,
                         contentDescription = readerString("desktop_next_page", "Next page"),
@@ -171,10 +179,10 @@ internal fun DesktopPdfBottomChrome(
     val chromeBackground = MaterialTheme.colorScheme.surfaceVariant
     val chromeContent = MaterialTheme.colorScheme.onSurface
     val sliderActive = MaterialTheme.colorScheme.primary
-    val sliderInactive = MaterialTheme.colorScheme.surfaceVariant
+    val sliderInactive = chromeContent.copy(alpha = if (chromeBackground.luminance() > 0.5f) 0.44f else 0.52f)
     Surface(
         modifier = Modifier.fillMaxWidth(),
-        shape = RoundedCornerShape(6.dp),
+        shape = RoundedCornerShape(0.dp),
         color = chromeBackground,
         contentColor = chromeContent,
         tonalElevation = 0.dp,
@@ -199,7 +207,11 @@ internal fun DesktopPdfBottomChrome(
                 horizontalArrangement = Arrangement.spacedBy(8.dp),
                 verticalAlignment = Alignment.CenterVertically
             ) {
-                IconButton(onClick = onPrevious, enabled = canGoPrevious) {
+                ReaderTooltipIconButton(
+                    tooltip = readerString("desktop_previous_page", "Previous page"),
+                    onClick = onPrevious,
+                    enabled = canGoPrevious
+                ) {
                     Icon(
                         Icons.AutoMirrored.Filled.NavigateBefore,
                         contentDescription = readerString("desktop_previous_page", "Previous page"),
@@ -230,7 +242,11 @@ internal fun DesktopPdfBottomChrome(
                     style = MaterialTheme.typography.labelSmall,
                     color = chromeContent.copy(alpha = 0.72f)
                 )
-                IconButton(onClick = onNext, enabled = canGoNext) {
+                ReaderTooltipIconButton(
+                    tooltip = readerString("desktop_next_page", "Next page"),
+                    onClick = onNext,
+                    enabled = canGoNext
+                ) {
                     Icon(
                         Icons.AutoMirrored.Filled.NavigateNext,
                         contentDescription = readerString("desktop_next_page", "Next page"),
@@ -298,7 +314,7 @@ internal fun DesktopPdfSearchTopBar(
 
     Surface(
         modifier = Modifier.fillMaxWidth(),
-        shape = RoundedCornerShape(6.dp),
+        shape = RoundedCornerShape(0.dp),
         color = MaterialTheme.colorScheme.surface,
         tonalElevation = 2.dp
     ) {
@@ -307,7 +323,11 @@ internal fun DesktopPdfSearchTopBar(
             verticalAlignment = Alignment.CenterVertically,
             horizontalArrangement = Arrangement.spacedBy(6.dp)
         ) {
-            IconButton(onClick = onClose, modifier = Modifier.size(36.dp)) {
+            ReaderTooltipIconButton(
+                tooltip = readerString("tooltip_close_search_desc", "Exit search and go back to the reader"),
+                onClick = onClose,
+                modifier = Modifier.size(36.dp)
+            ) {
                 Icon(Icons.Default.Close, contentDescription = readerString("content_desc_close_search", "Close search"))
             }
             SharedStableOutlinedTextField(
@@ -318,7 +338,10 @@ internal fun DesktopPdfSearchTopBar(
                 modifier = Modifier.weight(1f).focusRequester(focusRequester),
                 trailingIcon = if (query.isNotEmpty()) {
                     {
-                        IconButton(onClick = { onQueryChange("") }) {
+                        ReaderTooltipIconButton(
+                            tooltip = readerString("tooltip_clear_search_desc", "Erase your current search query and start over"),
+                            onClick = { onQueryChange("") }
+                        ) {
                             Icon(Icons.Default.Close, contentDescription = readerString("tooltip_clear_search", "Clear search"))
                         }
                     }
@@ -327,7 +350,16 @@ internal fun DesktopPdfSearchTopBar(
                 },
                 selectionKey = "desktop-pdf-search"
             )
-            IconButton(onClick = onToggleResults, modifier = Modifier.size(36.dp)) {
+            val resultsTooltip = if (showResultsPanel) {
+                readerString("tooltip_hide_results_desc", "Collapse the search results panel")
+            } else {
+                readerString("tooltip_show_results_desc", "Expand the panel to see all search matches")
+            }
+            ReaderTooltipIconButton(
+                tooltip = resultsTooltip,
+                onClick = onToggleResults,
+                modifier = Modifier.size(36.dp)
+            ) {
                 Icon(
                     if (showResultsPanel) Icons.Default.KeyboardArrowUp else Icons.Default.KeyboardArrowDown,
                     contentDescription = if (showResultsPanel) {
@@ -507,7 +539,15 @@ private fun DesktopPdfSearchNavigationPill(
             verticalAlignment = Alignment.CenterVertically,
             horizontalArrangement = Arrangement.spacedBy(4.dp)
         ) {
-            IconButton(onClick = onToggleHighlightMode, modifier = Modifier.size(36.dp)) {
+            ReaderTooltipIconButton(
+                tooltip = if (highlightMode == SearchHighlightMode.ALL) {
+                    readerString("desktop_show_current_match_only", "Show current match only")
+                } else {
+                    readerString("desktop_show_all_search_matches", "Show all search matches")
+                },
+                onClick = onToggleHighlightMode,
+                modifier = Modifier.size(36.dp)
+            ) {
                 Icon(
                     if (highlightMode == SearchHighlightMode.ALL) Icons.Default.Visibility else Icons.Default.VisibilityOff,
                     contentDescription = readerString("content_desc_toggle_search_highlights", "Toggle search highlights"),
@@ -518,7 +558,12 @@ private fun DesktopPdfSearchNavigationPill(
                     }
                 )
             }
-            IconButton(onClick = onPrevious, enabled = resultCount > 0, modifier = Modifier.size(36.dp)) {
+            ReaderTooltipIconButton(
+                tooltip = readerString("tooltip_prev_result_desc", "Jump to the previous search match in the document"),
+                onClick = onPrevious,
+                enabled = resultCount > 0,
+                modifier = Modifier.size(36.dp)
+            ) {
                 Icon(Icons.AutoMirrored.Filled.NavigateBefore, contentDescription = readerString("desktop_previous_search_result", "Previous search result"))
             }
             Text(
@@ -531,7 +576,12 @@ private fun DesktopPdfSearchNavigationPill(
                 fontWeight = FontWeight.SemiBold,
                 modifier = Modifier.clickable(onClick = onShowResults).padding(horizontal = 8.dp)
             )
-            IconButton(onClick = onNext, enabled = resultCount > 0, modifier = Modifier.size(36.dp)) {
+            ReaderTooltipIconButton(
+                tooltip = readerString("tooltip_next_result_desc", "Jump to the next search match in the document"),
+                onClick = onNext,
+                enabled = resultCount > 0,
+                modifier = Modifier.size(36.dp)
+            ) {
                 Icon(Icons.AutoMirrored.Filled.NavigateNext, contentDescription = readerString("desktop_next_search_result", "Next search result"))
             }
         }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfInspectorUi.kt

@@ -5,50 +5,46 @@ import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.ColumnScope
 import androidx.compose.foundation.layout.Row
-import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
-import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.horizontalScroll
 import androidx.compose.foundation.lazy.LazyListState
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.filled.ZoomIn
-import androidx.compose.material.icons.filled.ZoomOut
+import androidx.compose.material.icons.automirrored.filled.VolumeUp
+import androidx.compose.material.icons.filled.Edit
+import androidx.compose.material.icons.filled.Palette
+import androidx.compose.material.icons.filled.Tune
 import androidx.compose.material3.FilterChip
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
-import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.ScrollableTabRow
-import androidx.compose.material3.Slider
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Tab
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
-import androidx.compose.ui.text.font.FontWeight
-import androidx.compose.ui.text.style.TextAlign
+import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
 import com.aryan.reader.shared.BuiltInPdfReaderThemes
 import com.aryan.reader.shared.PdfDisplayMode
 import com.aryan.reader.shared.ReaderAiByokSettings
-import com.aryan.reader.shared.ReaderAutoScrollState
 import com.aryan.reader.shared.ReaderExtrasState
-import com.aryan.reader.shared.ReaderExternalLookupAction
-import com.aryan.reader.shared.ReaderTtsReadScope
+import com.aryan.reader.shared.ReaderTheme
 import com.aryan.reader.shared.ReaderTtsReplacementPreferences
 import com.aryan.reader.shared.pdf.PdfInkTool
-import com.aryan.reader.shared.pdf.PdfSpreadLayout
-import com.aryan.reader.shared.pdf.PdfZoomSpec
 import com.aryan.reader.shared.pdf.SharedPdfHighlighterPalette
 import com.aryan.reader.shared.pdf.SharedPdfRichTextController
 import com.aryan.reader.shared.pdf.SharedPdfTextStyleConfig
@@ -56,8 +52,6 @@ import com.aryan.reader.shared.pdf.currentSharedPdfTextStyleConfig
 import com.aryan.reader.shared.pdf.updateCurrentSharedPdfTextStyle
 import com.aryan.reader.shared.reader.ReaderPageSpreadMode
 import com.aryan.reader.shared.reader.ReaderSettings
-import com.aryan.reader.shared.ui.ReaderMinimalSlider
-import com.aryan.reader.shared.ui.SharedPdfAnnotationToolDock
 import com.aryan.reader.shared.ui.SharedPdfHighlighterPaletteEditor
 import com.aryan.reader.shared.ui.SharedPdfTextAnnotationDock
 import com.aryan.reader.shared.ui.SharedReaderThemeControls
@@ -68,131 +62,93 @@ import com.aryan.reader.shared.ui.sharedAcceleratedLazyWheelScroll
 @Composable
 internal fun DesktopPdfInspectorPanel(
     document: DesktopPdfDocument,
-    pageIndex: Int,
     displayMode: PdfDisplayMode,
     pdfReaderSettings: ReaderSettings,
+    appThemeControls: (@Composable () -> Unit)? = null,
+    customReaderThemes: List<ReaderTheme>,
+    onCustomReaderThemesChange: (List<ReaderTheme>) -> Unit,
     customTextureIds: List<String>,
     onImportTexture: ((ReaderSettings) -> ReaderSettings?)?,
     onReaderSettingsChange: (ReaderSettings) -> Unit,
-    zoomControlScale: Float,
-    zoomSpec: PdfZoomSpec,
-    isTextSelectionMode: Boolean,
     selectedTool: PdfInkTool,
     isRichTextMode: Boolean,
-    selectedColor: Int,
-    strokeWidth: Float,
-    pdfHighlighterColors: List<Int>,
     pdfHighlighterPalette: SharedPdfHighlighterPalette,
-    isHighlighterSnapEnabled: Boolean,
     effectiveTextStyleConfig: SharedPdfTextStyleConfig,
     richTextController: SharedPdfRichTextController,
     pdfExtrasState: ReaderExtrasState,
     aiByokSettings: ReaderAiByokSettings,
-    externalLookupAvailable: Boolean,
     cloudTtsFeatureAvailable: Boolean,
     ttsReplacementPreferences: ReaderTtsReplacementPreferences,
-    pageText: () -> String,
     onDisplayModeSelected: (PdfDisplayMode) -> Unit,
-    onPageScrub: (Float) -> Unit,
-    onPageScrubFinished: () -> Unit,
-    onZoomOut: () -> Unit,
-    onZoomIn: () -> Unit,
-    onZoomChange: (Float) -> Unit,
-    onSelectPanMode: () -> Unit,
-    onTextSelectionModeToggle: () -> Unit,
     onRichTextModeToggle: () -> Unit,
-    onToolSelected: (PdfInkTool) -> Unit,
-    onColorSelected: (Int) -> Unit,
-    onStrokeWidthChange: (Float) -> Unit,
-    onUndoPage: () -> Unit,
-    onClearPage: () -> Unit,
-    onHighlighterSnapChange: (Boolean) -> Unit,
     onHighlighterPaletteChange: (SharedPdfHighlighterPalette) -> Unit,
     onTextStyleChange: (SharedPdfTextStyleConfig) -> Unit,
-    onExternalLookup: (ReaderExternalLookupAction, String) -> Unit,
-    onOpenAiHub: (() -> Unit)? = null,
-    onCloudTtsStart: (ReaderTtsReadScope) -> Unit,
-    onCloudTtsPauseResume: () -> Unit,
-    onCloudTtsStop: () -> Unit,
     onCloudTtsClearCache: () -> Unit,
-    onAutoScrollChange: (ReaderAutoScrollState) -> Unit,
+    onCloudTtsVoiceChange: (String) -> Unit,
     onTtsReplacementPreferencesChange: (ReaderTtsReplacementPreferences) -> Unit
 ) {
-    var selectedPdfInspectorTab by remember(document.handleId) { mutableStateOf(DesktopPdfInspectorTab.VIEW) }
-    val viewInspectorListState = rememberLazyListState()
+    val inspectorTabs = remember(appThemeControls != null) {
+        desktopPdfInspectorTabs(appThemeControlsAvailable = appThemeControls != null)
+    }
+    var selectedPdfInspectorTab by remember(document.handleId) { mutableStateOf(DesktopPdfInspectorTab.VISUAL) }
+    LaunchedEffect(inspectorTabs) {
+        if (selectedPdfInspectorTab !in inspectorTabs) {
+            selectedPdfInspectorTab = DesktopPdfInspectorTab.VISUAL.takeIf { it in inspectorTabs }
+                ?: inspectorTabs.first()
+        }
+    }
+    val appThemeInspectorListState = rememberLazyListState()
+    val appearanceInspectorListState = rememberLazyListState()
+    val visualInspectorListState = rememberLazyListState()
     val markupInspectorListState = rememberLazyListState()
-    val assistInspectorListState = rememberLazyListState()
+    val ttsInspectorListState = rememberLazyListState()
     val pdfInspectorListState = when (selectedPdfInspectorTab) {
-        DesktopPdfInspectorTab.VIEW -> viewInspectorListState
+        DesktopPdfInspectorTab.APP_THEME -> appThemeInspectorListState
+        DesktopPdfInspectorTab.APPEARANCE -> appearanceInspectorListState
+        DesktopPdfInspectorTab.VISUAL -> visualInspectorListState
         DesktopPdfInspectorTab.MARKUP -> markupInspectorListState
-        DesktopPdfInspectorTab.ASSIST -> assistInspectorListState
+        DesktopPdfInspectorTab.TTS -> ttsInspectorListState
     }
 
     Surface(
-        modifier = Modifier
-            .width(340.dp)
-            .fillMaxHeight(),
-        color = MaterialTheme.colorScheme.surfaceVariant,
-        shape = RoundedCornerShape(8.dp)
+        modifier = Modifier.fillMaxSize(),
+        color = MaterialTheme.colorScheme.surface,
+        shape = RoundedCornerShape(0.dp)
     ) {
         Column(modifier = Modifier.fillMaxSize()) {
             DesktopPdfInspectorHeader(
+                tabs = inspectorTabs,
                 selectedTab = selectedPdfInspectorTab,
                 onTabSelected = { selectedPdfInspectorTab = it }
             )
             HorizontalDivider()
             DesktopPdfInspectorContent(
                 document = document,
-                pageIndex = pageIndex,
                 displayMode = displayMode,
                 pdfReaderSettings = pdfReaderSettings,
+                appThemeControls = appThemeControls,
+                customReaderThemes = customReaderThemes,
+                onCustomReaderThemesChange = onCustomReaderThemesChange,
                 customTextureIds = customTextureIds,
                 onImportTexture = onImportTexture,
                 onReaderSettingsChange = onReaderSettingsChange,
-                zoomControlScale = zoomControlScale,
-                zoomSpec = zoomSpec,
-                isTextSelectionMode = isTextSelectionMode,
                 selectedTool = selectedTool,
                 isRichTextMode = isRichTextMode,
-                selectedColor = selectedColor,
-                strokeWidth = strokeWidth,
-                pdfHighlighterColors = pdfHighlighterColors,
                 pdfHighlighterPalette = pdfHighlighterPalette,
-                isHighlighterSnapEnabled = isHighlighterSnapEnabled,
                 effectiveTextStyleConfig = effectiveTextStyleConfig,
                 richTextController = richTextController,
                 pdfExtrasState = pdfExtrasState,
                 aiByokSettings = aiByokSettings,
-                externalLookupAvailable = externalLookupAvailable,
                 cloudTtsFeatureAvailable = cloudTtsFeatureAvailable,
                 ttsReplacementPreferences = ttsReplacementPreferences,
-                pageText = pageText,
                 selectedTab = selectedPdfInspectorTab,
                 listState = pdfInspectorListState,
                 onDisplayModeSelected = onDisplayModeSelected,
-                onPageScrub = onPageScrub,
-                onPageScrubFinished = onPageScrubFinished,
-                onZoomOut = onZoomOut,
-                onZoomIn = onZoomIn,
-                onZoomChange = onZoomChange,
-                onSelectPanMode = onSelectPanMode,
-                onTextSelectionModeToggle = onTextSelectionModeToggle,
                 onRichTextModeToggle = onRichTextModeToggle,
-                onToolSelected = onToolSelected,
-                onColorSelected = onColorSelected,
-                onStrokeWidthChange = onStrokeWidthChange,
-                onUndoPage = onUndoPage,
-                onClearPage = onClearPage,
-                onHighlighterSnapChange = onHighlighterSnapChange,
                 onHighlighterPaletteChange = onHighlighterPaletteChange,
                 onTextStyleChange = onTextStyleChange,
-                onExternalLookup = onExternalLookup,
-                onOpenAiHub = onOpenAiHub,
-                onCloudTtsStart = onCloudTtsStart,
-                onCloudTtsPauseResume = onCloudTtsPauseResume,
-                onCloudTtsStop = onCloudTtsStop,
                 onCloudTtsClearCache = onCloudTtsClearCache,
-                onAutoScrollChange = onAutoScrollChange,
+                onCloudTtsVoiceChange = onCloudTtsVoiceChange,
                 onTtsReplacementPreferencesChange = onTtsReplacementPreferencesChange
             )
         }
@@ -201,32 +157,33 @@ internal fun DesktopPdfInspectorPanel(
 
 @Composable
 private fun DesktopPdfInspectorHeader(
+    tabs: List<DesktopPdfInspectorTab>,
     selectedTab: DesktopPdfInspectorTab,
     onTabSelected: (DesktopPdfInspectorTab) -> Unit
 ) {
-    Column(
-        modifier = Modifier.padding(start = 12.dp, top = 12.dp, end = 12.dp),
-        verticalArrangement = Arrangement.spacedBy(8.dp)
+    ScrollableTabRow(
+        selectedTabIndex = tabs.indexOf(selectedTab).coerceAtLeast(0),
+        edgePadding = 0.dp,
+        modifier = Modifier.fillMaxWidth()
     ) {
-        Text(readerString("desktop_pdf_tools", "PDF tools"), style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.Bold)
-        ScrollableTabRow(
-            selectedTabIndex = selectedTab.ordinal,
-            edgePadding = 0.dp,
-            modifier = Modifier.fillMaxWidth()
-        ) {
-            DesktopPdfInspectorTab.values().forEach { tab ->
-                Tab(
-                    selected = selectedTab == tab,
-                    onClick = { onTabSelected(tab) },
-                    text = {
-                        Text(
-                            tab.localizedTitle(),
-                            maxLines = 1,
-                            overflow = TextOverflow.Ellipsis
-                        )
-                    }
-                )
-            }
+        tabs.forEach { tab ->
+            Tab(
+                selected = selectedTab == tab,
+                onClick = { onTabSelected(tab) },
+                icon = {
+                    Icon(
+                        tab.icon(),
+                        contentDescription = null
+                    )
+                },
+                text = {
+                    Text(
+                        tab.localizedTitle(),
+                        maxLines = 1,
+                        overflow = TextOverflow.Ellipsis
+                    )
+                }
+            )
         }
     }
 }
@@ -234,56 +191,31 @@ private fun DesktopPdfInspectorHeader(
 @Composable
 private fun ColumnScope.DesktopPdfInspectorContent(
     document: DesktopPdfDocument,
-    pageIndex: Int,
     displayMode: PdfDisplayMode,
     pdfReaderSettings: ReaderSettings,
+    appThemeControls: (@Composable () -> Unit)?,
+    customReaderThemes: List<ReaderTheme>,
+    onCustomReaderThemesChange: (List<ReaderTheme>) -> Unit,
     customTextureIds: List<String>,
     onImportTexture: ((ReaderSettings) -> ReaderSettings?)?,
     onReaderSettingsChange: (ReaderSettings) -> Unit,
-    zoomControlScale: Float,
-    zoomSpec: PdfZoomSpec,
-    isTextSelectionMode: Boolean,
     selectedTool: PdfInkTool,
     isRichTextMode: Boolean,
-    selectedColor: Int,
-    strokeWidth: Float,
-    pdfHighlighterColors: List<Int>,
     pdfHighlighterPalette: SharedPdfHighlighterPalette,
-    isHighlighterSnapEnabled: Boolean,
     effectiveTextStyleConfig: SharedPdfTextStyleConfig,
     richTextController: SharedPdfRichTextController,
     pdfExtrasState: ReaderExtrasState,
     aiByokSettings: ReaderAiByokSettings,
-    externalLookupAvailable: Boolean,
     cloudTtsFeatureAvailable: Boolean,
     ttsReplacementPreferences: ReaderTtsReplacementPreferences,
-    pageText: () -> String,
     selectedTab: DesktopPdfInspectorTab,
     listState: LazyListState,
     onDisplayModeSelected: (PdfDisplayMode) -> Unit,
-    onPageScrub: (Float) -> Unit,
-    onPageScrubFinished: () -> Unit,
-    onZoomOut: () -> Unit,
-    onZoomIn: () -> Unit,
-    onZoomChange: (Float) -> Unit,
-    onSelectPanMode: () -> Unit,
-    onTextSelectionModeToggle: () -> Unit,
     onRichTextModeToggle: () -> Unit,
-    onToolSelected: (PdfInkTool) -> Unit,
-    onColorSelected: (Int) -> Unit,
-    onStrokeWidthChange: (Float) -> Unit,
-    onUndoPage: () -> Unit,
-    onClearPage: () -> Unit,
-    onHighlighterSnapChange: (Boolean) -> Unit,
     onHighlighterPaletteChange: (SharedPdfHighlighterPalette) -> Unit,
     onTextStyleChange: (SharedPdfTextStyleConfig) -> Unit,
-    onExternalLookup: (ReaderExternalLookupAction, String) -> Unit,
-    onOpenAiHub: (() -> Unit)?,
-    onCloudTtsStart: (ReaderTtsReadScope) -> Unit,
-    onCloudTtsPauseResume: () -> Unit,
-    onCloudTtsStop: () -> Unit,
     onCloudTtsClearCache: () -> Unit,
-    onAutoScrollChange: (ReaderAutoScrollState) -> Unit,
+    onCloudTtsVoiceChange: (String) -> Unit,
     onTtsReplacementPreferencesChange: (ReaderTtsReplacementPreferences) -> Unit
 ) {
     Box(modifier = Modifier.weight(1f).fillMaxWidth()) {
@@ -296,14 +228,54 @@ private fun ColumnScope.DesktopPdfInspectorContent(
             verticalArrangement = Arrangement.spacedBy(14.dp)
         ) {
             when (selectedTab) {
-                DesktopPdfInspectorTab.VIEW -> {
+                DesktopPdfInspectorTab.APP_THEME -> {
+                    appThemeControls?.let { controls ->
+                        item {
+                            controls()
+                        }
+                    }
+                }
+                DesktopPdfInspectorTab.APPEARANCE -> {
                     item {
-                        DesktopPdfInspectorSection(readerString("label_reading", "Reading")) {
-                            Row(horizontalArrangement = Arrangement.spacedBy(8.dp), verticalAlignment = Alignment.CenterVertically) {
+                        DesktopPdfInspectorSection(readerString("desktop_pdf_theme", "PDF theme")) {
+                            SharedReaderThemeControls(
+                                settings = pdfReaderSettings,
+                                builtInThemes = BuiltInPdfReaderThemes,
+                                customThemes = customReaderThemes,
+                                onCustomThemesChange = onCustomReaderThemesChange,
+                                customTextureIds = customTextureIds,
+                                onImportTexture = onImportTexture,
+                                texturePreviewContent = { textureId, previewModifier ->
+                                    DesktopReaderTexturePreview(textureId = textureId, modifier = previewModifier)
+                                },
+                                onSettingsChange = onReaderSettingsChange
+                            )
+                        }
+                    }
+                }
+                DesktopPdfInspectorTab.VISUAL -> {
+                    item {
+                        DesktopPdfInspectorSection(readerString("visual_options_title", "Visual options")) {
+                            Row(
+                                horizontalArrangement = Arrangement.spacedBy(8.dp),
+                                verticalAlignment = Alignment.CenterVertically,
+                                modifier = Modifier.horizontalScroll(rememberScrollState())
+                            ) {
                                 FilterChip(
-                                    selected = displayMode == PdfDisplayMode.PAGINATION,
-                                    onClick = { onDisplayModeSelected(PdfDisplayMode.PAGINATION) },
-                                    label = { Text(readerString("desktop_page", "Page")) }
+                                    selected = displayMode == PdfDisplayMode.PAGINATION && !pdfReaderSettings.rightToLeftPagination,
+                                    onClick = {
+                                        onReaderSettingsChange(pdfReaderSettings.copy(rightToLeftPagination = false))
+                                        onDisplayModeSelected(PdfDisplayMode.PAGINATION)
+                                    },
+                                    label = { Text(readerString("menu_reading_mode_paginated", "Paginated (left-to-right)")) }
+                                )
+                                FilterChip(
+                                    selected = displayMode == PdfDisplayMode.PAGINATION && pdfReaderSettings.rightToLeftPagination,
+                                    onClick = {
+                                        onReaderSettingsChange(pdfReaderSettings.copy(rightToLeftPagination = true))
+                                        onDisplayModeSelected(PdfDisplayMode.PAGINATION)
+                                    },
+                                    label = { Text(readerString("menu_right_to_left_pagination", "Paginated (right-to-left)")) }
                                 )
                                 FilterChip(
                                     selected = displayMode == PdfDisplayMode.VERTICAL_SCROLL,
@@ -348,53 +320,11 @@ private fun ColumnScope.DesktopPdfInspectorContent(
                                     )
                                 }
                             }
-                        }
-                    }
-                    item {
-                        DesktopPdfInspectorSection(readerString("visual_options_progress_bar_position", "Position")) {
-                            val pageRange = if (displayMode == PdfDisplayMode.PAGINATION) {
-                                PdfSpreadLayout.pageRangeLabel(pageIndex, document.pageCount, pdfReaderSettings)
-                            } else {
-                                "${pageIndex + 1}"
-                            }
-                            Text(
-                                if ('-' in pageRange) {
-                                    readerString("desktop_pdf_pages_of_count", "Pages %1\$s of %2\$d", pageRange, document.pageCount)
-                                } else {
-                                    readerString("desktop_pdf_page_of_count", "Page %1\$s of %2\$d", pageRange, document.pageCount)
-                                },
-                                color = MaterialTheme.colorScheme.onSurfaceVariant
-                            )
-                            if (document.pageCount > 1) {
-                                ReaderMinimalSlider(
-                                    value = pageIndex.toFloat(),
-                                    onValueChange = onPageScrub,
-                                    onValueChangeFinished = onPageScrubFinished,
-                                    valueRange = 0f..(document.pageCount - 1).toFloat()
-                                )
-                            }
-                        }
-                    }
-                    item {
-                        DesktopPdfInspectorSection(readerString("app_theme_appearance", "Appearance")) {
-                            SharedReaderThemeControls(
-                                settings = pdfReaderSettings,
-                                builtInThemes = BuiltInPdfReaderThemes,
-                                customTextureIds = customTextureIds,
-                                onImportTexture = onImportTexture,
-                                onSettingsChange = onReaderSettingsChange
-                            )
-                            HorizontalDivider(modifier = Modifier.padding(vertical = 4.dp))
-                            Text(
-                                readerString("visual_options_title", "Visual options"),
-                                style = MaterialTheme.typography.labelLarge,
-                                fontWeight = FontWeight.SemiBold
-                            )
                             DesktopPdfVisualOptionSwitch(
                                 title = readerString("visual_options_remove_page_gap", "Remove gap between pages"),
                                 description = readerString(
                                     "desktop_remove_gap_between_pages_desc",
-                                    "Applies to vertical reading mode."
+                                    "Applies to vertical reading and two-page spreads."
                                 ),
                                 checked = !pdfReaderSettings.pdfVerticalPageGapVisible,
                                 onCheckedChange = { removeGap ->
@@ -418,43 +348,11 @@ private fun ColumnScope.DesktopPdfInspectorContent(
                             )
                         }
                     }
-                    item {
-                        DesktopPdfInspectorSection(readerString("desktop_zoom", "Zoom")) {
-                            Row(horizontalArrangement = Arrangement.spacedBy(8.dp), verticalAlignment = Alignment.CenterVertically) {
-                                IconButton(onClick = onZoomOut) {
-                                    Icon(Icons.Default.ZoomOut, contentDescription = readerString("desktop_zoom_out", "Zoom out"))
-                                }
-                                Text(
-                                    "${(zoomControlScale * 100).toInt()}%",
-                                    modifier = Modifier.weight(1f),
-                                    textAlign = TextAlign.Center
-                                )
-                                IconButton(onClick = onZoomIn) {
-                                    Icon(Icons.Default.ZoomIn, contentDescription = readerString("desktop_zoom_in", "Zoom in"))
-                                }
-                            }
-                            Slider(
-                                value = zoomControlScale,
-                                onValueChange = onZoomChange,
-                                valueRange = zoomSpec.min..zoomSpec.max
-                            )
-                        }
-                    }
                 }
                 DesktopPdfInspectorTab.MARKUP -> {
                     item {
-                        DesktopPdfInspectorSection(readerString("desktop_interaction", "Interaction")) {
+                        DesktopPdfInspectorSection(readerString("desktop_document_text", "Document text")) {
                             Row(horizontalArrangement = Arrangement.spacedBy(8.dp), verticalAlignment = Alignment.CenterVertically) {
-                                FilterChip(
-                                    selected = !isTextSelectionMode && selectedTool == PdfInkTool.NONE && !isRichTextMode,
-                                    onClick = onSelectPanMode,
-                                    label = { Text(readerString("desktop_pan", "Pan")) }
-                                )
-                                FilterChip(
-                                    selected = isTextSelectionMode,
-                                    onClick = onTextSelectionModeToggle,
-                                    label = { Text(readerString("desktop_select_text", "Select text")) }
-                                )
                                 FilterChip(
                                     selected = isRichTextMode,
                                     onClick = onRichTextModeToggle,
@@ -463,24 +361,6 @@ private fun ColumnScope.DesktopPdfInspectorContent(
                             }
                         }
                     }
-                    item {
-                        DesktopPdfInspectorSection(readerString("desktop_annotation_tools", "Annotation tools")) {
-                            SharedPdfAnnotationToolDock(
-                                selectedTool = selectedTool,
-                                selectedColor = selectedColor,
-                                strokeWidth = strokeWidth,
-                                tools = DesktopPdfAnnotationTools,
-                                highlighterPalette = pdfHighlighterColors,
-                                onToolSelected = onToolSelected,
-                                onColorSelected = onColorSelected,
-                                onStrokeWidthChange = onStrokeWidthChange,
-                                onUndo = onUndoPage,
-                                onClearPage = onClearPage,
-                                isHighlighterSnapEnabled = isHighlighterSnapEnabled,
-                                onHighlighterSnapChange = onHighlighterSnapChange
-                            )
-                        }
-                    }
                     item {
                         DesktopPdfInspectorSection(readerString("desktop_highlighter_palette", "Highlighter palette")) {
                             SharedPdfHighlighterPaletteEditor(
@@ -510,21 +390,14 @@ private fun ColumnScope.DesktopPdfInspectorContent(
                         }
                     }
                 }
-                DesktopPdfInspectorTab.ASSIST -> {
+                DesktopPdfInspectorTab.TTS -> {
                     item {
-                        DesktopPdfExtrasPanel(
-                            pageText = pageText(),
+                        DesktopPdfTtsPanel(
                             extrasState = pdfExtrasState,
                             aiByokSettings = aiByokSettings,
-                            externalLookupAvailable = externalLookupAvailable,
                             cloudTtsFeatureAvailable = cloudTtsFeatureAvailable,
-                            onExternalLookup = onExternalLookup,
-                            onOpenAiHub = onOpenAiHub,
-                            onCloudTtsStart = onCloudTtsStart,
-                            onCloudTtsPauseResume = onCloudTtsPauseResume,
-                            onCloudTtsStop = onCloudTtsStop,
                             onCloudTtsClearCache = onCloudTtsClearCache,
-                            onAutoScrollChange = onAutoScrollChange,
+                            onCloudTtsVoiceChange = onCloudTtsVoiceChange,
                             ttsReplacementPreferences = ttsReplacementPreferences,
                             ttsReplacementBookId = document.path,
                             onTtsReplacementPreferencesChange = onTtsReplacementPreferencesChange
@@ -543,8 +416,29 @@ private fun ColumnScope.DesktopPdfInspectorContent(
 @Composable
 private fun DesktopPdfInspectorTab.localizedTitle(): String {
     return when (this) {
-        DesktopPdfInspectorTab.VIEW -> readerString("desktop_view", "View")
+        DesktopPdfInspectorTab.APP_THEME -> readerString("app_theme_title", "App theme")
+        DesktopPdfInspectorTab.APPEARANCE -> readerString("desktop_pdf_theme", "PDF theme")
+        DesktopPdfInspectorTab.VISUAL -> readerString("visual_options_title", "Visual")
         DesktopPdfInspectorTab.MARKUP -> readerString("desktop_markup", "Markup")
-        DesktopPdfInspectorTab.ASSIST -> readerString("desktop_assist", "Assist")
+        DesktopPdfInspectorTab.TTS -> readerString("menu_tts_settings", "TTS")
+    }
+}
+
+private fun DesktopPdfInspectorTab.icon(): ImageVector {
+    return when (this) {
+        DesktopPdfInspectorTab.APP_THEME -> Icons.Default.Palette
+        DesktopPdfInspectorTab.APPEARANCE -> Icons.Default.Palette
+        DesktopPdfInspectorTab.VISUAL -> Icons.Default.Tune
+        DesktopPdfInspectorTab.MARKUP -> Icons.Default.Edit
+        DesktopPdfInspectorTab.TTS -> Icons.AutoMirrored.Filled.VolumeUp
+    }
+}
+
+private fun desktopPdfInspectorTabs(appThemeControlsAvailable: Boolean): List<DesktopPdfInspectorTab> {
+    return buildList {
+        add(DesktopPdfInspectorTab.APPEARANCE)
+        if (appThemeControlsAvailable) add(DesktopPdfInspectorTab.APP_THEME)
+        add(DesktopPdfInspectorTab.VISUAL)
+        add(DesktopPdfInspectorTab.TTS)
     }
 }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfKeyCommands.kt

@@ -23,7 +23,8 @@ internal enum class DesktopPdfKeyCommand {
 
 internal fun KeyEvent.desktopPdfKeyCommandOrNull(
     fullscreen: Boolean,
-    editingText: Boolean
+    editingText: Boolean,
+    rightToLeftPagination: Boolean = false
 ): DesktopPdfKeyCommand? {
     if (type != KeyEventType.KeyDown) return null
     if (fullscreen && key == Key.Escape) {
@@ -33,8 +34,16 @@ internal fun KeyEvent.desktopPdfKeyCommandOrNull(
         return null
     }
     return when {
-        key == Key.DirectionLeft -> DesktopPdfKeyCommand.PREVIOUS_PAGE
-        key == Key.DirectionRight -> DesktopPdfKeyCommand.NEXT_PAGE
+        key == Key.DirectionLeft -> if (rightToLeftPagination) {
+            DesktopPdfKeyCommand.NEXT_PAGE
+        } else {
+            DesktopPdfKeyCommand.PREVIOUS_PAGE
+        }
+        key == Key.DirectionRight -> if (rightToLeftPagination) {
+            DesktopPdfKeyCommand.PREVIOUS_PAGE
+        } else {
+            DesktopPdfKeyCommand.NEXT_PAGE
+        }
         key == Key.DirectionUp -> DesktopPdfKeyCommand.SCROLL_UP
         key == Key.DirectionDown -> DesktopPdfKeyCommand.SCROLL_DOWN
         key == Key.PageUp -> DesktopPdfKeyCommand.PREVIOUS_PAGE
@@ -50,7 +59,8 @@ internal fun KeyEvent.desktopPdfKeyCommandOrNull(
 
 internal fun AwtKeyEvent.desktopPdfKeyCommandOrNull(
     fullscreen: Boolean,
-    editingText: Boolean
+    editingText: Boolean,
+    rightToLeftPagination: Boolean = false
 ): DesktopPdfKeyCommand? {
     if (id != AwtKeyEvent.KEY_PRESSED) return null
     if (fullscreen && keyCode == AwtKeyEvent.VK_ESCAPE) {
@@ -60,8 +70,16 @@ internal fun AwtKeyEvent.desktopPdfKeyCommandOrNull(
         return null
     }
     return when (keyCode) {
-        AwtKeyEvent.VK_LEFT -> DesktopPdfKeyCommand.PREVIOUS_PAGE
-        AwtKeyEvent.VK_RIGHT -> DesktopPdfKeyCommand.NEXT_PAGE
+        AwtKeyEvent.VK_LEFT -> if (rightToLeftPagination) {
+            DesktopPdfKeyCommand.NEXT_PAGE
+        } else {
+            DesktopPdfKeyCommand.PREVIOUS_PAGE
+        }
+        AwtKeyEvent.VK_RIGHT -> if (rightToLeftPagination) {
+            DesktopPdfKeyCommand.PREVIOUS_PAGE
+        } else {
+            DesktopPdfKeyCommand.NEXT_PAGE
+        }
         AwtKeyEvent.VK_UP -> DesktopPdfKeyCommand.SCROLL_UP
         AwtKeyEvent.VK_DOWN -> DesktopPdfKeyCommand.SCROLL_DOWN
         AwtKeyEvent.VK_PAGE_UP -> DesktopPdfKeyCommand.PREVIOUS_PAGE

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfNavigationUi.kt

@@ -26,6 +26,7 @@ import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.lazy.rememberLazyListState
+import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
@@ -38,9 +39,11 @@ import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.DropdownMenu
 import androidx.compose.material3.DropdownMenuItem
 import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.FilterChip
 import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
+import androidx.compose.material3.ListItem
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.ScrollableTabRow
 import androidx.compose.material3.Surface
@@ -59,6 +62,7 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.text.font.FontStyle
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
@@ -66,7 +70,6 @@ import com.aryan.reader.shared.PdfTocEntry
 import com.aryan.reader.shared.pdf.PdfAnnotationKind
 import com.aryan.reader.shared.pdf.SharedPdfAnnotation
 import com.aryan.reader.shared.pdf.SharedPdfBookmark
-import com.aryan.reader.shared.pdf.SharedPdfEmbeddedAnnotation
 import com.aryan.reader.shared.ui.SharedReaderVerticalScrollbar
 import com.aryan.reader.shared.ui.readerString
 import com.aryan.reader.shared.ui.sharedAcceleratedLazyWheelScroll
@@ -199,27 +202,28 @@ internal fun desktopVisiblePdfTocEntries(
     return result
 }
 
+internal fun desktopPdfSidebarHighlights(annotations: List<SharedPdfAnnotation>): List<SharedPdfAnnotation> {
+    return annotations
+        .filter { it.kind == PdfAnnotationKind.HIGHLIGHT }
+        .sortedBy { it.pageIndex }
+}
+
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
 internal fun DesktopPdfNavigationSidebar(
     document: DesktopPdfDocument,
     pageIndex: Int,
-    sortedAnnotations: List<SharedPdfAnnotation>,
-    sortedEmbeddedAnnotations: List<SharedPdfEmbeddedAnnotation>,
+    sortedHighlights: List<SharedPdfAnnotation>,
     bookmarks: List<SharedPdfBookmark>,
-    selectedAnnotationId: String?,
-    selectedEmbeddedAnnotationId: String?,
     onPageSelected: (Int) -> Unit,
     onAnnotationOpened: (SharedPdfAnnotation) -> Unit,
     onAnnotationSelected: (SharedPdfAnnotation) -> Unit,
-    onAnnotationDeleted: (SharedPdfAnnotation) -> Unit,
-    onEmbeddedAnnotationOpened: (SharedPdfEmbeddedAnnotation) -> Unit,
-    onEmbeddedAnnotationSelected: (SharedPdfEmbeddedAnnotation) -> Unit
+    onAnnotationDeleted: (SharedPdfAnnotation) -> Unit
 ) {
     val documentHandleId = document.handleId
     val tabs = listOf(
         readerString("desktop_toc", "TOC"),
-        readerString("tab_annotations", "Annotations"),
+        readerString("tab_highlights", "Highlights"),
         readerString("tab_bookmarks", "Bookmarks"),
         readerString("tab_pages", "Pages")
     )
@@ -344,180 +348,158 @@ internal fun DesktopPdfNavigationSidebar(
                     }
                 }
                 1 -> {
-                    if (sortedAnnotations.isEmpty() && sortedEmbeddedAnnotations.isEmpty()) {
-                        DesktopPdfNavigationEmpty(readerString("desktop_no_annotations_yet", "No annotations yet"))
+                    if (sortedHighlights.isEmpty()) {
+                        DesktopPdfNavigationEmpty(readerString("no_highlights_yet", "No highlights yet"))
                     } else {
-                        val annotationsListState = rememberLazyListState()
-                        var annotationMenuExpandedFor by remember { mutableStateOf<SharedPdfAnnotation?>(null) }
-                        var embeddedAnnotationMenuExpandedFor by remember { mutableStateOf<SharedPdfEmbeddedAnnotation?>(null) }
-                        var deleteAnnotationConfirmFor by remember { mutableStateOf<SharedPdfAnnotation?>(null) }
-                        Box(modifier = Modifier.fillMaxSize()) {
-                            LazyColumn(
-                                state = annotationsListState,
-                                modifier = Modifier
-                                    .fillMaxSize()
-                                    .sharedAcceleratedLazyWheelScroll(annotationsListState)
-                                    .padding(start = 12.dp, top = 12.dp, bottom = 12.dp, end = 24.dp),
-                                verticalArrangement = Arrangement.spacedBy(8.dp)
-                            ) {
-                                items(sortedAnnotations, key = { "nav_annotation_${it.id}" }) { annotation ->
-                                    Surface(
-                                        color = if (annotation.id == selectedAnnotationId) {
-                                            MaterialTheme.colorScheme.primaryContainer
-                                        } else {
-                                            MaterialTheme.colorScheme.surfaceVariant
-                                        },
-                                        shape = RoundedCornerShape(6.dp),
-                                        modifier = Modifier.fillMaxWidth()
-                                    ) {
-                                        Row(verticalAlignment = Alignment.CenterVertically) {
-                                            Column(
-                                                modifier = Modifier
-                                                    .weight(1f)
-                                                    .clickable { onAnnotationOpened(annotation) }
-                                                    .padding(8.dp),
-                                                verticalArrangement = Arrangement.spacedBy(3.dp)
-                                            ) {
-                                                Text(
-                                                    annotation.desktopLabel(),
-                                                    fontWeight = FontWeight.SemiBold,
-                                                    maxLines = 1,
-                                                    overflow = TextOverflow.Ellipsis
-                                                )
-                                                Text(
-                                                    readerString("pdf_page_short", "Page %1\$d", annotation.pageIndex + 1),
-                                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                                                    style = MaterialTheme.typography.bodySmall
-                                                )
-                                                annotation.note?.takeIf { it.isNotBlank() }?.let { note ->
-                                                    Text(
-                                                        note,
-                                                        color = MaterialTheme.colorScheme.onSurfaceVariant,
-                                                        style = MaterialTheme.typography.bodySmall,
-                                                        maxLines = 2,
-                                                        overflow = TextOverflow.Ellipsis
-                                                    )
-                                                }
-                                            }
-                                            Box {
-                                                IconButton(onClick = { annotationMenuExpandedFor = annotation }) {
-                                                    Icon(Icons.Default.MoreVert, contentDescription = readerString("desktop_annotation_options", "Annotation options"))
-                                                }
-                                                DropdownMenu(
-                                                    expanded = annotationMenuExpandedFor == annotation,
-                                                    onDismissRequest = { annotationMenuExpandedFor = null }
-                                                ) {
-                                                    DropdownMenuItem(
-                                                        text = {
-                                                            Text(
-                                                                if (annotation.note.isNullOrBlank() &&
-                                                                    annotation.kind != PdfAnnotationKind.TEXT
-                                                                ) {
-                                                                    readerString("menu_add_note", "Add note")
-                                                                } else {
-                                                                    readerString("action_edit", "Edit")
-                                                                }
-                                                            )
-                                                        },
-                                                        onClick = {
-                                                            annotationMenuExpandedFor = null
-                                                            onAnnotationSelected(annotation)
-                                                        }
-                                                    )
-                                                    DropdownMenuItem(
-                                                        text = { Text(readerString("action_delete", "Delete")) },
-                                                        onClick = {
-                                                            annotationMenuExpandedFor = null
-                                                            deleteAnnotationConfirmFor = annotation
-                                                        }
-                                                    )
-                                                }
-                                            }
-                                        }
-                                    }
-                                }
-                                items(sortedEmbeddedAnnotations, key = { "nav_embedded_${it.id}" }) { annotation ->
-                                    Surface(
-                                        color = if (annotation.id == selectedEmbeddedAnnotationId) {
-                                            MaterialTheme.colorScheme.primaryContainer
-                                        } else {
-                                            MaterialTheme.colorScheme.surfaceVariant
-                                        },
-                                        shape = RoundedCornerShape(6.dp),
-                                        modifier = Modifier.fillMaxWidth()
-                                    ) {
-                                        Row(verticalAlignment = Alignment.CenterVertically) {
-                                            Column(
-                                                modifier = Modifier
-                                                    .weight(1f)
-                                                    .clickable { onEmbeddedAnnotationOpened(annotation) }
-                                                    .padding(8.dp),
-                                                verticalArrangement = Arrangement.spacedBy(3.dp)
-                                            ) {
-                                                Text(
-                                                    annotation.author.ifBlank { readerString("desktop_pdf_comment", "PDF comment") },
-                                                    fontWeight = FontWeight.SemiBold,
-                                                    maxLines = 1,
-                                                    overflow = TextOverflow.Ellipsis
-                                                )
-                                                Text(
-                                                    readerString("pdf_page_short", "Page %1\$d", annotation.pageIndex + 1),
-                                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
-                                                    style = MaterialTheme.typography.bodySmall
-                                                )
-                                                annotation.contents.takeIf { it.isNotBlank() }?.let { contents ->
-                                                    Text(
-                                                        contents,
-                                                        color = MaterialTheme.colorScheme.onSurfaceVariant,
-                                                        style = MaterialTheme.typography.bodySmall,
-                                                        maxLines = 2,
-                                                        overflow = TextOverflow.Ellipsis
-                                                    )
-                                                }
-                                            }
-                                            Box {
-                                                IconButton(onClick = { embeddedAnnotationMenuExpandedFor = annotation }) {
-                                                    Icon(Icons.Default.MoreVert, contentDescription = readerString("desktop_comment_options", "Comment options"))
-                                                }
-                                                DropdownMenu(
-                                                    expanded = embeddedAnnotationMenuExpandedFor == annotation,
-                                                    onDismissRequest = { embeddedAnnotationMenuExpandedFor = null }
-                                                ) {
-                                                    DropdownMenuItem(
-                                                        text = { Text(readerString("desktop_open_comment", "Open comment")) },
-                                                        onClick = {
-                                                            embeddedAnnotationMenuExpandedFor = null
-                                                            onEmbeddedAnnotationSelected(annotation)
-                                                        }
-                                                    )
-                                                }
-                                            }
-                                        }
-                                    }
-                                }
+                        val highlightsListState = rememberLazyListState()
+                        var deleteHighlightConfirmFor by remember { mutableStateOf<SharedPdfAnnotation?>(null) }
+                        var filterWithNotesOnly by remember { mutableStateOf(false) }
+                        val filteredHighlights = remember(sortedHighlights, filterWithNotesOnly) {
+                            if (filterWithNotesOnly) {
+                                sortedHighlights.filter { !it.note.isNullOrBlank() }
+                            } else {
+                                sortedHighlights
                             }
-                            SharedReaderVerticalScrollbar(
-                                listState = annotationsListState,
-                                modifier = Modifier.align(Alignment.CenterEnd)
-                            )
                         }
-                        deleteAnnotationConfirmFor?.let { annotation ->
+
+                        Column(modifier = Modifier.fillMaxSize()) {
+                            Row(
+                                modifier = Modifier.fillMaxWidth().padding(horizontal = 16.dp, vertical = 8.dp),
+                                horizontalArrangement = Arrangement.spacedBy(8.dp)
+                            ) {
+                                FilterChip(
+                                    selected = !filterWithNotesOnly,
+                                    onClick = { filterWithNotesOnly = false },
+                                    label = { Text(readerString("read_status_all", "All")) }
+                                )
+                                FilterChip(
+                                    selected = filterWithNotesOnly,
+                                    onClick = { filterWithNotesOnly = true },
+                                    label = { Text(readerString("filter_with_notes", "With notes")) }
+                                )
+                            }
+                            Box(modifier = Modifier.fillMaxWidth().weight(1f)) {
+                                LazyColumn(
+                                    state = highlightsListState,
+                                    modifier = Modifier
+                                        .fillMaxSize()
+                                        .sharedAcceleratedLazyWheelScroll(highlightsListState)
+                                        .padding(end = 12.dp)
+                                ) {
+                                    items(filteredHighlights, key = { "nav_highlight_${it.id}" }) { highlight ->
+                                        ListItem(
+                                            headlineContent = {
+                                                Text(
+                                                    text = highlight.text.ifBlank {
+                                                        readerString(
+                                                            "msg_highlighted_section_default",
+                                                            "Highlighted section"
+                                                        )
+                                                    },
+                                                    maxLines = 2,
+                                                    overflow = TextOverflow.Ellipsis,
+                                                    fontWeight = FontWeight.SemiBold
+                                                )
+                                            },
+                                            supportingContent = {
+                                                Column {
+                                                    Row(verticalAlignment = Alignment.CenterVertically) {
+                                                        Box(
+                                                            modifier = Modifier
+                                                                .size(12.dp)
+                                                                .background(Color(highlight.colorArgb).copy(alpha = 1f), CircleShape)
+                                                        )
+                                                        Spacer(Modifier.width(8.dp))
+                                                        Text(
+                                                            readerString("pdf_page_short", "Page %1\$d", highlight.pageIndex + 1),
+                                                            style = MaterialTheme.typography.labelMedium,
+                                                            color = MaterialTheme.colorScheme.onSurfaceVariant
+                                                        )
+                                                    }
+                                                    highlight.note?.takeIf { it.isNotBlank() }?.let { note ->
+                                                        Spacer(Modifier.height(8.dp))
+                                                        Surface(
+                                                            shape = RoundedCornerShape(8.dp),
+                                                            color = MaterialTheme.colorScheme.surfaceVariant.copy(alpha = 0.5f),
+                                                            modifier = Modifier.fillMaxWidth()
+                                                        ) {
+                                                            Text(
+                                                                text = note,
+                                                                style = MaterialTheme.typography.bodySmall.copy(fontStyle = FontStyle.Italic),
+                                                                modifier = Modifier.padding(12.dp),
+                                                                color = MaterialTheme.colorScheme.onSurfaceVariant
+                                                            )
+                                                        }
+                                                    }
+                                                }
+                                            },
+                                            trailingContent = {
+                                                Box {
+                                                    var highlightMenuExpanded by remember(highlight.id) { mutableStateOf(false) }
+                                                    IconButton(onClick = { highlightMenuExpanded = true }) {
+                                                        Icon(
+                                                            Icons.Default.MoreVert,
+                                                            contentDescription = readerString("content_desc_options", "Options")
+                                                        )
+                                                    }
+                                                    DropdownMenu(
+                                                        expanded = highlightMenuExpanded,
+                                                        onDismissRequest = { highlightMenuExpanded = false }
+                                                    ) {
+                                                        DropdownMenuItem(
+                                                            text = {
+                                                                Text(
+                                                                    if (highlight.note.isNullOrBlank()) {
+                                                                        readerString("menu_add_note", "Add note")
+                                                                    } else {
+                                                                        readerString("menu_edit_note", "Edit note")
+                                                                    }
+                                                                )
+                                                            },
+                                                            onClick = {
+                                                                onAnnotationSelected(highlight)
+                                                                highlightMenuExpanded = false
+                                                            }
+                                                        )
+                                                        DropdownMenuItem(
+                                                            text = { Text(readerString("action_delete", "Delete")) },
+                                                            onClick = {
+                                                                deleteHighlightConfirmFor = highlight
+                                                                highlightMenuExpanded = false
+                                                            }
+                                                        )
+                                                    }
+                                                }
+                                            },
+                                            modifier = Modifier.clickable { onAnnotationOpened(highlight) }
+                                        )
+                                        HorizontalDivider()
+                                    }
+                                }
+                                SharedReaderVerticalScrollbar(
+                                    listState = highlightsListState,
+                                    modifier = Modifier.align(Alignment.CenterEnd)
+                                )
+                            }
+                        }
+
+                        deleteHighlightConfirmFor?.let { highlight ->
                             AlertDialog(
-                                onDismissRequest = { deleteAnnotationConfirmFor = null },
-                                title = { Text(readerString("desktop_delete_annotation_title", "Delete annotation?")) },
-                                text = { Text(readerString("desktop_delete_annotation_desc", "This removes the annotation from this PDF.")) },
+                                onDismissRequest = { deleteHighlightConfirmFor = null },
+                                title = { Text(readerString("dialog_delete_highlight", "Delete highlight?")) },
+                                text = { Text(readerString("dialog_delete_highlight_desc", "This removes the highlight from this PDF.")) },
                                 confirmButton = {
                                     TextButton(
                                         onClick = {
-                                            deleteAnnotationConfirmFor = null
-                                            onAnnotationDeleted(annotation)
+                                            onAnnotationDeleted(highlight)
+                                            deleteHighlightConfirmFor = null
                                         }
                                     ) {
-                                        Text(readerString("action_delete", "Delete"), color = MaterialTheme.colorScheme.error)
+                                        Text(readerString("action_delete", "Delete"))
                                     }
                                 },
                                 dismissButton = {
-                                    TextButton(onClick = { deleteAnnotationConfirmFor = null }) {
+                                    TextButton(onClick = { deleteHighlightConfirmFor = null }) {
                                         Text(readerString("action_cancel", "Cancel"))
                                     }
                                 }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfPage.kt

@@ -1,5 +1,7 @@
 package com.aryan.reader.desktop
 
+import androidx.compose.animation.Crossfade
+import androidx.compose.animation.core.tween
 import androidx.compose.foundation.background
 import androidx.compose.foundation.gestures.awaitEachGesture
 import androidx.compose.foundation.gestures.awaitFirstDown
@@ -67,6 +69,8 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.withContext
 
+private const val DesktopVerticalPdfPageTurnAnimationMillis = 140
+
 @Composable
 internal fun DesktopVerticalPdfPage(
     document: DesktopPdfDocument,
@@ -96,6 +100,8 @@ internal fun DesktopVerticalPdfPage(
     themeStyle: DesktopPdfThemeStyle,
     shouldRender: Boolean,
     zoomPreview: DesktopPdfZoomPreview?,
+    zoomPreviewAnchorPageRootOffset: Offset? = null,
+    zoomPreviewScrollBounds: DesktopPdfZoomScrollBounds? = null,
     zoomViewportRootOffset: Offset,
     showPageNumberOverlay: Boolean = true,
     onSelectPage: (Int) -> Unit,
@@ -116,13 +122,16 @@ internal fun DesktopVerticalPdfPage(
     onTextDraftChanged: (String, IntSize) -> Unit,
     onTextDraftBoundsChanged: (PdfPageBounds) -> Unit,
     onPan: (Offset) -> Unit,
+    onPageSizeChanged: (Int, IntSize) -> Unit = { _, _ -> },
     onPagePositioned: (Int, Offset) -> Unit
 ) {
     val documentHandleId = document.handleId
     val density = LocalDensity.current
-    var renderedPage by remember(documentHandleId, pageIndex) { mutableStateOf<DesktopPdfPageRender?>(null) }
-    var renderError by remember(documentHandleId, pageIndex) { mutableStateOf<String?>(null) }
-    var isRendering by remember(documentHandleId, pageIndex) { mutableStateOf(true) }
+    var renderedPage by remember(documentHandleId) { mutableStateOf<DesktopPdfPageRender?>(null) }
+    var renderedPageIndex by remember(documentHandleId) { mutableStateOf<Int?>(null) }
+    var renderedPageScale by remember(documentHandleId) { mutableStateOf<Float?>(null) }
+    var renderError by remember(documentHandleId) { mutableStateOf<String?>(null) }
+    var isRendering by remember(documentHandleId) { mutableStateOf(true) }
     var pageCanvasSize by remember(documentHandleId, pageIndex) { mutableStateOf(IntSize.Zero) }
     var pageRootOffset by remember(documentHandleId, pageIndex) { mutableStateOf(Offset.Zero) }
     var selectionStartIndex by remember(documentHandleId, pageIndex) { mutableStateOf<Int?>(null) }
@@ -156,34 +165,73 @@ internal fun DesktopVerticalPdfPage(
 
     LaunchedEffect(documentHandleId, pageIndex, scale, shouldRender) {
         if (!shouldRender) {
+            logPdfZoomSettle {
+                "item_render_skip page=${pageIndex + 1} reason=outside_window scale=${scale.formatLogFloat()}"
+            }
             renderedPage = null
+            renderedPageIndex = null
+            renderedPageScale = null
             renderError = null
             isRendering = false
             clearInteractionState()
             return@LaunchedEffect
         }
-        val hasPageRender = renderedPage != null
+        val hasPageRender = renderedPage != null && desktopPdfRenderBelongsToPage(renderedPageIndex, pageIndex)
+        logPdfZoomSettle {
+            "item_render_effect page=${pageIndex + 1} scale=${scale.formatLogFloat()} shouldRender=$shouldRender " +
+                "hasRender=$hasPageRender renderedPage=${renderedPageIndex?.plus(1) ?: "none"} " +
+                "renderScale=${renderedPageScale?.formatLogFloat() ?: "none"}"
+        }
         if (!hasPageRender) {
+            renderedPage = null
+            renderedPageIndex = null
+            renderedPageScale = null
             isRendering = true
         }
         renderError = null
         val pageSize = document.pageSizes.getOrNull(pageIndex)
         if (pageSize == null) {
             renderedPage = null
+            renderedPageIndex = null
+            renderedPageScale = null
             renderError = failedRenderMessage
             isRendering = false
             return@LaunchedEffect
         }
+        val safeScale = zoomSpec.safeRenderScale(pageSize.width, pageSize.height, scale)
+        if (hasPageRender && !desktopPdfRenderScaleNeedsUpgrade(renderedPageScale, safeScale)) {
+            logPdfZoomSettle {
+                "item_render_skip page=${pageIndex + 1} reason=no_scale_upgrade " +
+                    "safeScale=${safeScale.formatLogFloat()} existingScale=${renderedPageScale?.formatLogFloat() ?: "none"}"
+            }
+            isRendering = false
+            return@LaunchedEffect
+        }
+        logPdfZoomSettle {
+            "item_render_scheduled page=${pageIndex + 1} safeScale=${safeScale.formatLogFloat()} " +
+                "delayMs=${if (hasPageRender) DesktopPdfZoomRenderDebounceMillis else 45L} hasRender=$hasPageRender"
+        }
         delay(if (hasPageRender) DesktopPdfZoomRenderDebounceMillis else 45L)
         isRendering = true
-        val safeScale = zoomSpec.safeRenderScale(pageSize.width, pageSize.height, scale)
+        val renderStartedAt = System.currentTimeMillis()
         val result = withContext(Dispatchers.IO) {
             runCatching { DesktopPdfium.renderPage(document, pageIndex, safeScale) }
         }
-        result.getOrNull()?.let { renderedPage = it }
+        val renderElapsedMs = System.currentTimeMillis() - renderStartedAt
+        result.getOrNull()?.let {
+            renderedPage = it
+            renderedPageIndex = pageIndex
+            renderedPageScale = safeScale
+        }
+        val renderedCurrentPage = renderedPage != null && desktopPdfRenderBelongsToPage(renderedPageIndex, pageIndex)
         renderError = result.exceptionOrNull()?.message
-            ?: if (renderedPage == null) failedRenderMessage else null
+            ?: if (!renderedCurrentPage && renderedPage == null) failedRenderMessage else null
         isRendering = false
+        logPdfZoomSettle {
+            "item_render_end page=${pageIndex + 1} safeScale=${safeScale.formatLogFloat()} " +
+                "elapsedMs=$renderElapsedMs success=${result.isSuccess} bitmap=${renderedPage?.width ?: 0}x${renderedPage?.height ?: 0} " +
+                "canvas=${pageCanvasSize.formatLogSize()} root=${pageRootOffset.formatLogOffset()}"
+        }
     }
 
     LaunchedEffect(isTextSelectionMode) {
@@ -205,6 +253,8 @@ internal fun DesktopVerticalPdfPage(
         verticalArrangement = Arrangement.spacedBy(6.dp)
     ) {
         val pageSize = document.pageSizes.getOrNull(pageIndex)
+        val displayPageIndex = renderedPageIndex ?: pageIndex
+        val displayPageIsCurrent = displayPageIndex == pageIndex
         val placeholderScale = zoomSpec.clamp(scale)
         val placeholderWidthDp = with(density) { ((pageSize?.width ?: 612f) * placeholderScale).toDp() }
         val placeholderHeightDp = with(density) { ((pageSize?.height ?: 792f) * placeholderScale).toDp() }
@@ -224,24 +274,60 @@ internal fun DesktopVerticalPdfPage(
                 .size(placeholderWidthDp, placeholderHeightDp)
                 .onGloballyPositioned { coordinates ->
                     val rootOffset = coordinates.positionInRoot()
+                    if (rootOffset != pageRootOffset) {
+                        logPdfZoomSettle {
+                            "item_layout page=${pageIndex + 1} prevRoot=${pageRootOffset.formatLogOffset()} " +
+                                "nextRoot=${rootOffset.formatLogOffset()} scale=${scale.formatLogFloat()} " +
+                                "preview=${zoomPreview != null} canvas=${pageCanvasSize.formatLogSize()}"
+                        }
+                    }
                     pageRootOffset = rootOffset
                     onPagePositioned(pageIndex, rootOffset)
                 }
-                .onSizeChanged { pageCanvasSize = it }
+                .onSizeChanged { size ->
+                    if (pageCanvasSize != size) {
+                        logPdfZoomSettle {
+                            "item_size page=${pageIndex + 1} prev=${pageCanvasSize.formatLogSize()} " +
+                                "next=${size.formatLogSize()} scale=${scale.formatLogFloat()} " +
+                                "preview=${zoomPreview != null} renderScale=${pageRenderScale.formatLogFloat()}"
+                        }
+                    }
+                    pageCanvasSize = size
+                    onPageSizeChanged(pageIndex, size)
+                }
                 .desktopPdfDocumentZoomPreviewLayer(
                     preview = zoomPreview,
                     currentZoom = scale,
                     viewportRootOffset = zoomViewportRootOffset,
-                    pageRootOffset = pageRootOffset
+                    pageRootOffset = pageRootOffset,
+                    anchorPageRootOffset = zoomPreviewAnchorPageRootOffset,
+                    scrollBounds = zoomPreviewScrollBounds
                 )
                 .background(themeStyle.pageBackgroundColor, RoundedCornerShape(2.dp))
-                .pointerInput(pageIndex, pageCanvasSize, isTextSelectionMode, selectedTool, isRichTextMode) {
-                    if (isRichTextMode) return@pointerInput
+                .pointerInput(
+                    pageIndex,
+                    displayPageIsCurrent,
+                    pageCanvasSize,
+                    isTextSelectionMode,
+                    selectedTool,
+                    isRichTextMode
+                ) {
+                    if (!displayPageIsCurrent || isRichTextMode) return@pointerInput
                     awaitPointerEventScope {
                         while (true) {
                             val event = awaitPointerEvent()
                             val point = event.changes.firstOrNull()?.position ?: continue
                             if (event.type == PointerEventType.Press && event.buttons.isPrimaryPressed) {
+                                if (isTextSelectionMode) {
+                                    logPdfChromeTap {
+                                        "page_press source=vertical_page page=${pageIndex + 1} " +
+                                            "x=${point.x.formatLogFloat()} y=${point.y.formatLogFloat()} " +
+                                            "consumedBefore=${event.changes.any { it.isConsumed }} " +
+                                            "selectionActive=${currentTextSelection != null} " +
+                                            "selectionMenuOpen=${selectionMenuOffset != null} " +
+                                            "selectedTool=$selectedTool richText=$isRichTextMode"
+                                    }
+                                }
                                 val highlightHit = if (selectedTool != PdfInkTool.TEXT && selectedTool != PdfInkTool.ERASER) {
                                     currentAnnotations.asReversed().firstOrNull {
                                         it.isDesktopTextSelectionHighlight &&
@@ -252,6 +338,10 @@ internal fun DesktopVerticalPdfPage(
                                     null
                                 }
                                 if (highlightHit != null) {
+                                    logPdfChromeTap {
+                                        "page_press_consume source=vertical_page page=${pageIndex + 1} " +
+                                            "reason=text_selection_highlight annotation=${highlightHit.id}"
+                                    }
                                     onSelectPage(pageIndex)
                                     onAnnotationSelected(highlightHit)
                                     clearInteractionState()
@@ -261,6 +351,10 @@ internal fun DesktopVerticalPdfPage(
                                 if (selectedTool != PdfInkTool.TEXT) {
                                     val linkTarget = document.linkAt(pageIndex, point, pageCanvasSize)
                                     if (linkTarget != null) {
+                                        logPdfChromeTap {
+                                            "page_press_consume source=vertical_page page=${pageIndex + 1} " +
+                                                "reason=link target=${linkTarget.formatLogTarget()}"
+                                        }
                                         logPdfLink(
                                             "tap_hit mode=vertical page=${pageIndex + 1} " +
                                                 "x=${point.x.formatLogFloat()} y=${point.y.formatLogFloat()} " +
@@ -277,6 +371,10 @@ internal fun DesktopVerticalPdfPage(
                                     it.sharedPdfEmbeddedHitTest(point, pageCanvasSize)
                                 }
                                 if (embeddedHit != null) {
+                                    logPdfChromeTap {
+                                        "page_press_consume source=vertical_page page=${pageIndex + 1} " +
+                                            "reason=embedded_annotation annotation=${embeddedHit.id}"
+                                    }
                                     onSelectPage(pageIndex)
                                     onEmbeddedAnnotationSelected(embeddedHit)
                                     clearInteractionState()
@@ -285,7 +383,16 @@ internal fun DesktopVerticalPdfPage(
                                     currentTextSelection != null &&
                                     selectionMenuOffset == null
                                 ) {
+                                    logPdfChromeTap {
+                                        "page_press_passthrough source=vertical_page page=${pageIndex + 1} " +
+                                            "action=clear_selection consumed=false"
+                                    }
                                     clearSelection()
+                                } else if (isTextSelectionMode) {
+                                    logPdfChromeTap {
+                                        "page_press_passthrough source=vertical_page page=${pageIndex + 1} " +
+                                            "action=none consumed=false"
+                                    }
                                 }
                             } else if (event.type == PointerEventType.Press && event.buttons.isSecondaryPressed) {
                                 val selection = currentTextSelection
@@ -304,33 +411,41 @@ internal fun DesktopVerticalPdfPage(
                         }
                     }
                 }
-                .pointerInput(pageIndex, pageCanvasSize, isTextSelectionMode, isRichTextMode) {
-                    if (isRichTextMode || !isTextSelectionMode) return@pointerInput
-                    detectTapGestures(
-                        onLongPress = { point ->
-                            val selection = document.wordSelectionAt(pageIndex, point, pageCanvasSize)
-                            if (selection != null) {
-                                onSelectPage(pageIndex)
-                                selectionStartIndex = null
-                                selectionEndIndex = null
-                                selectionStartHit = null
-                                selectionEndHit = null
-                                activeSelectionHandle = null
-                                textSelection = selection
-                                selectionMenuOffset = selection.menuAnchor(pageCanvasSize, point)
-                                logPdfSelection(
-                                    "long_press page=${pageIndex + 1} " +
-                                        "x=${point.x.formatLogFloat()} y=${point.y.formatLogFloat()} " +
-                                        "range=${selection.startIndex}..${selection.endIndex} " +
-                                        "chars=${selection.text.length} " +
-                                        "text=\"${selection.text.logPreview()}\""
-                                )
-                            }
+                .pointerInput(pageIndex, displayPageIsCurrent, pageCanvasSize, isTextSelectionMode, isRichTextMode) {
+                    if (!displayPageIsCurrent || isRichTextMode || !isTextSelectionMode) return@pointerInput
+                    detectDesktopPdfTextSelectionLongPress(
+                        source = "vertical_page",
+                        pageIndex = pageIndex
+                    ) { point ->
+                        val selection = document.wordSelectionAt(pageIndex, point, pageCanvasSize)
+                        logPdfChromeTap {
+                            "long_press_selection source=vertical_page page=${pageIndex + 1} " +
+                                "selectionFound=${selection != null} " +
+                                "x=${point.x.formatLogFloat()} y=${point.y.formatLogFloat()}"
                         }
-                    )
+                        if (selection != null) {
+                            onSelectPage(pageIndex)
+                            selectionStartIndex = null
+                            selectionEndIndex = null
+                            selectionStartHit = null
+                            selectionEndHit = null
+                            activeSelectionHandle = null
+                            textSelection = selection
+                            selectionMenuOffset = selection.menuAnchor(pageCanvasSize, point)
+                            logPdfSelection(
+                                "long_press page=${pageIndex + 1} " +
+                                    "x=${point.x.formatLogFloat()} y=${point.y.formatLogFloat()} " +
+                                    "range=${selection.startIndex}..${selection.endIndex} " +
+                                    "chars=${selection.text.length} " +
+                                    "text=\"${selection.text.logPreview()}\""
+                            )
+                        }
+                    }
                 }
-                .pointerInput(pageIndex, selectedTool, isTextSelectionMode, isRichTextMode) {
-                    if (isRichTextMode || isTextSelectionMode || selectedTool != PdfInkTool.NONE) return@pointerInput
+                .pointerInput(pageIndex, displayPageIsCurrent, selectedTool, isTextSelectionMode, isRichTextMode) {
+                    if (!displayPageIsCurrent || isRichTextMode || isTextSelectionMode || selectedTool != PdfInkTool.NONE) {
+                        return@pointerInput
+                    }
                     awaitEachGesture {
                         val down = awaitFirstDown(requireUnconsumed = false)
                         if (!currentEvent.buttons.isPrimaryPressed) return@awaitEachGesture
@@ -371,9 +486,10 @@ internal fun DesktopVerticalPdfPage(
                     isRichTextMode,
                     pageCanvasSize,
                     renderedPageWidth,
-                    renderedPageHeight
+                    renderedPageHeight,
+                    displayPageIsCurrent
                 ) {
-                    if (renderedPageWidth > 0 && renderedPageHeight > 0) {
+                    if (displayPageIsCurrent && renderedPageWidth > 0 && renderedPageHeight > 0) {
                         if (isRichTextMode) return@pointerInput
                         if (isTextSelectionMode) {
                             var latestSelectionDragPoint: Offset? = null
@@ -638,8 +754,21 @@ internal fun DesktopVerticalPdfPage(
                         color = MaterialTheme.colorScheme.onSurfaceVariant
                     )
                 }
-                renderedPage != null -> {
+                renderError != null && renderedPageIndex != pageIndex -> Text(
+                    renderError ?: readerString("desktop_failed_render_page", "Failed to render page."),
+                    color = MaterialTheme.colorScheme.error
+                )
+                renderedPage != null && desktopPdfRenderBelongsToPage(renderedPageIndex, pageIndex) -> {
+                    val currentRenderedPageIndex = renderedPageIndex!!
+                    Crossfade(
+                        targetState = currentRenderedPageIndex,
+                        animationSpec = tween(DesktopVerticalPdfPageTurnAnimationMillis),
+                        label = "DesktopVerticalPdfPage"
+                    ) { pageIndex ->
                     val pageRender = renderedPage!!
+                    val pageEmbeddedAnnotations = remember(document.embeddedAnnotations, pageIndex) {
+                        document.embeddedAnnotations.filter { it.pageIndex == pageIndex }
+                    }
                     val pageAnnotations = remember(annotations, pageIndex, pageCanvasSize) {
                         annotations
                             .filter { it.pageIndex == pageIndex }
@@ -806,6 +935,10 @@ internal fun DesktopVerticalPdfPage(
                                 .matchParentSize()
                                 .pointerInput(pageIndex, selectionMenuOffset) {
                                     detectTapGestures {
+                                        logPdfChromeTap {
+                                            "selection_menu_scrim_tap source=vertical_page page=${pageIndex + 1} " +
+                                                "consumedByScrim=true"
+                                        }
                                         clearSelection()
                                     }
                                 }
@@ -842,6 +975,7 @@ internal fun DesktopVerticalPdfPage(
                         showSearch = externalLookupAvailable,
                         onClear = ::clearSelection
                     )
+                    }
                 }
                 isRendering -> CircularProgressIndicator()
                 renderError != null -> Text(

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfPageInteractions.kt

@@ -1,6 +1,11 @@
 package com.aryan.reader.desktop
 
+import androidx.compose.foundation.gestures.awaitEachGesture
+import androidx.compose.foundation.gestures.awaitFirstDown
 import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.input.pointer.PointerInputScope
+import androidx.compose.ui.input.pointer.changedToUp
+import androidx.compose.ui.input.pointer.isSecondaryPressed
 import androidx.compose.ui.unit.IntSize
 import com.aryan.reader.shared.pdf.PdfAnnotationKind
 import com.aryan.reader.shared.pdf.PdfInkTool
@@ -9,11 +14,17 @@ import com.aryan.reader.shared.pdf.PdfPageBounds
 import com.aryan.reader.shared.pdf.PdfPagePoint
 import com.aryan.reader.shared.pdf.PdfSelectionGeometry
 import com.aryan.reader.shared.pdf.PdfTextCharBounds
+import com.aryan.reader.shared.pdf.PdfZoomSpec
 import com.aryan.reader.shared.pdf.SharedPdfAnnotation
 import com.aryan.reader.shared.pdf.SharedPdfInkRenderer
+import com.aryan.reader.shared.pdf.SharedPdfReaderAction
+import com.aryan.reader.shared.pdf.SharedPdfReaderState
 import com.aryan.reader.shared.pdf.SharedPdfTextDraft
+import com.aryan.reader.shared.pdf.reduce
 import com.aryan.reader.shared.ui.sharedPdfHitTest
 import com.aryan.reader.shared.ui.toSharedPdfPoint
+import kotlinx.coroutines.TimeoutCancellationException
+import kotlinx.coroutines.withTimeout
 
 internal val PdfInkTool.isDesktopHighlighter: Boolean
     get() = this == PdfInkTool.HIGHLIGHTER || this == PdfInkTool.HIGHLIGHTER_ROUND
@@ -24,6 +35,24 @@ internal val SharedPdfAnnotation.isDesktopTextSelectionHighlight: Boolean
         rangeStartIndex != null &&
         rangeEndIndex != null
 
+internal fun SharedPdfReaderState.withDesktopPdfTextSelectionHighlightAdded(
+    annotation: SharedPdfAnnotation,
+    zoomSpec: PdfZoomSpec = PdfZoomSpec()
+): SharedPdfReaderState {
+    val next = reduce(SharedPdfReaderAction.AnnotationAdded(annotation), zoomSpec)
+    return if (annotation.isDesktopTextSelectionHighlight) {
+        next.reduce(SharedPdfReaderAction.AnnotationSelected(null), zoomSpec)
+    } else {
+        next
+    }
+}
+
+internal fun SharedPdfReaderState.withDesktopPdfTextHighlightSheetDismissed(
+    zoomSpec: PdfZoomSpec = PdfZoomSpec()
+): SharedPdfReaderState {
+    return reduce(SharedPdfReaderAction.AnnotationSelected(null), zoomSpec)
+}
+
 internal fun List<PdfPagePoint>.withDesktopPdfDragPoint(
     point: Offset,
     canvasSize: IntSize,
@@ -46,6 +75,95 @@ internal fun List<PdfPagePoint>.withDesktopPdfDragPoint(
     return this + nextPoint
 }
 
+internal suspend fun PointerInputScope.detectDesktopPdfTextSelectionLongPress(
+    source: String,
+    pageIndex: Int,
+    onLongPress: (Offset) -> Unit
+) {
+    awaitEachGesture {
+        val down = awaitFirstDown(requireUnconsumed = false)
+        val secondaryDown = currentEvent.buttons.isSecondaryPressed
+        logPdfChromeTap {
+            "long_press_down source=$source page=${pageIndex + 1} " +
+                "x=${down.position.x.formatLogFloat()} y=${down.position.y.formatLogFloat()} " +
+                "downConsumed=${down.isConsumed} secondary=$secondaryDown"
+        }
+        if (down.isConsumed || secondaryDown) {
+            logPdfChromeTap {
+                "long_press_skip source=$source page=${pageIndex + 1} " +
+                    "reason=${if (down.isConsumed) "down_consumed" else "secondary_button"}"
+            }
+            return@awaitEachGesture
+        }
+        val pointerId = down.id
+        val start = down.position
+        var latestPosition = start
+        var canceledBeforeLongPress = false
+        var longPressReached = false
+        var cancelReason = ""
+
+        try {
+            withTimeout(viewConfiguration.longPressTimeoutMillis) {
+                while (true) {
+                    val event = awaitPointerEvent()
+                    if (event.buttons.isSecondaryPressed) {
+                        canceledBeforeLongPress = true
+                        cancelReason = "secondary_button"
+                        return@withTimeout
+                    }
+                    val change = event.changes.firstOrNull { it.id == pointerId }
+                    if (change == null) {
+                        canceledBeforeLongPress = true
+                        cancelReason = "pointer_lost"
+                        return@withTimeout
+                    }
+                    latestPosition = change.position
+                    val distance = (latestPosition - start).getDistance()
+                    when {
+                        change.isConsumed -> {
+                            canceledBeforeLongPress = true
+                            cancelReason = "change_consumed"
+                            return@withTimeout
+                        }
+                        change.changedToUp() || !change.pressed -> {
+                            canceledBeforeLongPress = true
+                            cancelReason = "up_before_long_press"
+                            return@withTimeout
+                        }
+                        distance > viewConfiguration.touchSlop -> {
+                            canceledBeforeLongPress = true
+                            cancelReason = "moved distance=${distance.formatLogFloat()}"
+                            return@withTimeout
+                        }
+                    }
+                }
+            }
+        } catch (_: TimeoutCancellationException) {
+            longPressReached = !canceledBeforeLongPress
+        }
+
+        if (!longPressReached) {
+            logPdfChromeTap {
+                "long_press_cancel source=$source page=${pageIndex + 1} " +
+                    "reason=${cancelReason.ifBlank { "unknown" }} " +
+                    "x=${latestPosition.x.formatLogFloat()} y=${latestPosition.y.formatLogFloat()}"
+            }
+            return@awaitEachGesture
+        }
+        logPdfChromeTap {
+            "long_press_reached source=$source page=${pageIndex + 1} " +
+                "x=${latestPosition.x.formatLogFloat()} y=${latestPosition.y.formatLogFloat()}"
+        }
+        onLongPress(latestPosition)
+        while (true) {
+            val event = awaitPointerEvent()
+            val change = event.changes.firstOrNull { it.id == pointerId } ?: return@awaitEachGesture
+            change.consume()
+            if (change.changedToUp() || !change.pressed) return@awaitEachGesture
+        }
+    }
+}
+
 internal data class DesktopPdfCharHit(
     val index: Int,
     val source: String,
@@ -318,7 +436,7 @@ private fun DesktopPdfTextChar.toPdfTextCharBounds(): PdfTextCharBounds {
 }
 
 internal const val DesktopPdfSelectionPreviewThrottleMillis = 32L
-internal const val DesktopPdfZoomCommitDebounceMillis = 180L
+internal const val DesktopPdfZoomCommitDebounceMillis = 260L
 internal const val DesktopPdfZoomRenderDebounceMillis = 300L
 internal const val DesktopPdfViewportPersistDebounceMillis = 300L
 internal const val DesktopPdfPaginationPrefetchDelayMillis = 450L

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfScrubbing.kt

@@ -0,0 +1,28 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.PdfDisplayMode
+import com.aryan.reader.shared.pdf.PdfSpreadLayout
+import com.aryan.reader.shared.reader.ReaderSettings
+import kotlin.math.roundToInt
+
+internal fun desktopPdfPageScrubTarget(
+    value: Float,
+    pageCount: Int,
+    displayMode: PdfDisplayMode,
+    settings: ReaderSettings
+): Int {
+    val clampedPage = value.roundToInt().coerceIn(0, (pageCount - 1).coerceAtLeast(0))
+    return if (displayMode == PdfDisplayMode.PAGINATION) {
+        PdfSpreadLayout.normalizePageIndex(clampedPage, pageCount, settings)
+    } else {
+        clampedPage
+    }
+}
+
+internal fun desktopPdfPageScrubCommitTarget(
+    previewPage: Int?,
+    currentPage: Int,
+    pageCount: Int
+): Int {
+    return (previewPage ?: currentPage).coerceIn(0, (pageCount - 1).coerceAtLeast(0))
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfSelectionUi.kt

@@ -53,7 +53,6 @@ import androidx.compose.ui.unit.IntOffset
 import androidx.compose.ui.unit.IntSize
 import androidx.compose.ui.unit.dp
 import com.aryan.reader.shared.pdf.PdfPageBounds
-import com.aryan.reader.shared.pdf.SharedPdfAndroidHighlightColors
 import com.aryan.reader.shared.pdf.SharedPdfHighlighterPalette
 import com.aryan.reader.shared.ui.SharedHsvColorPickerDialog
 import com.aryan.reader.shared.ui.SharedSelectionMenuRect
@@ -292,11 +291,15 @@ internal fun PdfSelectionMenu(
     val anchor = menuOffset ?: return
     val selectionBounds = selection.canvasBounds(canvasSize)
     val paletteColors = remember(highlighterPalette) {
-        SharedPdfAndroidHighlightColors.palette
+        SharedPdfHighlighterPalette(highlighterPalette).sanitized().colors
     }
+    val density = LocalDensity.current
     var editingHighlighterSlot by remember(selection.startIndex, selection.endIndex, paletteColors) {
         mutableStateOf<Int?>(null)
     }
+    var editingHighlighterDraftColors by remember(selection.startIndex, selection.endIndex, paletteColors) {
+        mutableStateOf<List<Int>>(emptyList())
+    }
     val actions = buildList {
         add(PdfSelectionMenuAction(readerString("action_copy", "Copy"), DesktopPdfSelectionMenuIcons.Copy, onCopy))
         if (showDefine) add(PdfSelectionMenuAction(readerString("action_define", "Define"), DesktopPdfSelectionMenuIcons.Dictionary, onDefine))
@@ -304,13 +307,38 @@ internal fun PdfSelectionMenu(
         if (showSearch) add(PdfSelectionMenuAction(readerString("action_search", "Search"), DesktopPdfSelectionMenuIcons.Search, onSearch))
         add(PdfSelectionMenuAction(readerString("action_clear", "Clear"), Icons.Default.Close, onClear, isDestructive = true))
     }
-    val estimatedHeight = PdfSelectionMenuPaletteHeightPx +
-        (((actions.size + 2) / 3).coerceAtLeast(1) * PdfSelectionMenuActionRowHeightPx)
+
+    fun highlighterDraftColors(): List<Int> {
+        return editingHighlighterDraftColors.ifEmpty { paletteColors }
+    }
+
+    fun updateHighlighterDraft(slotIndex: Int, color: Color): List<Int> {
+        val nextColors = highlighterDraftColors().toMutableList()
+        if (slotIndex in nextColors.indices) {
+            nextColors[slotIndex] = color.copy(alpha = SharedPdfHighlighterPalette.DefaultAlpha / 255f).toArgb()
+            editingHighlighterDraftColors = nextColors
+        }
+        return nextColors
+    }
+
+    fun openHighlighterEditor(slotIndex: Int) {
+        if (editingHighlighterSlot == null) {
+            editingHighlighterDraftColors = paletteColors
+        }
+        editingHighlighterSlot = slotIndex
+    }
+
+    val actionRowCount = ((actions.size + 2) / 3).coerceAtLeast(1)
+    val popupWidthPx = with(density) { PdfSelectionMenuWidth.toPx() }
+    val estimatedHeightPx = with(density) {
+        PdfSelectionMenuPaletteHeight.toPx() +
+            (actionRowCount * PdfSelectionMenuActionRowHeight.toPx())
+    }
     val placement = sharedSelectionMenuPlacement(
         viewport = SharedSelectionMenuViewport(canvasSize.width, canvasSize.height),
         popup = SharedSelectionMenuSize(
-            width = PdfSelectionMenuWidthPx.roundToInt(),
-            height = estimatedHeight.roundToInt()
+            width = popupWidthPx.roundToInt(),
+            height = estimatedHeightPx.roundToInt()
         ),
         selection = if (selectionBounds != null) {
             SharedSelectionMenuRect(
@@ -327,8 +355,8 @@ internal fun PdfSelectionMenu(
                 bottom = anchor.y
             )
         },
-        marginPx = PdfSelectionMenuMarginPx,
-        gapPx = PdfSelectionMenuAnchorGapPx
+        marginPx = with(density) { PdfSelectionMenuMargin.toPx() },
+        gapPx = with(density) { PdfSelectionMenuAnchorGap.toPx() }
     )
     Box(Modifier.fillMaxSize(), contentAlignment = Alignment.TopStart) {
         Surface(
@@ -385,7 +413,7 @@ internal fun PdfSelectionMenu(
                                 )
                             )
                             .border(1.dp, MaterialTheme.colorScheme.outline.copy(alpha = 0.32f), RoundedCornerShape(16.dp))
-                            .clickable { editingHighlighterSlot = 0 }
+                            .clickable { openHighlighterEditor(0) }
                     )
                 }
                 HorizontalDivider()
@@ -436,20 +464,27 @@ internal fun PdfSelectionMenu(
         }
     }
     editingHighlighterSlot?.let { requestedSlot ->
-        val slot = requestedSlot.coerceIn(0, paletteColors.lastIndex)
-        val initialColor = Color(paletteColors[slot]).copy(alpha = 1f)
+        val draftColors = highlighterDraftColors()
+        val safeDraftColors = draftColors.ifEmpty { SharedPdfHighlighterPalette.defaultColors }
+        val slot = requestedSlot.coerceIn(0, safeDraftColors.lastIndex)
+        val initialColor = remember(slot) { Color(safeDraftColors[slot]).copy(alpha = 1f) }
         SharedHsvColorPickerDialog(
             initialColor = initialColor,
             title = readerString("desktop_highlight_color_format", "Highlight color %1\$d", slot + 1),
             onDismiss = { editingHighlighterSlot = null },
             onSave = { color ->
+                val nextColors = updateHighlighterDraft(slot, color)
                 onHighlighterPaletteChange(
-                    SharedPdfHighlighterPalette(paletteColors).withColorAt(
-                        slotIndex = slot,
-                        colorArgb = color.copy(alpha = SharedPdfHighlighterPalette.DefaultAlpha / 255f).toArgb()
-                    )
+                    SharedPdfHighlighterPalette(nextColors).sanitized()
                 )
                 editingHighlighterSlot = null
+            },
+            resetColor = Color(SharedPdfHighlighterPalette.defaultColors.getOrElse(slot) {
+                SharedPdfHighlighterPalette.defaultColors.first()
+            }).copy(alpha = 1f),
+            stateKey = slot,
+            onLiveColorChange = { color ->
+                updateHighlighterDraft(slot, color)
             }
         ) { liveColor ->
             Column(verticalArrangement = Arrangement.spacedBy(12.dp)) {
@@ -458,7 +493,7 @@ internal fun PdfSelectionMenu(
                     horizontalArrangement = Arrangement.spacedBy(10.dp),
                     verticalAlignment = Alignment.CenterVertically
                 ) {
-                    paletteColors.forEachIndexed { index, argb ->
+                    highlighterDraftColors().forEachIndexed { index, argb ->
                         val color = if (index == slot) liveColor else Color(argb).copy(alpha = 1f)
                         Box(
                             modifier = Modifier
@@ -467,10 +502,14 @@ internal fun PdfSelectionMenu(
                                 .background(color)
                                 .border(
                                     width = if (index == slot) 3.dp else 1.dp,
-                                    color = if (index == slot) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.outline.copy(alpha = 0.35f),
+                                    color = if (index == slot) {
+                                        MaterialTheme.colorScheme.primary
+                                    } else {
+                                        MaterialTheme.colorScheme.outline.copy(alpha = 0.35f)
+                                    },
                                     shape = RoundedCornerShape(21.dp)
                                 )
-                                .clickable { editingHighlighterSlot = index },
+                                .clickable { openHighlighterEditor(index) },
                             contentAlignment = Alignment.Center
                         ) {
                             Text(
@@ -494,11 +533,11 @@ private data class PdfSelectionMenuAction(
     val isDestructive: Boolean = false
 )
 
-private const val PdfSelectionMenuWidthPx = 220f
-private const val PdfSelectionMenuPaletteHeightPx = 54f
-private const val PdfSelectionMenuActionRowHeightPx = 66f
-private const val PdfSelectionMenuAnchorGapPx = 16f
-private const val PdfSelectionMenuMarginPx = 6f
+private val PdfSelectionMenuWidth = 220.dp
+private val PdfSelectionMenuPaletteHeight = 54.dp
+private val PdfSelectionMenuActionRowHeight = 66.dp
+private val PdfSelectionMenuAnchorGap = 16.dp
+private val PdfSelectionMenuMargin = 6.dp
 private const val DesktopPdfSelectionHandleTouchWidthPx = 44f
 private const val DesktopPdfSelectionHandleTouchTopPx = 8f
 private const val DesktopPdfSelectionHandleTouchBottomPx = 40f

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfSidecarEffects.kt

@@ -36,18 +36,40 @@ internal fun DesktopPdfAnnotationSidecarEffect(
             emptyList()
         }
         onAnnotationsLoaded(loadedAnnotations)
+        logDesktopCloudAnnotations {
+            "desktop.local.load_annotations document=$documentHandleId count=${loadedAnnotations.size} " +
+                "exists=${annotationFile.exists()} bytes=${annotationFile.length()} ts=${annotationFile.lastModifiedIfFileForCloudLog()}"
+        }
         onAnnotationsLoadedChange(true)
     }
 
     LaunchedEffect(documentHandleId, annotations, annotationsLoaded) {
         if (!annotationsLoaded) return@LaunchedEffect
-        withContext(Dispatchers.IO) {
+        val changed = withContext(Dispatchers.IO) {
             runCatching {
-                annotationFile.parentFile?.mkdirs()
-                annotationFile.writeText(SharedPdfAnnotationSerializer.encode(annotations))
-            }
+                val nextJson = SharedPdfAnnotationSerializer.encode(annotations)
+                when {
+                    annotations.isEmpty() && annotationFile.isFile -> {
+                        annotationFile.delete()
+                    }
+                    annotations.isEmpty() -> false
+                    annotationFile.isFile && annotationFile.readText() == nextJson -> false
+                    else -> {
+                        annotationFile.parentFile?.mkdirs()
+                        annotationFile.writeText(nextJson)
+                        true
+                    }
+                }
+            }.getOrDefault(false)
+        }
+        if (changed) {
+            logDesktopCloudAnnotations {
+                "desktop.local.save_annotations document=$documentHandleId count=${annotations.size} " +
+                    "bytes=${annotationFile.length()} ts=${annotationFile.lastModifiedIfFileForCloudLog()} " +
+                    "path=${annotationFile.absolutePath.logPreview(140)}"
+            }
+            onLocalSidecarsChanged()
         }
-        onLocalSidecarsChanged()
     }
 }
 
@@ -76,13 +98,23 @@ internal fun DesktopPdfBookmarkSidecarEffect(
 
     LaunchedEffect(documentHandleId, bookmarks, bookmarksLoaded) {
         if (!bookmarksLoaded) return@LaunchedEffect
-        withContext(Dispatchers.IO) {
+        val changed = withContext(Dispatchers.IO) {
             runCatching {
-                bookmarkFile.parentFile?.mkdirs()
-                bookmarkFile.writeText(SharedPdfBookmarkSerializer.encode(bookmarks))
-            }
+                val nextJson = SharedPdfBookmarkSerializer.encode(bookmarks)
+                when {
+                    bookmarks.isEmpty() && !bookmarkFile.isFile -> false
+                    bookmarkFile.isFile && bookmarkFile.readText() == nextJson -> false
+                    else -> {
+                        bookmarkFile.parentFile?.mkdirs()
+                        bookmarkFile.writeText(nextJson)
+                        true
+                    }
+                }
+            }.getOrDefault(false)
+        }
+        if (changed) {
+            onLocalSidecarsChanged()
         }
-        onLocalSidecarsChanged()
     }
 }
 
@@ -177,3 +209,7 @@ internal fun DesktopPdfSearchResultsEffect(
         onSearchResultsChange(results)
     }
 }
+
+private fun File.lastModifiedIfFileForCloudLog(): Long {
+    return if (isFile) lastModified() else 0L
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfSidecars.kt

@@ -1,27 +1,49 @@
 package com.aryan.reader.desktop
 
 import java.io.File
+import java.security.MessageDigest
 import java.util.Base64
 
-private const val DesktopPdfSearchIndexHeader = "EpistemePdfSearchIndex\t1"
+private const val DesktopPdfSearchIndexHeader = "EpistemePdfSearchIndex\t2"
 
 internal fun desktopPdfAnnotationFile(documentPath: String): File {
-    val safeName = documentPath.hashCode().toString().replace("-", "n")
-    return File(desktopUserDataRoot(), "annotations/pdf_$safeName.json")
+    val safeName = desktopPdfDocumentKey(documentPath)
+    val legacyName = desktopPdfLegacyDocumentKey(documentPath)
+    return sidecarFileWithLegacyMigration(
+        file = File(desktopUserDataRoot(), "annotations/pdf_$safeName.json"),
+        legacyFile = File(desktopUserDataRoot(), "annotations/pdf_$legacyName.json")
+    )
+}
+
+internal fun desktopPdfAnnotationDeletionFile(documentPath: String): File {
+    val safeName = desktopPdfDocumentKey(documentPath)
+    val legacyName = desktopPdfLegacyDocumentKey(documentPath)
+    return sidecarFileWithLegacyMigration(
+        file = File(desktopUserDataRoot(), "annotations/pdf_${safeName}_deleted_annotations.json"),
+        legacyFile = File(desktopUserDataRoot(), "annotations/pdf_${legacyName}_deleted_annotations.json")
+    )
 }
 
 internal fun desktopPdfBookmarkFile(documentPath: String): File {
-    val safeName = documentPath.hashCode().toString().replace("-", "n")
-    return File(desktopUserDataRoot(), "annotations/pdf_${safeName}_bookmarks.json")
+    val safeName = desktopPdfDocumentKey(documentPath)
+    val legacyName = desktopPdfLegacyDocumentKey(documentPath)
+    return sidecarFileWithLegacyMigration(
+        file = File(desktopUserDataRoot(), "annotations/pdf_${safeName}_bookmarks.json"),
+        legacyFile = File(desktopUserDataRoot(), "annotations/pdf_${legacyName}_bookmarks.json")
+    )
 }
 
 internal fun desktopPdfRichTextFile(documentPath: String): File {
-    val safeName = documentPath.hashCode().toString().replace("-", "n")
-    return File(desktopUserDataRoot(), "annotations/pdf_${safeName}_rich_text.json")
+    val safeName = desktopPdfDocumentKey(documentPath)
+    val legacyName = desktopPdfLegacyDocumentKey(documentPath)
+    return sidecarFileWithLegacyMigration(
+        file = File(desktopUserDataRoot(), "annotations/pdf_${safeName}_rich_text.json"),
+        legacyFile = File(desktopUserDataRoot(), "annotations/pdf_${legacyName}_rich_text.json")
+    )
 }
 
 internal fun desktopPdfSearchIndexFile(documentPath: String): File {
-    val safeName = documentPath.hashCode().toString().replace("-", "n")
+    val safeName = desktopPdfDocumentKey(documentPath)
     return File(desktopUserCacheRoot(), "search/pdf_${safeName}_text_index.tsv")
 }
 
@@ -38,7 +60,7 @@ internal fun restoreDesktopPdfSearchIndex(document: DesktopPdfDocument, indexFil
             if (parts.size == 2) parts[0] to parts[1] else null
         }
         .toMap()
-    val isFresh = metadata["pathHash"] == document.path.hashCode().toString() &&
+    val isFresh = metadata["pathKey"] == desktopPdfDocumentKey(document.path) &&
         metadata["fileSize"] == sourceFile.length().toString() &&
         metadata["lastModified"] == sourceFile.lastModified().toString() &&
         metadata["pageCount"] == document.pageCount.toString()
@@ -65,7 +87,7 @@ internal fun saveDesktopPdfSearchIndex(document: DesktopPdfDocument, indexFile:
     val encoder = Base64.getEncoder()
     val payload = buildString {
         appendLine(DesktopPdfSearchIndexHeader)
-        appendLine("pathHash\t${document.path.hashCode()}")
+        appendLine("pathKey\t${desktopPdfDocumentKey(document.path)}")
         appendLine("fileSize\t${sourceFile.length()}")
         appendLine("lastModified\t${sourceFile.lastModified()}")
         appendLine("pageCount\t${document.pageCount}")
@@ -81,3 +103,30 @@ internal fun saveDesktopPdfSearchIndex(document: DesktopPdfDocument, indexFile:
         indexFile.writeText(payload, Charsets.UTF_8)
     }
 }
+
+internal fun desktopPdfDocumentKey(documentPath: String): String {
+    val normalizedPath = runCatching { File(documentPath).canonicalPath }
+        .getOrElse { documentPath.trim() }
+    return sha256Hex(normalizedPath).take(32)
+}
+
+private fun desktopPdfLegacyDocumentKey(documentPath: String): String {
+    return documentPath.hashCode().toString().replace("-", "n")
+}
+
+private fun sidecarFileWithLegacyMigration(file: File, legacyFile: File): File {
+    if (!file.exists() && legacyFile.isFile && legacyFile != file) {
+        runCatching {
+            file.parentFile?.mkdirs()
+            if (!legacyFile.renameTo(file)) {
+                legacyFile.copyTo(file, overwrite = false)
+            }
+        }
+    }
+    return file
+}
+
+private fun sha256Hex(value: String): String {
+    val digest = MessageDigest.getInstance("SHA-256").digest(value.toByteArray(Charsets.UTF_8))
+    return digest.joinToString("") { "%02x".format(it) }
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfSyncSidecars.kt

@@ -0,0 +1,156 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.BookItem
+import com.aryan.reader.shared.FileType
+import com.aryan.reader.shared.pdf.SharedPdfAnnotationSerializer
+import com.aryan.reader.shared.pdf.SharedPdfAnnotationSidecarCodec
+import com.aryan.reader.shared.pdf.SharedPdfBookmark
+import com.aryan.reader.shared.pdf.SharedPdfBookmarkSerializer
+import com.aryan.reader.shared.pdf.SharedPdfRichTextSerializer
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonArray
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonNull
+import kotlinx.serialization.json.JsonObject
+import kotlinx.serialization.json.JsonPrimitive
+import kotlinx.serialization.json.contentOrNull
+import kotlinx.serialization.json.intOrNull
+import kotlinx.serialization.json.jsonArray
+import kotlinx.serialization.json.jsonObject
+import kotlinx.serialization.json.jsonPrimitive
+import java.io.File
+
+private val desktopPdfSyncJson = Json {
+    ignoreUnknownKeys = true
+    prettyPrint = true
+    encodeDefaults = true
+}
+
+internal fun desktopPdfAnnotationElementForSync(rawJson: String): JsonElement? {
+    val annotations = SharedPdfAnnotationSerializer.decode(rawJson)
+    if (annotations.isEmpty()) return null
+    return SharedPdfAnnotationSidecarCodec.encodeAnnotationsElement(annotations)
+}
+
+internal fun desktopPdfRichTextElementForSync(rawJson: String): JsonElement? {
+    val element = runCatching { desktopPdfSyncJson.parseToJsonElement(rawJson) }.getOrNull()
+        ?: return null
+    val document = SharedPdfRichTextSerializer.decodeElement(element)
+    if (document.text.isEmpty() && document.spans.isEmpty()) return null
+    return SharedPdfRichTextSerializer.encodeElement(document)
+}
+
+internal fun desktopPdfBookmarksMetadataJson(book: BookItem): String? {
+    if (book.type != FileType.PDF) return null
+    val path = book.path?.takeIf { it.isNotBlank() } ?: return null
+    val bookmarkFile = desktopPdfBookmarkFile(path).takeIf { it.isFile } ?: return null
+    return desktopPdfBookmarksMetadataJson(
+        bookmarks = SharedPdfBookmarkSerializer.decode(bookmarkFile.readText()),
+        lastPageIndex = book.lastPageIndex
+    )
+}
+
+internal fun desktopPdfBookmarksMetadataJson(
+    bookmarks: List<SharedPdfBookmark>,
+    lastPageIndex: Int?
+): String {
+    val totalPages = maxOf(
+        (lastPageIndex ?: 0) + 1,
+        (bookmarks.maxOfOrNull { it.pageIndex } ?: 0) + 1
+    ).coerceAtLeast(1)
+    return desktopPdfSyncJson.encodeToString(
+        JsonElement.serializer(),
+        JsonArray(
+            bookmarks.map { bookmark ->
+                JsonObject(
+                    mapOf(
+                        "pageIndex" to JsonPrimitive(bookmark.pageIndex.coerceAtLeast(0)),
+                        "title" to JsonPrimitive(bookmark.label.ifBlank { "Page ${bookmark.pageIndex + 1}" }),
+                        "totalPages" to JsonPrimitive(totalPages)
+                    )
+                )
+            }
+        )
+    )
+}
+
+internal fun desktopPdfBookmarkMetadataTimestamp(book: BookItem): Long {
+    if (book.type != FileType.PDF) return 0L
+    val path = book.path?.takeIf { it.isNotBlank() } ?: return 0L
+    return desktopPdfBookmarkFile(path).lastModifiedIfFile()
+}
+
+internal fun importDesktopPdfBookmarksMetadata(
+    book: BookItem,
+    bookmarksJson: String?,
+    timestamp: Long
+): Boolean {
+    if (book.type != FileType.PDF) return false
+    val path = book.path?.takeIf { it.isNotBlank() } ?: return false
+    val rawJson = bookmarksJson?.takeIf { it.isNotBlank() } ?: return false
+    val bookmarks = desktopPdfBookmarksFromMetadataJson(rawJson)
+    val bookmarkFile = desktopPdfBookmarkFile(path)
+    val localTimestamp = bookmarkFile.lastModifiedIfFile()
+    if (timestamp <= localTimestamp + 1000L) return false
+
+    if (bookmarks.isEmpty()) {
+        if (bookmarkFile.isFile) bookmarkFile.delete()
+        return true
+    }
+
+    bookmarkFile.parentFile?.mkdirs()
+    bookmarkFile.writeText(SharedPdfBookmarkSerializer.encode(bookmarks))
+    bookmarkFile.setLastModified(timestamp)
+    return true
+}
+
+internal fun desktopPdfBookmarksFromMetadataJson(rawJson: String): List<SharedPdfBookmark> {
+    val root = runCatching { desktopPdfSyncJson.parseToJsonElement(rawJson) }.getOrNull()
+        ?: return emptyList()
+
+    root.jsonArrayOrNull()?.let { androidBookmarks ->
+        return androidBookmarks.mapNotNull { element ->
+            val obj = element.jsonObjectOrNull() ?: return@mapNotNull null
+            val pageIndex = obj.int("pageIndex") ?: return@mapNotNull null
+            SharedPdfBookmark(
+                pageIndex = pageIndex.coerceAtLeast(0),
+                label = obj.string("title") ?: obj.string("label") ?: "Page ${pageIndex + 1}",
+                createdAt = obj.longString("createdAt") ?: 0L
+            )
+        }
+    }
+
+    return SharedPdfBookmarkSerializer.decode(rawJson)
+}
+
+private fun File.lastModifiedIfFile(): Long {
+    return if (isFile()) lastModified() else 0L
+}
+
+private fun JsonElement.jsonArrayOrNull(): JsonArray? {
+    if (this is JsonNull) return null
+    return runCatching { jsonArray }.getOrNull()
+}
+
+private fun JsonElement.jsonObjectOrNull(): JsonObject? {
+    if (this is JsonNull) return null
+    return runCatching { jsonObject }.getOrNull()
+}
+
+private fun JsonObject.string(name: String): String? {
+    return this[name]
+        ?.takeUnless { it is JsonNull }
+        ?.jsonPrimitive
+        ?.contentOrNull
+        ?.takeIf { it.isNotBlank() }
+}
+
+private fun JsonObject.int(name: String): Int? {
+    return this[name]?.takeUnless { it is JsonNull }?.jsonPrimitive?.intOrNull
+}
+
+private fun JsonObject.longString(name: String): Long? {
+    return string(name)?.toLongOrNull()
+        ?: this[name]?.takeUnless { it is JsonNull }?.jsonPrimitive?.contentOrNull?.toLongOrNull()
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfTheme.kt

@@ -2,12 +2,15 @@ package com.aryan.reader.desktop
 
 import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.isSpecified
+import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
 import com.aryan.reader.shared.PdfDisplayMode
 import com.aryan.reader.shared.ReaderTheme
+import com.aryan.reader.shared.pdf.pdfVerticalPageGapDp
 
-internal val DesktopDefaultPdfDisplayMode = PdfDisplayMode.VERTICAL_SCROLL
+internal val DesktopDefaultPdfDisplayMode = PdfDisplayMode.PAGINATION
 internal val DesktopDefaultPdfVerticalPageGap = 8.dp
+internal val DesktopDefaultPdfSpreadPageGap = 18.dp
 
 internal fun desktopPdfPageBackgroundColor(
     theme: ReaderTheme,
@@ -28,3 +31,26 @@ internal fun desktopPdfVerticalViewportBackgroundColor(
 ): Color {
     return if (isPageGapVisible) gapBackgroundColor else pageBackgroundColor
 }
+
+internal fun desktopPdfViewportBackgroundColor(
+    displayMode: PdfDisplayMode,
+    pageBackgroundColor: Color,
+    appBackgroundColor: Color,
+    isVerticalPageGapVisible: Boolean
+): Color {
+    return when (displayMode) {
+        PdfDisplayMode.VERTICAL_SCROLL -> desktopPdfVerticalViewportBackgroundColor(
+            pageBackgroundColor = pageBackgroundColor,
+            gapBackgroundColor = appBackgroundColor,
+            isPageGapVisible = isVerticalPageGapVisible
+        )
+        PdfDisplayMode.PAGINATION -> appBackgroundColor
+    }
+}
+
+internal fun desktopPdfSpreadPageGapDp(
+    isPageGapVisible: Boolean
+): Dp = pdfVerticalPageGapDp(
+    isPageGapVisible = isPageGapVisible,
+    defaultGap = DesktopDefaultPdfSpreadPageGap
+)

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPdfZoom.kt

@@ -22,6 +22,7 @@ import kotlin.math.exp
 import kotlin.math.roundToInt
 
 private const val DesktopPdfZoomGestureFrameMillis = 16L
+private const val DesktopPdfZoomPreviewTolerance = 0.0001f
 internal const val DesktopPdfPaginationFastFirstRenderMaxScale = 2.0f
 
 internal fun desktopPdfScrollZoomFactor(scrollDelta: Float): Float {
@@ -117,19 +118,320 @@ internal fun desktopPdfPaginationFirstRenderScale(
     return requestedScale.coerceAtMost(DesktopPdfPaginationFastFirstRenderMaxScale)
 }
 
+internal fun desktopPdfRenderBelongsToPage(
+    renderedPageIndex: Int?,
+    requestedPageIndex: Int
+): Boolean {
+    return renderedPageIndex == requestedPageIndex
+}
+
+internal fun desktopPdfRenderScaleNeedsUpgrade(
+    renderedScale: Float?,
+    requestedScale: Float
+): Boolean {
+    if (renderedScale == null) return true
+    if (!requestedScale.isFinite() || requestedScale <= 0f) return false
+    if (!renderedScale.isFinite() || renderedScale <= 0f) return true
+    return requestedScale - renderedScale > DesktopPdfRenderScaleTolerance
+}
+
+internal fun desktopPdfSpreadZoomAnchorPageIndex(
+    viewportRootOffset: Offset,
+    anchor: Offset?,
+    visiblePageIndices: List<Int>,
+    pageRootOffsets: Map<Int, Offset>,
+    pageSizes: Map<Int, IntSize>,
+    fallbackPageIndex: Int
+): Int {
+    if (anchor == null || visiblePageIndices.isEmpty()) return fallbackPageIndex
+    if (!anchor.x.isFinite() || !anchor.y.isFinite()) return fallbackPageIndex
+    val rootAnchor = viewportRootOffset + anchor
+    if (!rootAnchor.x.isFinite() || !rootAnchor.y.isFinite()) return fallbackPageIndex
+    val candidates = visiblePageIndices.mapNotNull { pageIndex ->
+        pageRootOffsets[pageIndex]?.let { root ->
+            pageIndex to root
+        }
+    }
+    if (candidates.isEmpty()) return fallbackPageIndex
+    candidates.firstOrNull { (pageIndex, root) ->
+        val size = pageSizes[pageIndex] ?: return@firstOrNull false
+        val width = size.width.toFloat()
+        val height = size.height.toFloat()
+        rootAnchor.x >= root.x &&
+            rootAnchor.x <= root.x + width &&
+            rootAnchor.y >= root.y &&
+            rootAnchor.y <= root.y + height
+    }?.let { return it.first }
+    return candidates.minByOrNull { (pageIndex, root) ->
+        val size = pageSizes[pageIndex]
+        val dx: Float
+        val dy: Float
+        if (size == null) {
+            dx = rootAnchor.x - root.x
+            dy = rootAnchor.y - root.y
+        } else {
+            val right = root.x + size.width.toFloat()
+            val bottom = root.y + size.height.toFloat()
+            dx = when {
+                rootAnchor.x < root.x -> root.x - rootAnchor.x
+                rootAnchor.x > right -> rootAnchor.x - right
+                else -> 0f
+            }
+            dy = when {
+                rootAnchor.y < root.y -> root.y - rootAnchor.y
+                rootAnchor.y > bottom -> rootAnchor.y - bottom
+                else -> 0f
+            }
+        }
+        dx * dx + dy * dy
+    }?.first ?: fallbackPageIndex
+}
+
 internal data class DesktopPdfZoomPreview(
     val baseZoom: Float,
     val zoom: Float,
     val anchor: Offset?,
     val displayMode: PdfDisplayMode,
-    val pageIndex: Int?
+    val pageIndex: Int?,
+    val viewportRootOffset: Offset = Offset.Zero,
+    val pageRootOffset: Offset? = null,
+    val commitTargetHorizontalScroll: Int? = null,
+    val commitTargetVerticalScroll: Int? = null,
+    val diagnosticSequence: Int = 0
 )
 
+internal data class DesktopPdfZoomScrollBounds(
+    val currentHorizontalScroll: Int? = null,
+    val maxHorizontalScroll: Int? = null,
+    val currentVerticalScroll: Int? = null,
+    val maxVerticalScroll: Int? = null
+)
+
+internal interface DesktopPdfLayoutScrollPrediction {
+    val maxHorizontalScroll: Int
+    val maxVerticalScroll: Int
+}
+
+internal data class DesktopPdfSinglePageLayoutPrediction(
+    val rootOffset: Offset,
+    override val maxHorizontalScroll: Int,
+    override val maxVerticalScroll: Int
+) : DesktopPdfLayoutScrollPrediction
+
+internal data class DesktopPdfSpreadLayoutPrediction(
+    val pageRootOffsets: Map<Int, Offset>,
+    override val maxHorizontalScroll: Int,
+    override val maxVerticalScroll: Int
+) : DesktopPdfLayoutScrollPrediction
+
 internal data class DesktopPdfCachedPageRender(
     val render: DesktopPdfPageRender,
     val scale: Float
 )
 
+internal data class DesktopPdfNavigationZoomSnapshot(
+    val zoom: Float,
+    val horizontalScroll: Int,
+    val verticalScroll: Int
+)
+
+internal fun desktopPdfNavigationZoomSnapshot(
+    preview: DesktopPdfZoomPreview?,
+    currentHorizontalScroll: Int,
+    currentVerticalScroll: Int
+): DesktopPdfNavigationZoomSnapshot? {
+    val activePreview = preview ?: return null
+    val baseZoom = activePreview.baseZoom.takeIf { it.isFinite() && it > 0f } ?: return null
+    val targetZoom = activePreview.zoom.takeIf { it.isFinite() && it > 0f } ?: return null
+    val anchor = activePreview.anchor
+    return DesktopPdfNavigationZoomSnapshot(
+        zoom = targetZoom,
+        horizontalScroll = anchor?.let {
+            desktopPdfAnchoredScrollTarget(currentHorizontalScroll, it.x, baseZoom, targetZoom)
+        } ?: currentHorizontalScroll.coerceAtLeast(0),
+        verticalScroll = anchor?.let {
+            desktopPdfAnchoredScrollTarget(currentVerticalScroll, it.y, baseZoom, targetZoom)
+        } ?: currentVerticalScroll.coerceAtLeast(0)
+    )
+}
+
+internal fun desktopPdfZoomPreviewMatchesScale(
+    preview: DesktopPdfZoomPreview,
+    scale: Float
+): Boolean {
+    return abs(preview.baseZoom - scale) <= DesktopPdfZoomPreviewTolerance ||
+        abs(preview.zoom - scale) <= DesktopPdfZoomPreviewTolerance
+}
+
+internal fun desktopPdfReachableScrollDelta(
+    currentScroll: Int?,
+    maxScroll: Int?,
+    requestedDelta: Int
+): Int {
+    if (currentScroll == null || maxScroll == null) return requestedDelta
+    val safeMax = maxScroll.coerceAtLeast(0)
+    val safeCurrent = currentScroll.coerceIn(0, safeMax)
+    val targetScroll = (safeCurrent + requestedDelta).coerceIn(0, safeMax)
+    return targetScroll - safeCurrent
+}
+
+internal fun desktopPdfReachableScrollDelta(
+    requestedDelta: IntOffset,
+    scrollBounds: DesktopPdfZoomScrollBounds?
+): IntOffset {
+    if (scrollBounds == null) return requestedDelta
+    return IntOffset(
+        x = desktopPdfReachableScrollDelta(
+            currentScroll = scrollBounds.currentHorizontalScroll,
+            maxScroll = scrollBounds.maxHorizontalScroll,
+            requestedDelta = requestedDelta.x
+        ),
+        y = desktopPdfReachableScrollDelta(
+            currentScroll = scrollBounds.currentVerticalScroll,
+            maxScroll = scrollBounds.maxVerticalScroll,
+            requestedDelta = requestedDelta.y
+        )
+    )
+}
+
+internal fun desktopPdfZoomScrollBoundsWithCommitTargets(
+    preview: DesktopPdfZoomPreview?,
+    currentHorizontalScroll: Int,
+    maxHorizontalScroll: Int,
+    currentVerticalScroll: Int? = null,
+    maxVerticalScroll: Int? = null
+): DesktopPdfZoomScrollBounds {
+    return DesktopPdfZoomScrollBounds(
+        currentHorizontalScroll = currentHorizontalScroll,
+        maxHorizontalScroll = maxOf(maxHorizontalScroll, preview?.commitTargetHorizontalScroll ?: 0),
+        currentVerticalScroll = currentVerticalScroll,
+        maxVerticalScroll = maxVerticalScroll?.let {
+            maxOf(it, preview?.commitTargetVerticalScroll ?: 0)
+        }
+    )
+}
+
+internal fun desktopPdfSinglePageLayoutPrediction(
+    viewportRootOffset: Offset,
+    viewportSize: IntSize,
+    pageCanvasSize: IntSize,
+    horizontalScroll: Int,
+    verticalScroll: Int,
+    paddingPx: Float
+): DesktopPdfSinglePageLayoutPrediction? {
+    if (viewportSize.width <= 0 || viewportSize.height <= 0) return null
+    if (pageCanvasSize.width <= 0 || pageCanvasSize.height <= 0) return null
+    if (!viewportRootOffset.x.isFinite() || !viewportRootOffset.y.isFinite()) return null
+    if (!paddingPx.isFinite() || paddingPx < 0f) return null
+    val viewportWidth = viewportSize.width.toFloat()
+    val viewportHeight = viewportSize.height.toFloat()
+    val pageWidth = pageCanvasSize.width.toFloat()
+    val contentWidth = (viewportWidth - paddingPx * 2f).coerceAtLeast(0f)
+    val maxHorizontalScroll = (pageWidth + paddingPx * 2f - viewportWidth)
+        .roundToInt()
+        .coerceAtLeast(0)
+    val maxVerticalScroll = (pageCanvasSize.height.toFloat() + paddingPx * 2f - viewportHeight)
+        .roundToInt()
+        .coerceAtLeast(0)
+    val safeHorizontalScroll = horizontalScroll.coerceIn(0, maxHorizontalScroll)
+    val safeVerticalScroll = verticalScroll.coerceIn(0, maxVerticalScroll)
+    val pageX = if (pageWidth <= contentWidth) {
+        ((viewportWidth - pageWidth) / 2f) - safeHorizontalScroll.toFloat()
+    } else {
+        paddingPx - safeHorizontalScroll.toFloat()
+    }
+    val pageY = paddingPx - safeVerticalScroll.toFloat()
+    return DesktopPdfSinglePageLayoutPrediction(
+        rootOffset = Offset(
+            x = viewportRootOffset.x + pageX,
+            y = viewportRootOffset.y + pageY
+        ),
+        maxHorizontalScroll = maxHorizontalScroll,
+        maxVerticalScroll = maxVerticalScroll
+    )
+}
+
+internal fun desktopPdfSpreadLayoutPrediction(
+    viewportRootOffset: Offset,
+    viewportSize: IntSize,
+    visiblePageIndices: List<Int>,
+    pageCanvasSizes: Map<Int, IntSize>,
+    horizontalScroll: Int,
+    verticalScroll: Int,
+    paddingPx: Float,
+    pageGapPx: Float
+): DesktopPdfSpreadLayoutPrediction? {
+    if (viewportSize.width <= 0 || viewportSize.height <= 0) return null
+    if (visiblePageIndices.isEmpty()) return null
+    if (!viewportRootOffset.x.isFinite() || !viewportRootOffset.y.isFinite()) return null
+    if (!paddingPx.isFinite() || paddingPx < 0f) return null
+    if (!pageGapPx.isFinite() || pageGapPx < 0f) return null
+    val pageSizes = visiblePageIndices.map { pageIndex ->
+        val pageSize = pageCanvasSizes[pageIndex] ?: return null
+        if (pageSize.width <= 0 || pageSize.height <= 0) return null
+        pageSize
+    }
+    val viewportWidth = viewportSize.width.toFloat()
+    val viewportHeight = viewportSize.height.toFloat()
+    val rowWidth = pageSizes.sumOf { it.width }.toFloat() +
+        (pageGapPx * (pageSizes.size - 1).coerceAtLeast(0))
+    val rowHeight = pageSizes.maxOf { it.height }.toFloat()
+    val contentWidth = (viewportWidth - paddingPx * 2f).coerceAtLeast(0f)
+    val maxHorizontalScroll = (rowWidth + paddingPx * 2f - viewportWidth)
+        .roundToInt()
+        .coerceAtLeast(0)
+    val maxVerticalScroll = (rowHeight + paddingPx * 2f - viewportHeight)
+        .roundToInt()
+        .coerceAtLeast(0)
+    val safeHorizontalScroll = horizontalScroll.coerceIn(0, maxHorizontalScroll)
+    val safeVerticalScroll = verticalScroll.coerceIn(0, maxVerticalScroll)
+    val rowX = if (rowWidth <= contentWidth) {
+        ((viewportWidth - rowWidth) / 2f) - safeHorizontalScroll.toFloat()
+    } else {
+        paddingPx - safeHorizontalScroll.toFloat()
+    }
+    val rowY = paddingPx - safeVerticalScroll.toFloat()
+    var pageX = viewportRootOffset.x + rowX
+    val pageY = viewportRootOffset.y + rowY
+    val roots = visiblePageIndices.mapIndexed { index, pageIndex ->
+        val root = Offset(pageX, pageY)
+        pageX += pageSizes[index].width.toFloat() + pageGapPx
+        pageIndex to root
+    }.toMap()
+    return DesktopPdfSpreadLayoutPrediction(
+        pageRootOffsets = roots,
+        maxHorizontalScroll = maxHorizontalScroll,
+        maxVerticalScroll = maxVerticalScroll
+    )
+}
+
+internal fun desktopPdfZoomCommitPreviewTranslation(
+    viewportRootOffset: Offset,
+    oldPageRootOffset: Offset?,
+    currentAnchorPageRootOffset: Offset,
+    anchor: Offset?,
+    oldZoom: Float,
+    newZoom: Float,
+    currentZoom: Float,
+    scrollBounds: DesktopPdfZoomScrollBounds? = null
+): Offset? {
+    if (oldPageRootOffset == null || anchor == null) return null
+    if (abs(currentZoom - newZoom) > DesktopPdfZoomPreviewTolerance) return null
+    val pageDelta = desktopPdfAnchoredPageScrollDelta(
+        viewportRootOffset = viewportRootOffset,
+        oldPageRootOffset = oldPageRootOffset,
+        currentPageRootOffset = currentAnchorPageRootOffset,
+        anchor = anchor,
+        oldZoom = oldZoom,
+        newZoom = newZoom
+    ) ?: return null
+    val reachableDelta = desktopPdfReachableScrollDelta(pageDelta, scrollBounds)
+    return Offset(
+        x = if (reachableDelta.x == 0) 0f else -reachableDelta.x.toFloat(),
+        y = if (reachableDelta.y == 0) 0f else -reachableDelta.y.toFloat()
+    )
+}
+
 internal fun desktopPdfZoomPreviewPivotFraction(
     viewportRootOffset: Offset,
     pageRootOffset: Offset,
@@ -167,14 +469,39 @@ internal fun Modifier.desktopPdfZoomPreviewLayer(
     currentZoom: Float,
     viewportRootOffset: Offset,
     pageRootOffset: Offset,
-    pageCanvasSize: IntSize
+    pageCanvasSize: IntSize,
+    commitPageRootOffset: Offset? = null,
+    scrollBounds: DesktopPdfZoomScrollBounds? = null
 ): Modifier {
     val activePreview = preview ?: return this
     if (pageCanvasSize.width <= 0 || pageCanvasSize.height <= 0) return this
     if (!currentZoom.isFinite() || currentZoom <= 0f) return this
     if (!activePreview.zoom.isFinite() || activePreview.zoom <= 0f) return this
     val previewScale = activePreview.zoom / currentZoom
-    if (!previewScale.isFinite() || abs(previewScale - 1f) < 0.0001f) return this
+    val commitTranslation = desktopPdfZoomCommitPreviewTranslation(
+        viewportRootOffset = activePreview.viewportRootOffset,
+        oldPageRootOffset = activePreview.pageRootOffset,
+        currentAnchorPageRootOffset = commitPageRootOffset ?: pageRootOffset,
+        anchor = activePreview.anchor,
+        oldZoom = activePreview.baseZoom,
+        newZoom = activePreview.zoom,
+        currentZoom = currentZoom,
+        scrollBounds = scrollBounds
+    )
+    if (
+        !previewScale.isFinite() ||
+        (abs(previewScale - 1f) < DesktopPdfZoomPreviewTolerance && commitTranslation == null)
+    ) {
+        return this
+    }
+    logPdfZoomSettle {
+        "preview_layer seq=${activePreview.diagnosticSequence} kind=page currentZoom=${currentZoom.formatLogFloat()} " +
+            "previewZoom=${activePreview.zoom.formatLogFloat()} scale=${previewScale.formatLogFloat()} " +
+            "pageRoot=${pageRootOffset.formatLogOffset()} commitRoot=${commitPageRootOffset.formatLogOffset()} " +
+            "commit=${commitTranslation.formatLogOffset()} " +
+            "h=${scrollBounds?.currentHorizontalScroll ?: "none"}/${scrollBounds?.maxHorizontalScroll ?: "none"} " +
+            "v=${scrollBounds?.currentVerticalScroll ?: "none"}/${scrollBounds?.maxVerticalScroll ?: "none"}"
+    }
     val transformOrigin = activePreview.anchor?.let { anchor ->
         desktopPdfZoomPreviewPivotFraction(
             viewportRootOffset = viewportRootOffset,
@@ -188,6 +515,8 @@ internal fun Modifier.desktopPdfZoomPreviewLayer(
     return graphicsLayer {
         scaleX = previewScale
         scaleY = previewScale
+        translationX = commitTranslation?.x ?: 0f
+        translationY = commitTranslation?.y ?: 0f
         this.transformOrigin = transformOrigin
     }
 }
@@ -196,13 +525,38 @@ internal fun Modifier.desktopPdfDocumentZoomPreviewLayer(
     preview: DesktopPdfZoomPreview?,
     currentZoom: Float,
     viewportRootOffset: Offset,
-    pageRootOffset: Offset
+    pageRootOffset: Offset,
+    anchorPageRootOffset: Offset? = null,
+    scrollBounds: DesktopPdfZoomScrollBounds? = null
 ): Modifier {
     val activePreview = preview ?: return this
     if (!currentZoom.isFinite() || currentZoom <= 0f) return this
     if (!activePreview.zoom.isFinite() || activePreview.zoom <= 0f) return this
     val previewScale = activePreview.zoom / currentZoom
-    if (!previewScale.isFinite() || abs(previewScale - 1f) < 0.0001f) return this
+    val commitTranslation = desktopPdfZoomCommitPreviewTranslation(
+        viewportRootOffset = activePreview.viewportRootOffset,
+        oldPageRootOffset = activePreview.pageRootOffset,
+        currentAnchorPageRootOffset = anchorPageRootOffset ?: pageRootOffset,
+        anchor = activePreview.anchor,
+        oldZoom = activePreview.baseZoom,
+        newZoom = activePreview.zoom,
+        currentZoom = currentZoom,
+        scrollBounds = scrollBounds
+    )
+    if (
+        !previewScale.isFinite() ||
+        (abs(previewScale - 1f) < DesktopPdfZoomPreviewTolerance && commitTranslation == null)
+    ) {
+        return this
+    }
+    logPdfZoomSettle {
+        "preview_layer seq=${activePreview.diagnosticSequence} kind=document currentZoom=${currentZoom.formatLogFloat()} " +
+            "previewZoom=${activePreview.zoom.formatLogFloat()} scale=${previewScale.formatLogFloat()} " +
+            "pageRoot=${pageRootOffset.formatLogOffset()} anchorRoot=${(anchorPageRootOffset ?: pageRootOffset).formatLogOffset()} " +
+            "commit=${commitTranslation.formatLogOffset()} h=${scrollBounds?.currentHorizontalScroll ?: "none"}/" +
+            "${scrollBounds?.maxHorizontalScroll ?: "none"} v=${scrollBounds?.currentVerticalScroll ?: "none"}/" +
+            "${scrollBounds?.maxVerticalScroll ?: "none"}"
+    }
     val translation = activePreview.anchor?.let { anchor ->
         desktopPdfDocumentZoomPreviewTranslation(
             viewportRootOffset = viewportRootOffset,
@@ -214,8 +568,8 @@ internal fun Modifier.desktopPdfDocumentZoomPreviewLayer(
     return graphicsLayer {
         scaleX = previewScale
         scaleY = previewScale
-        translationX = translation.x
-        translationY = translation.y
+        translationX = translation.x + (commitTranslation?.x ?: 0f)
+        translationY = translation.y + (commitTranslation?.y ?: 0f)
         transformOrigin = TransformOrigin(0f, 0f)
     }
 }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopPlatformPaths.kt

@@ -24,14 +24,6 @@ internal data class DesktopPlatform(
     val isLinux: Boolean get() = os == DesktopOperatingSystem.LINUX
     val isWindows: Boolean get() = os == DesktopOperatingSystem.WINDOWS
 
-    val kcefBundleDirectoryName: String
-        get() = when (os) {
-            DesktopOperatingSystem.WINDOWS -> "kcef-bundle"
-            DesktopOperatingSystem.LINUX -> "kcef-bundle-linux-${architecture.resourceName}"
-            DesktopOperatingSystem.MACOS -> "kcef-bundle-macos-${architecture.resourceName}"
-            DesktopOperatingSystem.OTHER -> "kcef-bundle-${architecture.resourceName}"
-        }
-
     val pdfiumDirectoryName: String
         get() = when (os) {
             DesktopOperatingSystem.WINDOWS -> "win-${architecture.resourceName}-v8"
@@ -140,7 +132,7 @@ private fun xdgBase(
 ): File {
     return env(envName)
         ?.takeIf { it.isNotBlank() }
+        ?.takeIf { it.startsWith("/") }
         ?.let(::File)
-        ?.takeIf { it.isAbsolute }
         ?: File(userHome, fallbackRelativePath)
 }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopProScreen.kt

@@ -13,7 +13,6 @@ import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.rememberScrollState
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.filled.Cloud
 import androidx.compose.material.icons.filled.Refresh
 import androidx.compose.material.icons.filled.Star
 import androidx.compose.material.icons.filled.Verified
@@ -55,7 +54,7 @@ internal fun DesktopProScreen(
         Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(12.dp)) {
             Icon(Icons.Default.Star, contentDescription = null, modifier = Modifier.size(30.dp), tint = MaterialTheme.colorScheme.primary)
             Column(Modifier.weight(1f)) {
-                Text(readerString("desktop_pro_and_credits", "Pro and credits"), style = MaterialTheme.typography.headlineMedium, fontWeight = FontWeight.Bold)
+                Text(readerString("desktop_account_and_credits", "Account & credits"), style = MaterialTheme.typography.headlineMedium, fontWeight = FontWeight.Bold)
                 Text(
                     readerString("desktop_pro_sign_in_desc", "Sign in to check your account status on desktop."),
                     style = MaterialTheme.typography.bodyMedium,
@@ -73,7 +72,7 @@ internal fun DesktopProScreen(
             Column(Modifier.padding(18.dp), verticalArrangement = Arrangement.spacedBy(14.dp)) {
                 Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(10.dp)) {
                     Icon(Icons.Default.Verified, contentDescription = null, tint = MaterialTheme.colorScheme.primary)
-                    Text(readerString("desktop_account", "Account"), style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.SemiBold)
+                    Text(readerString("desktop_account_overview", "Account overview"), style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.SemiBold)
                 }
                 if (user == null) {
                     Text(
@@ -92,11 +91,13 @@ internal fun DesktopProScreen(
                         Text(readerString("drawer_sign_in", "Sign in with Google"))
                     }
                 } else {
-                    Text(user.displayName ?: user.email ?: readerString("desktop_signed_in", "Signed in"), style = MaterialTheme.typography.titleMedium)
-                    user.email?.let {
-                        Text(it, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
-                    }
-                    Row(horizontalArrangement = Arrangement.spacedBy(10.dp)) {
+                    Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(12.dp)) {
+                        Column(Modifier.weight(1f), verticalArrangement = Arrangement.spacedBy(2.dp)) {
+                            Text(user.displayName ?: user.email ?: readerString("desktop_signed_in", "Signed in"), style = MaterialTheme.typography.titleMedium)
+                            user.email?.let {
+                                Text(it, style = MaterialTheme.typography.bodyMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                            }
+                        }
                         OutlinedButton(onClick = onRefresh, enabled = !isBusy) {
                             Icon(Icons.Default.Refresh, contentDescription = null, modifier = Modifier.size(18.dp))
                             Spacer(Modifier.size(8.dp))
@@ -107,33 +108,26 @@ internal fun DesktopProScreen(
                         }
                     }
                 }
-                statusMessage?.takeIf { it.isNotBlank() }?.let {
-                    Text(it, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant)
-                }
-            }
-        }
 
-        Surface(
-            modifier = Modifier.fillMaxWidth(),
-            shape = MaterialTheme.shapes.medium,
-            color = MaterialTheme.colorScheme.surfaceContainerLow,
-            border = BorderStroke(1.dp, MaterialTheme.colorScheme.outlineVariant)
-        ) {
-            Column(Modifier.padding(18.dp), verticalArrangement = Arrangement.spacedBy(14.dp)) {
-                Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(10.dp)) {
-                    Icon(Icons.Default.Cloud, contentDescription = null, tint = MaterialTheme.colorScheme.primary)
-                    Text(readerString("desktop_access", "Desktop access"), style = MaterialTheme.typography.titleLarge, fontWeight = FontWeight.SemiBold)
-                }
-                Text(
-                    if (isProUser) {
-                        readerString("desktop_pro_unlocked_account", "Pro is unlocked for this account.")
-                    } else {
-                        readerString("desktop_pro_not_unlocked_account", "Pro is not unlocked for this account.")
-                    },
-                    style = MaterialTheme.typography.titleMedium
-                )
-                Text(readerString("desktop_credits_available_format", "%1\$d credits available", credits), style = MaterialTheme.typography.headlineSmall, color = MaterialTheme.colorScheme.primary)
                 HorizontalDivider()
+
+                Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(18.dp)) {
+                    DesktopAccountValue(
+                        label = readerString("desktop_plan", "Plan"),
+                        value = if (isProUser) {
+                            readerString("desktop_pro_unlocked_account", "Pro is unlocked for this account.")
+                        } else {
+                            readerString("desktop_pro_not_unlocked_account", "Pro is not unlocked for this account.")
+                        },
+                        modifier = Modifier.weight(1f)
+                    )
+                    DesktopAccountValue(
+                        label = readerString("credits_tab", "Credits"),
+                        value = readerString("desktop_credits_available_format", "%1\$d credits available", credits),
+                        modifier = Modifier.weight(1f)
+                    )
+                }
+
                 Text(
                     readerString(
                         "desktop_pro_purchase_android_desc",
@@ -142,9 +136,25 @@ internal fun DesktopProScreen(
                     style = MaterialTheme.typography.bodyMedium,
                     color = MaterialTheme.colorScheme.onSurfaceVariant
                 )
+
+                statusMessage?.takeIf { it.isNotBlank() }?.let {
+                    Text(it, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                }
             }
         }
 
         Spacer(Modifier.height(12.dp))
     }
 }
+
+@Composable
+private fun DesktopAccountValue(
+    label: String,
+    value: String,
+    modifier: Modifier = Modifier
+) {
+    Column(modifier, verticalArrangement = Arrangement.spacedBy(4.dp)) {
+        Text(label, style = MaterialTheme.typography.labelMedium, color = MaterialTheme.colorScheme.onSurfaceVariant)
+        Text(value, style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.SemiBold)
+    }
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopProfileAvatar.kt

@@ -0,0 +1,114 @@
+package com.aryan.reader.desktop
+
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.layout.Box
+import androidx.compose.material.icons.Icons
+import androidx.compose.material.icons.filled.AccountCircle
+import androidx.compose.material3.Icon
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Surface
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.LaunchedEffect
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.remember
+import androidx.compose.runtime.setValue
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.graphics.ImageBitmap
+import androidx.compose.ui.graphics.toComposeImageBitmap
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.foundation.shape.CircleShape
+import com.aryan.reader.shared.UserData
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.withContext
+import org.jetbrains.skia.Image as SkiaImage
+
+@Composable
+internal fun DesktopProfileAvatar(
+    user: UserData,
+    modifier: Modifier = Modifier
+) {
+    val photoUrl = user.photoUrl?.takeIf { it.isNotBlank() }
+    var bitmap by remember(photoUrl) { mutableStateOf(photoUrl?.let(DesktopProfileAvatarCache::peek)) }
+
+    LaunchedEffect(photoUrl) {
+        bitmap = if (photoUrl == null) {
+            null
+        } else {
+            withContext(Dispatchers.IO) {
+                DesktopProfileAvatarCache.load(photoUrl)
+            }
+        }
+    }
+
+    val imageBitmap = bitmap
+    if (imageBitmap != null) {
+        Image(
+            bitmap = imageBitmap,
+            contentDescription = null,
+            contentScale = ContentScale.Crop,
+            modifier = modifier.clip(CircleShape)
+        )
+    } else {
+        DesktopProfileAvatarFallback(user = user, modifier = modifier)
+    }
+}
+
+@Composable
+private fun DesktopProfileAvatarFallback(
+    user: UserData,
+    modifier: Modifier = Modifier
+) {
+    Surface(
+        modifier = modifier,
+        shape = CircleShape,
+        color = MaterialTheme.colorScheme.primaryContainer,
+        contentColor = MaterialTheme.colorScheme.onPrimaryContainer
+    ) {
+        Box(contentAlignment = Alignment.Center) {
+            val initial = (user.displayName ?: user.email)
+                ?.trim()
+                ?.firstOrNull()
+                ?.uppercase()
+            if (initial != null) {
+                Text(initial, style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.Bold)
+            } else {
+                Icon(Icons.Default.AccountCircle, contentDescription = null)
+            }
+        }
+    }
+}
+
+private object DesktopProfileAvatarCache {
+    private const val MaxEntries = 24
+
+    private val cache = object : LinkedHashMap<String, ImageBitmap>(MaxEntries, 0.75f, true) {
+        override fun removeEldestEntry(eldest: MutableMap.MutableEntry<String, ImageBitmap>?): Boolean {
+            return size > MaxEntries
+        }
+    }
+
+    fun peek(url: String): ImageBitmap? {
+        return synchronized(cache) { cache[url] }
+    }
+
+    fun load(url: String): ImageBitmap? {
+        peek(url)?.let { return it }
+        val bitmap = runCatching {
+            DesktopOpdsHttp.fetchBytes(url, catalog = null).toImageBitmap()
+        }.getOrNull() ?: return null
+
+        synchronized(cache) {
+            cache[url] = bitmap
+        }
+        return bitmap
+    }
+
+    private fun ByteArray.toImageBitmap(): ImageBitmap? {
+        return runCatching { SkiaImage.makeFromEncoded(this).toComposeImageBitmap() }.getOrNull()
+    }
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopReaderDefaults.kt

@@ -0,0 +1,91 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.BookItem
+import com.aryan.reader.shared.FileType
+import com.aryan.reader.shared.PdfDisplayMode
+import com.aryan.reader.shared.ReaderFeatureSurface
+import com.aryan.reader.shared.ReaderPlatform
+import com.aryan.reader.shared.SharedFileCapabilities
+import com.aryan.reader.shared.SharedReaderScreenState
+import com.aryan.reader.shared.reader.ReaderPageSpreadMode
+import com.aryan.reader.shared.reader.ReaderReadingMode
+import com.aryan.reader.shared.reader.ReaderSettings
+
+internal const val DesktopReaderDefaultsVersion = 1
+
+internal enum class DesktopReaderSettingsEngine {
+    TEXT,
+    PDF
+}
+
+internal val DesktopDefaultTextReaderSettings = ReaderSettings(
+    readingMode = ReaderReadingMode.PAGINATED,
+    pageSpreadMode = ReaderPageSpreadMode.TWO_PAGE
+)
+
+internal val DesktopDefaultPdfReaderSettings = ReaderSettings(
+    themeId = "no_theme",
+    readingMode = ReaderReadingMode.PAGINATED,
+    pageSpreadMode = ReaderPageSpreadMode.TWO_PAGE
+)
+
+internal fun FileType.desktopReaderSettingsEngine(): DesktopReaderSettingsEngine? {
+    return when (SharedFileCapabilities.surfaceFor(this, ReaderPlatform.DESKTOP)) {
+        ReaderFeatureSurface.PDF_VIEWER -> DesktopReaderSettingsEngine.PDF
+        ReaderFeatureSurface.EPUB_READER,
+        ReaderFeatureSurface.TEXT_READER -> DesktopReaderSettingsEngine.TEXT
+        null -> null
+    }
+}
+
+internal fun BookItem.usesDesktopReaderSettingsEngine(engine: DesktopReaderSettingsEngine): Boolean {
+    return type.desktopReaderSettingsEngine() == engine
+}
+
+internal fun List<BookItem>.withDesktopReaderEngineSettings(
+    engine: DesktopReaderSettingsEngine,
+    settings: ReaderSettings
+): List<BookItem> {
+    return map { book ->
+        if (book.usesDesktopReaderSettingsEngine(engine)) {
+            book.copy(readerSettings = settings)
+        } else {
+            book
+        }
+    }
+}
+
+internal fun SharedReaderScreenState.withDesktopReaderEngineDefaultSettings(
+    engine: DesktopReaderSettingsEngine,
+    settings: ReaderSettings
+): SharedReaderScreenState {
+    val engineSettings = if (engine == DesktopReaderSettingsEngine.PDF) {
+        settings.toDesktopPdfReaderSettings()
+    } else {
+        settings
+    }
+    return when (engine) {
+        DesktopReaderSettingsEngine.TEXT -> copy(
+            readerDefaultSettings = engineSettings,
+            rawLibraryBooks = rawLibraryBooks.withDesktopReaderEngineSettings(engine, engineSettings)
+        )
+        DesktopReaderSettingsEngine.PDF -> copy(
+            pdfReaderDefaultSettings = engineSettings,
+            rawLibraryBooks = rawLibraryBooks.withDesktopReaderEngineSettings(engine, engineSettings)
+        )
+    }
+}
+
+internal fun ReaderSettings.toDesktopPdfDisplayMode(): PdfDisplayMode {
+    return when (readingMode) {
+        ReaderReadingMode.PAGINATED -> PdfDisplayMode.PAGINATION
+        ReaderReadingMode.VERTICAL -> PdfDisplayMode.VERTICAL_SCROLL
+    }
+}
+
+internal fun PdfDisplayMode.toDesktopReaderReadingMode(): ReaderReadingMode {
+    return when (this) {
+        PdfDisplayMode.PAGINATION -> ReaderReadingMode.PAGINATED
+        PdfDisplayMode.VERTICAL_SCROLL -> ReaderReadingMode.VERTICAL
+    }
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopReaderDiagnostics.kt

@@ -1,14 +1,26 @@
 package com.aryan.reader.desktop
 
 import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.unit.IntOffset
 import androidx.compose.ui.unit.IntSize
+import com.aryan.reader.shared.ReaderLocator
 
 private const val PdfZoomPerfLogTag = "EpistemePdfZoomPerf"
+private const val PdfZoomSettleLogTag = "EpistemePdfZoomSettle"
 private const val PdfLinkLogTag = "EpistemePdfLink"
+private const val PdfChromeTapLogTag = "EpistemePdfChromeTap"
 private const val EpubLinkLogTag = "EpistemeEpubLink"
 private const val EpubPaginationLogTag = "EpistemeEpubPagination"
+private const val EpubCutoffLogTag = "EpistemeEpubCutoff"
 private const val ReaderGapLogTag = "EpistemeReaderGap"
 private const val EpubSelectionDebugLogTag = "EPUB_SELECTION_DEBUG"
+private const val EpubHighlightFlowLogTag = "EpistemeEpubHighlightFlow"
+private const val DesktopHighlightMapLogTag = "EpistemeDesktopHighlightMap"
+private const val DesktopPositionTraceLogTag = "EpistemeDesktopPositionTrace"
+private const val DesktopReaderCloseLogTag = "EpistemeDesktopReaderClose"
+private const val DesktopNativeWebViewLogTag = "EpistemeNativeWebView"
+private const val WebViewLayoutLogTag = "EpistemeWebViewLayout"
+private const val ReaderModeSwitchLogTag = "EpistemeReaderModeSwitch"
 
 internal fun logPdfSelection(message: String) {
 }
@@ -21,10 +33,26 @@ internal fun logPdfZoomPerf(message: () -> String) {
     logDesktopDiagnostic(PdfZoomPerfLogTag, message)
 }
 
+internal fun logPdfZoomSettle(message: String) {
+    logDesktopDiagnostic(PdfZoomSettleLogTag) { message }
+}
+
+internal fun logPdfZoomSettle(message: () -> String) {
+    logDesktopDiagnostic(PdfZoomSettleLogTag, message)
+}
+
 internal fun logPdfLink(message: String) {
     logDesktopDiagnostic(PdfLinkLogTag) { message }
 }
 
+internal fun logPdfChromeTap(message: String) {
+    logDesktopDiagnostic(PdfChromeTapLogTag) { message }
+}
+
+internal fun logPdfChromeTap(message: () -> String) {
+    logDesktopDiagnostic(PdfChromeTapLogTag, message)
+}
+
 internal fun logEpubLink(message: String) {
     logDesktopDiagnostic(EpubLinkLogTag) { message }
 }
@@ -33,6 +61,10 @@ internal fun logEpubPagination(message: String) {
     logDesktopDiagnostic(EpubPaginationLogTag) { message }
 }
 
+internal fun logEpubCutoff(message: String) {
+    logDesktopDiagnostic(EpubCutoffLogTag) { message }
+}
+
 internal fun logReaderGap(message: String) {
     logDesktopDiagnostic(ReaderGapLogTag) { message }
 }
@@ -41,6 +73,38 @@ internal fun logEpubSelectionDebug(message: String) {
     logDesktopDiagnostic(EpubSelectionDebugLogTag) { message }
 }
 
+internal fun logEpubHighlightFlow(message: String) {
+    logDesktopDiagnostic(EpubHighlightFlowLogTag) { message }
+}
+
+internal fun logDesktopHighlightMap(message: String) {
+    logDesktopDiagnostic(DesktopHighlightMapLogTag) { message }
+}
+
+internal fun logDesktopPositionTrace(message: String) {
+    logDesktopDiagnostic(DesktopPositionTraceLogTag) { message }
+}
+
+internal fun logDesktopPositionTrace(message: () -> String) {
+    logDesktopDiagnostic(DesktopPositionTraceLogTag, message)
+}
+
+internal fun logDesktopReaderClose(message: String) {
+    logDesktopDiagnostic(DesktopReaderCloseLogTag) { message }
+}
+
+internal fun logDesktopWebView2(message: String) {
+    logDesktopDiagnostic(DesktopNativeWebViewLogTag) { message }
+}
+
+internal fun logWebViewLayoutDiag(message: String) {
+    logDesktopDiagnostic(WebViewLayoutLogTag) { message }
+}
+
+internal fun logReaderModeSwitch(message: String) {
+    logDesktopDiagnostic(ReaderModeSwitchLogTag) { message }
+}
+
 internal fun DesktopPdfLinkTarget.formatLogTarget(): String {
     return "dest=${destPageIndex?.let { it + 1 } ?: "null"} uri=\"${uri.orEmpty().logPreview()}\""
 }
@@ -54,6 +118,11 @@ internal fun Offset?.formatLogOffset(): String {
     return "${x.formatLogFloat()},${y.formatLogFloat()}"
 }
 
+internal fun IntOffset?.formatLogIntOffset(): String {
+    if (this == null) return "none"
+    return "${this.x},${this.y}"
+}
+
 internal fun IntSize.formatLogSize(): String {
     return "${width}x${height}"
 }
@@ -66,3 +135,12 @@ internal fun DesktopPdfCharHit?.formatLogHit(prefix: String): String {
         "${prefix}X=${point.x.formatLogFloat()} ${prefix}Y=${point.y.formatLogFloat()} " +
         "${prefix}Nx=${normalized.x.formatLogFloat()} ${prefix}Ny=${normalized.y.formatLogFloat()}"
 }
+
+internal fun ReaderLocator?.desktopPositionTraceSummary(maxTextLength: Int = 90): String {
+    if (this == null) return "null"
+    return "chapter=${chapterIndex ?: "null"} page=${pageIndex ?: "null"} " +
+        "offsets=${startOffset ?: "null"}..${endOffset ?: "null"} " +
+        "block=${blockIndex ?: "null"} char=${charOffset ?: "null"} " +
+        "chapterId=\"${chapterId.orEmpty().logPreview(80)}\" href=\"${href.orEmpty().logPreview(120)}\" " +
+        "cfi=\"${cfi.orEmpty().logPreview(180)}\" text=\"${textQuote.orEmpty().logPreview(maxTextLength)}\""
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopReaderOpenTrace.kt

@@ -0,0 +1,29 @@
+package com.aryan.reader.desktop
+
+internal const val DesktopReaderOpenTraceTag = "EpistemeDesktopOpenTrace"
+
+internal fun logDesktopReaderOpenTrace(message: () -> String) {
+    logDesktopDiagnostic(DesktopReaderOpenTraceTag, message)
+}
+
+internal fun Long.elapsedOpenTraceMs(nowNanos: Long = System.nanoTime()): Long {
+    return ((nowNanos - this).coerceAtLeast(0L)) / 1_000_000L
+}
+
+internal fun DesktopReaderOpening.elapsedOpenTraceMs(nowNanos: Long = System.nanoTime()): Long {
+    return startedAtNanos.elapsedOpenTraceMs(nowNanos)
+}
+
+internal fun DesktopReaderOpening.openTracePrefix(event: String): String {
+    return "event=$event requestId=$requestId bookId=\"${bookId.logPreview(80)}\" " +
+        "title=\"${title.logPreview(120)}\" format=\"$formatLabel\" elapsedMs=${elapsedOpenTraceMs()}"
+}
+
+internal fun DesktopReaderOpenResult.openTraceKind(): String {
+    return when (this) {
+        is DesktopReaderOpenResult.Failure -> "failure"
+        is DesktopReaderOpenResult.PasswordRequired -> "password_required"
+        is DesktopReaderOpenResult.Pdf -> "pdf"
+        is DesktopReaderOpenResult.Text -> "text"
+    }
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopReaderOpening.kt

@@ -10,7 +10,8 @@ internal data class DesktopReaderOpening(
     val title: String,
     val formatLabel: String,
     val returnTab: SharedAppTab,
-    val password: String? = null
+    val password: String? = null,
+    val startedAtNanos: Long = System.nanoTime()
 )
 
 internal sealed interface DesktopReaderOpenResult {

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopReaderPanels.kt

@@ -26,7 +26,6 @@ import androidx.compose.material3.HorizontalDivider
 import androidx.compose.material3.Icon
 import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Slider
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Switch
 import androidx.compose.material3.Text
@@ -49,11 +48,8 @@ import com.aryan.reader.shared.ReaderAiByokSettings
 import com.aryan.reader.shared.ReaderAiModelOption
 import com.aryan.reader.shared.ReaderAiModelOptions
 import com.aryan.reader.shared.ReaderAiResultState
-import com.aryan.reader.shared.ReaderAutoScrollState
 import com.aryan.reader.shared.ReaderCloudTtsVoices
 import com.aryan.reader.shared.ReaderExtrasState
-import com.aryan.reader.shared.ReaderExternalLookupAction
-import com.aryan.reader.shared.ReaderTtsReadScope
 import com.aryan.reader.shared.ReaderTtsReplacementPreferences
 import com.aryan.reader.shared.maskedReaderAiKey
 import com.aryan.reader.shared.ui.SharedMarkdownText
@@ -197,7 +193,7 @@ internal fun DesktopAiByokSettingsDialog(
                 DesktopSavedAiKeyRow(
                     label = readerString("provider_gemini", "Gemini"),
                     keyValue = sanitized.geminiKey,
-                    onClear = { onSettingsChange(sanitized.copy(geminiKey = "", ttsModel = "")) }
+                    onClear = { onSettingsChange(sanitized.copy(geminiKey = "")) }
                 )
                 DesktopSavedAiKeyRow(
                     label = readerString("provider_groq", "Groq"),
@@ -250,26 +246,6 @@ internal fun DesktopAiByokSettingsDialog(
 
                 HorizontalDivider()
 
-                Row(modifier = Modifier.fillMaxWidth(), verticalAlignment = Alignment.CenterVertically) {
-                    Column(modifier = Modifier.weight(1f)) {
-                        Text(readerString("options_show_ai_in_reader", "Show AI in reader"), style = MaterialTheme.typography.titleMedium)
-                        Text(
-                            readerString(
-                                "desktop_show_ai_in_reader_desc",
-                                "Matches the Android hide toggle for smart dictionary, summaries, and recaps."
-                            ),
-                            style = MaterialTheme.typography.bodySmall,
-                            color = MaterialTheme.colorScheme.onSurfaceVariant
-                        )
-                    }
-                    Switch(
-                        checked = !sanitized.hideReaderAiFeatures,
-                        onCheckedChange = { enabled ->
-                            onSettingsChange(sanitized.copy(hideReaderAiFeatures = !enabled))
-                        }
-                    )
-                }
-
                 Row(modifier = Modifier.fillMaxWidth(), verticalAlignment = Alignment.CenterVertically) {
                     Column(modifier = Modifier.weight(1f)) {
                         Text(readerString("ai_settings_use_one_model", "Use one model for all features"), style = MaterialTheme.typography.titleMedium)
@@ -320,31 +296,6 @@ internal fun DesktopAiByokSettingsDialog(
                     options = listOf(ReaderAiModelOption("gemini", GEMINI_CLOUD_TTS_MODEL)),
                     onSelected = { onSettingsChange(sanitized.copy(ttsModel = it)) }
                 )
-                Text(readerString("desktop_cloud_tts_voice", "Cloud TTS voice"), style = MaterialTheme.typography.titleSmall, fontWeight = FontWeight.SemiBold)
-                Column(verticalArrangement = Arrangement.spacedBy(6.dp)) {
-                    ReaderCloudTtsVoices.chunked(3).forEach { rowVoices ->
-                        Row(horizontalArrangement = Arrangement.spacedBy(6.dp), modifier = Modifier.horizontalScroll(rememberScrollState())) {
-                            rowVoices.forEach { voice ->
-                                FilterChip(
-                                    selected = sanitized.ttsSpeakerId == voice.id,
-                                    onClick = { onSettingsChange(sanitized.copy(ttsSpeakerId = voice.id)) },
-                                    label = {
-                                        Column {
-                                            Text(voice.name, maxLines = 1, overflow = TextOverflow.Ellipsis)
-                                            Text(
-                                                voice.description,
-                                                style = MaterialTheme.typography.labelSmall,
-                                                color = MaterialTheme.colorScheme.onSurfaceVariant,
-                                                maxLines = 1,
-                                                overflow = TextOverflow.Ellipsis
-                                            )
-                                        }
-                                    }
-                                )
-                            }
-                        }
-                    }
-                }
             }
         },
         confirmButton = {
@@ -405,53 +356,21 @@ private fun DesktopAiModelSelector(
 }
 
 @Composable
-internal fun DesktopPdfExtrasPanel(
-    pageText: String,
+internal fun DesktopPdfTtsPanel(
     extrasState: ReaderExtrasState,
     aiByokSettings: ReaderAiByokSettings,
-    externalLookupAvailable: Boolean,
     cloudTtsFeatureAvailable: Boolean,
-    onExternalLookup: (ReaderExternalLookupAction, String) -> Unit,
-    onOpenAiHub: (() -> Unit)? = null,
-    onCloudTtsStart: (ReaderTtsReadScope) -> Unit,
-    onCloudTtsPauseResume: () -> Unit,
-    onCloudTtsStop: () -> Unit,
     onCloudTtsClearCache: () -> Unit,
-    onAutoScrollChange: (ReaderAutoScrollState) -> Unit,
+    onCloudTtsVoiceChange: (String) -> Unit,
     ttsReplacementPreferences: ReaderTtsReplacementPreferences,
     ttsReplacementBookId: String,
     onTtsReplacementPreferencesChange: (ReaderTtsReplacementPreferences) -> Unit
 ) {
     val settings = aiByokSettings.sanitized()
-    val autoScroll = extrasState.autoScroll.sanitized()
 
     Column(verticalArrangement = Arrangement.spacedBy(10.dp)) {
         HorizontalDivider(modifier = Modifier.padding(vertical = 8.dp))
-        Text(readerString("desktop_extras", "Extras"), style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.Bold)
-        if (externalLookupAvailable) {
-            Row(horizontalArrangement = Arrangement.spacedBy(6.dp), modifier = Modifier.horizontalScroll(rememberScrollState())) {
-                ReaderExternalLookupAction.entries.forEach { action ->
-                    FilterChip(
-                        selected = false,
-                        enabled = pageText.isNotBlank(),
-                        onClick = { onExternalLookup(action, pageText) },
-                        label = { Text(action.title) }
-                    )
-                }
-            }
-        }
-        Row(modifier = Modifier.fillMaxWidth(), verticalAlignment = Alignment.CenterVertically) {
-            Text(readerString("menu_auto_scroll", "Auto Scroll"), modifier = Modifier.weight(1f))
-            Switch(
-                checked = autoScroll.enabled,
-                onCheckedChange = { onAutoScrollChange(autoScroll.copy(enabled = it)) }
-            )
-        }
-        Slider(
-            value = autoScroll.speed,
-            onValueChange = { onAutoScrollChange(autoScroll.copy(speed = it).sanitized()) },
-            valueRange = 12f..160f
-        )
+        Text(readerString("menu_tts_settings", "TTS"), style = MaterialTheme.typography.titleMedium, fontWeight = FontWeight.Bold)
         val ttsBusy = extrasState.cloudTts.isLoading || extrasState.cloudTts.isPlaying || extrasState.cloudTts.isPaused
         if (cloudTtsFeatureAvailable) {
             Row(modifier = Modifier.fillMaxWidth(), verticalAlignment = Alignment.CenterVertically) {
@@ -476,40 +395,38 @@ internal fun DesktopPdfExtrasPanel(
                         Text(it, style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant)
                     }
                 }
-                TextButton(
-                    enabled = settings.isCloudTtsAvailable || ttsBusy,
-                    onClick = {
-                        if (ttsBusy) {
-                            onCloudTtsStop()
-                        } else {
-                            onCloudTtsStart(ReaderTtsReadScope.BOOK)
-                        }
-                    }
-                ) {
-                    Text(if (ttsBusy) readerString("action_stop", "Stop") else readerString("action_read", "Read"))
-                }
             }
-            if (extrasState.cloudTts.isPlaying || extrasState.cloudTts.isPaused) {
+            Column(verticalArrangement = Arrangement.spacedBy(6.dp)) {
+                Text(readerString("desktop_cloud_tts_voice", "Cloud TTS voice"), fontWeight = FontWeight.SemiBold)
+                if (ttsBusy) {
+                    Text(
+                        readerString("desktop_stop_reading_change_voices", "Stop reading to change voices."),
+                        style = MaterialTheme.typography.bodySmall,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant
+                    )
+                }
                 Row(horizontalArrangement = Arrangement.spacedBy(6.dp), modifier = Modifier.horizontalScroll(rememberScrollState())) {
-                    TextButton(onClick = onCloudTtsPauseResume) {
-                        Text(if (extrasState.cloudTts.isPaused) readerString("tooltip_tts_resume", "Resume") else readerString("tooltip_tts_pause", "Pause"))
+                    ReaderCloudTtsVoices.forEach { voice ->
+                        FilterChip(
+                            selected = settings.ttsSpeakerId == voice.id,
+                            enabled = !ttsBusy,
+                            onClick = { onCloudTtsVoiceChange(voice.id) },
+                            label = {
+                                Column {
+                                    Text(voice.name, maxLines = 1, overflow = TextOverflow.Ellipsis)
+                                    Text(
+                                        voice.description,
+                                        style = MaterialTheme.typography.labelSmall,
+                                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                                        maxLines = 1,
+                                        overflow = TextOverflow.Ellipsis
+                                    )
+                                }
+                            }
+                        )
                     }
                 }
             }
-            Row(horizontalArrangement = Arrangement.spacedBy(6.dp), modifier = Modifier.horizontalScroll(rememberScrollState())) {
-                TextButton(
-                    enabled = settings.isCloudTtsAvailable && !ttsBusy && pageText.isNotBlank(),
-                    onClick = { onCloudTtsStart(ReaderTtsReadScope.PAGE) }
-                ) {
-                    Text(readerString("desktop_page", "Page"))
-                }
-                TextButton(
-                    enabled = settings.isCloudTtsAvailable && !ttsBusy && pageText.isNotBlank(),
-                    onClick = { onCloudTtsStart(ReaderTtsReadScope.BOOK) }
-                ) {
-                    Text(readerString("desktop_from_here", "From here"))
-                }
-            }
             val cacheSummary = extrasState.cloudTts.cacheSummary
             if (cacheSummary.hasCachedAudio) {
                 Text(
@@ -529,12 +446,5 @@ internal fun DesktopPdfExtrasPanel(
             bookId = ttsReplacementBookId,
             onPreferencesChange = onTtsReplacementPreferencesChange
         )
-        if (settings.areReaderAiFeaturesAvailable && onOpenAiHub != null) {
-            Row(horizontalArrangement = Arrangement.spacedBy(6.dp), modifier = Modifier.horizontalScroll(rememberScrollState())) {
-                TextButton(onClick = onOpenAiHub) {
-                    Text(readerString("desktop_ai_hub", "AI hub"))
-                }
-            }
-        }
     }
 }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopReaderScreen.kt

@@ -1,5 +1,7 @@
 package com.aryan.reader.desktop
 
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.ColumnScope
@@ -10,6 +12,7 @@ import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.key
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
@@ -17,6 +20,8 @@ import androidx.compose.runtime.rememberUpdatedState
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
+import androidx.compose.ui.layout.boundsInWindow
+import androidx.compose.ui.layout.onGloballyPositioned
 import androidx.compose.ui.layout.onSizeChanged
 import androidx.compose.ui.platform.LocalClipboardManager
 import androidx.compose.ui.platform.LocalDensity
@@ -34,19 +39,23 @@ import com.aryan.reader.shared.ReaderAutoScrollState
 import com.aryan.reader.shared.ReaderExtrasState
 import com.aryan.reader.shared.ReaderExternalLookupAction
 import com.aryan.reader.shared.ReaderHighlightPalette
+import com.aryan.reader.shared.ReaderLocator
 import com.aryan.reader.shared.ReaderToolbarPreferences
 import com.aryan.reader.shared.ReaderTtsChunk
 import com.aryan.reader.shared.ReaderTtsReadScope
 import com.aryan.reader.shared.ReaderTtsReplacementPreferences
+import com.aryan.reader.shared.ReaderTheme
 import com.aryan.reader.shared.reader.ReaderEngine
 import com.aryan.reader.shared.reader.ReaderImageReference
 import com.aryan.reader.shared.reader.ReaderLinkTarget
+import com.aryan.reader.shared.reader.ReaderPage
 import com.aryan.reader.shared.reader.ReaderReadingMode
 import com.aryan.reader.shared.reader.ReaderSettings
 import com.aryan.reader.shared.reader.ReaderSessionState
 import com.aryan.reader.shared.reader.ReaderViewportSpec
 import com.aryan.reader.shared.reader.SharedEpubPaginationCache
 import com.aryan.reader.shared.reader.SharedMeasuredEpubPaginator
+import com.aryan.reader.shared.reader.isRightToLeftPaginationEnabled
 import com.aryan.reader.shared.reader.layoutSignature
 import com.aryan.reader.shared.reduce
 import com.aryan.reader.shared.ui.DesktopEpubNativeImage
@@ -54,7 +63,12 @@ import com.aryan.reader.shared.ui.ReaderContentRenderPlan
 import com.aryan.reader.shared.ui.SharedNativePaginatedReader
 import com.aryan.reader.shared.ui.SharedNativeReaderSelectionAction
 import com.aryan.reader.shared.ui.SharedReaderScreen
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
+import kotlinx.coroutines.withContext
+import java.awt.EventQueue
+import java.awt.Window
 import java.awt.event.KeyEvent as AwtKeyEvent
 
 @Composable
@@ -64,8 +78,12 @@ internal fun DesktopReaderScreen(
     onSessionChange: (ReaderSessionState) -> Unit,
     onReturnToLibrary: (() -> Unit)? = null,
     onFullscreenChange: (Boolean) -> Unit = {},
+    readerAwtWindow: Window? = null,
     toolbarPreferences: ReaderToolbarPreferences,
     onToolbarPreferencesChange: (ReaderToolbarPreferences) -> Unit,
+    appThemeControls: (@Composable () -> Unit)? = null,
+    customReaderThemes: List<ReaderTheme>,
+    onCustomReaderThemesChange: (List<ReaderTheme>) -> Unit,
     highlightPalette: ReaderHighlightPalette,
     onHighlightPaletteChange: (ReaderHighlightPalette) -> Unit,
     ttsReplacementPreferences: ReaderTtsReplacementPreferences,
@@ -80,13 +98,13 @@ internal fun DesktopReaderScreen(
     onExternalLookup: (ReaderExternalLookupAction, String) -> Unit,
     onAiAction: (ReaderAiFeature, String) -> Unit,
     onAiResultDismiss: () -> Unit,
-    onCloudTtsToggle: (String) -> Unit,
+    onCloudTtsToggle: (String, ReaderLocator?) -> Unit,
     onCloudTtsStart: (ReaderTtsReadScope, List<ReaderTtsChunk>) -> Unit,
     onCloudTtsPauseResume: () -> Unit,
     onCloudTtsStop: () -> Unit,
     onCloudTtsClearCache: () -> Unit,
+    onCloudTtsVoiceChange: (String) -> Unit,
     onOpenAiHub: (() -> Unit)? = null,
-    onAutoScrollChange: (ReaderAutoScrollState) -> Unit,
     onDownloadReaderImage: (ReaderImageReference) -> Unit,
     readerTextureDataUri: (String) -> String?,
     readerCustomTextureIds: List<String>,
@@ -119,6 +137,18 @@ internal fun DesktopReaderScreen(
             cacheWriteScope = paginationCacheWriteScope
         )
     }
+    LaunchedEffect(session.reader.book.id) {
+        logDesktopReaderOpenTrace {
+            "event=desktop_text_reader_screen_composed bookId=\"${session.reader.book.id.logPreview(120)}\" " +
+                "title=\"${session.reader.book.title.logPreview(120)}\" mode=${session.reader.settings.readingMode} " +
+                "chapters=${session.reader.book.chapters.size} pages=${session.reader.pages.size} " +
+                "currentPage=${session.reader.currentPageIndex + 1} " +
+                "textChars=${session.reader.book.chapters.sumOf { it.plainText.length }} " +
+                "htmlChars=${session.reader.book.chapters.sumOf { it.htmlContent.length }} " +
+                "semanticBlocks=${session.reader.book.chapters.sumOf { it.semanticBlocks.size }} " +
+                "bookmarks=${session.bookmarks.size} highlights=${session.highlights.size}"
+        }
+    }
     var readerViewport by remember(session.reader.book.id) { mutableStateOf(ReaderViewportSpec(0, 0)) }
     val paginationLayoutSignature = session.reader.settings.layoutSignature()
     val paginationContentSignature = remember(session.reader.book) {
@@ -152,16 +182,40 @@ internal fun DesktopReaderScreen(
     var completedMeasuredPaginationRequest by remember(session.reader.book.id) {
         mutableStateOf<DesktopEpubPaginationRequest?>(null)
     }
+    var completedMeasuredPaginationPages by remember(session.reader.book.id) {
+        mutableStateOf(emptyList<ReaderPage>())
+    }
+    var warmMeasuredPaginationRequest by remember(session.reader.book.id) {
+        mutableStateOf<DesktopEpubPaginationRequest?>(null)
+    }
+    var warmMeasuredPaginationPages by remember(session.reader.book.id) {
+        mutableStateOf(emptyList<ReaderPage>())
+    }
     var runningMeasuredPaginationRequest by remember(session.reader.book.id) {
         mutableStateOf<DesktopEpubPaginationRequest?>(null)
     }
-    val paginatedLayoutReady = session.reader.settings.readingMode != ReaderReadingMode.PAGINATED ||
-        (measuredPaginationRequest != null && completedMeasuredPaginationRequest == measuredPaginationRequest)
+    val measuredPaginationPagesApplied = desktopMeasuredPaginationReady(
+        request = measuredPaginationRequest,
+        completedRequest = completedMeasuredPaginationRequest,
+        currentPages = session.reader.pages,
+        measuredPages = completedMeasuredPaginationPages
+    )
+    val warmMeasuredPaginationPagesApplied = desktopMeasuredPaginationReady(
+        request = measuredPaginationRequest,
+        completedRequest = warmMeasuredPaginationRequest,
+        currentPages = session.reader.pages,
+        measuredPages = warmMeasuredPaginationPages
+    )
+    val paginatedLayoutReady = desktopPaginatedLayoutReadyForDisplay(
+        readingMode = session.reader.settings.readingMode,
+        measuredPagesApplied = measuredPaginationPagesApplied
+    )
     val latestSession by rememberUpdatedState(session)
     val latestOnSessionChange by rememberUpdatedState(onSessionChange)
     var externalLinkDialogUrl by remember { mutableStateOf<String?>(null) }
     var lastHandledLink by remember { mutableStateOf<DesktopEpubHandledLink?>(null) }
     var isFullscreen by remember(session.reader.book.id) { mutableStateOf(false) }
+    val desktopReaderExtrasState = readerExtrasState.copy(autoScroll = ReaderAutoScrollState())
     val currentReaderFullscreen by rememberUpdatedState(isFullscreen)
     val currentOnReaderFullscreenChange by rememberUpdatedState(onFullscreenChange)
 
@@ -175,9 +229,12 @@ internal fun DesktopReaderScreen(
         onDismiss = { externalLinkDialogUrl = null }
     )
 
-    fun handleReaderFullscreenAwtKeyEvent(event: AwtKeyEvent): Boolean {
-        val action = event.desktopReaderKeyNavigationOrNull(fullscreen = isFullscreen) ?: return false
+    fun handleReaderAwtKeyEvent(event: AwtKeyEvent): Boolean {
         val currentSession = latestSession
+        val action = event.desktopReaderKeyNavigationOrNull(
+            fullscreen = isFullscreen,
+            rightToLeftPagination = currentSession.reader.settings.isRightToLeftPaginationEnabled()
+        ) ?: return false
         val nextSession = currentSession.reduceDesktopReaderKeyNavigation(action, readerEngine)
         if (nextSession == null) {
             if (action == DesktopReaderKeyNavigation.EXIT_FULLSCREEN && isFullscreen) {
@@ -188,6 +245,43 @@ internal fun DesktopReaderScreen(
         }
         return true
     }
+
+    fun handleReaderFullscreenAwtKeyEvent(event: AwtKeyEvent): Boolean {
+        if (latestSession.isSearchActive) {
+            if (event.id == AwtKeyEvent.KEY_PRESSED && isFullscreen && event.keyCode == AwtKeyEvent.VK_ESCAPE) {
+                setReaderFullscreen(false)
+                return true
+            }
+            return false
+        }
+        return handleReaderAwtKeyEvent(event)
+    }
+
+    fun handleReaderGlobalShortcutAwtKeyEvent(event: AwtKeyEvent): Boolean {
+        if (event.id != AwtKeyEvent.KEY_PRESSED || !event.isControlDown) return false
+        val action = when (event.keyCode) {
+            AwtKeyEvent.VK_F -> DesktopReaderKeyNavigation.SEARCH
+            AwtKeyEvent.VK_G -> DesktopReaderKeyNavigation.NEXT_SEARCH
+            else -> return false
+        }
+        val nextSession = latestSession.reduceDesktopReaderKeyNavigation(action, readerEngine) ?: return false
+        latestOnSessionChange(nextSession)
+        return true
+    }
+
+    DesktopReaderKeyDispatcherEffect(
+        enabled = externalLinkDialogUrl == null,
+        allowChromeModalWindows = true,
+        onKeyPressed = { event -> handleReaderGlobalShortcutAwtKeyEvent(event) }
+    )
+
+    DesktopReaderKeyDispatcherEffect(
+        enabled = externalLinkDialogUrl == null && !session.isSearchActive,
+        allowPanelModalWindows = true,
+        dispatchWhenOwnerWindowActive = false,
+        onKeyPressed = { event -> handleReaderAwtKeyEvent(event) }
+    )
+
     DesktopReaderFullscreenKeyEffect(
         enabled = isFullscreen && externalLinkDialogUrl == null,
         onKeyPressed = { event -> handleReaderFullscreenAwtKeyEvent(event) }
@@ -196,6 +290,9 @@ internal fun DesktopReaderScreen(
     LaunchedEffect(session.reader.settings.readingMode) {
         if (session.reader.settings.readingMode != ReaderReadingMode.PAGINATED) {
             completedMeasuredPaginationRequest = null
+            completedMeasuredPaginationPages = emptyList()
+            warmMeasuredPaginationRequest = null
+            warmMeasuredPaginationPages = emptyList()
             runningMeasuredPaginationRequest = null
         }
     }
@@ -220,15 +317,113 @@ internal fun DesktopReaderScreen(
             )
             return@LaunchedEffect
         }
-        delay(280L)
-        val settings = latestSession.reader.settings
-        if (settings.readingMode != ReaderReadingMode.PAGINATED) return@LaunchedEffect
-        if (settings.layoutSignature() != request.layoutSignature) return@LaunchedEffect
         runningMeasuredPaginationRequest = request
         try {
+            val cacheProbeStartedAt = System.nanoTime()
+            val cacheProbeSettings = latestSession.reader.settings
+            val cachedPages = if (
+                cacheProbeSettings.readingMode == ReaderReadingMode.PAGINATED &&
+                cacheProbeSettings.layoutSignature() == request.layoutSignature
+            ) {
+                withContext(Dispatchers.Default) {
+                    epubPaginationCache.loadMemory(
+                        book = session.reader.book,
+                        settings = cacheProbeSettings,
+                        viewport = request.viewport,
+                        density = request.density.density,
+                        fontScale = request.density.fontScale
+                    )
+                }
+            } else {
+                null
+            }
+            val settingsAfterCacheProbe = latestSession.reader.settings
+            if (settingsAfterCacheProbe.readingMode != ReaderReadingMode.PAGINATED) return@LaunchedEffect
+            if (settingsAfterCacheProbe.layoutSignature() != request.layoutSignature) return@LaunchedEffect
+            if (cachedPages != null) {
+                val cacheLayoutChanged = !latestSession.reader.pages.samePageLayoutAs(cachedPages)
+                logEpubPagination(
+                    "cache_warm_result book=\"${session.reader.book.title.logPreview()}\" pages=${cachedPages.size} " +
+                        "layoutChanged=$cacheLayoutChanged viewport=${request.viewport.widthPx}x${request.viewport.heightPx} " +
+                        "elapsedMs=${cacheProbeStartedAt.elapsedMillis()}"
+                )
+                if (cacheLayoutChanged) {
+                    val cacheApplySession = latestSession
+                    latestOnSessionChange(
+                        readerEngine.replacePages(
+                            state = cacheApplySession,
+                            pages = cachedPages,
+                            reflowAnchor = readerEngine.reflowAnchorFor(cacheApplySession)
+                        )
+                    )
+                }
+                completedMeasuredPaginationPages = cachedPages
+                completedMeasuredPaginationRequest = request
+                return@LaunchedEffect
+            }
+
+            val warmStartSession = latestSession
+            val warmAnchor = readerEngine.reflowAnchorFor(warmStartSession)
+            val warmChapterIndex = warmAnchor?.chapterIndex
+                ?: warmStartSession.reader.currentPage?.chapterIndex
+                ?: 0
+            val warmFirstPageIndex = warmStartSession.reader.pages.firstPageIndexForChapter(warmChapterIndex) ?: 0
+            val warmStartedAt = System.nanoTime()
+            logEpubPagination(
+                "chapter_warm_start book=\"${session.reader.book.title.logPreview()}\" chapter=$warmChapterIndex " +
+                    "firstPage=${warmFirstPageIndex + 1} viewport=${request.viewport.widthPx}x${request.viewport.heightPx}"
+            )
+            val cachedWarmChapterPages = epubPaginationCache.loadChapter(
+                book = session.reader.book,
+                settings = settingsAfterCacheProbe,
+                viewport = request.viewport,
+                chapterIndex = warmChapterIndex,
+                density = request.density.density,
+                fontScale = request.density.fontScale
+            )
+            val warmChapterPages = cachedWarmChapterPages ?: withContext(Dispatchers.Default) {
+                measuredPaginator.paginateChapterWindow(
+                    book = session.reader.book,
+                    settings = settingsAfterCacheProbe,
+                    viewport = request.viewport,
+                    chapterIndex = warmChapterIndex,
+                    firstPageIndex = warmFirstPageIndex
+                )
+            }
+            val warmPages = desktopPagesWithMeasuredChapter(
+                currentPages = warmStartSession.reader.pages,
+                chapterIndex = warmChapterIndex,
+                measuredChapterPages = warmChapterPages
+            )
+            val warmLayoutChanged = warmPages.isNotEmpty() && !warmStartSession.reader.pages.samePageLayoutAs(warmPages)
+            logEpubPagination(
+                "chapter_warm_result book=\"${session.reader.book.title.logPreview()}\" chapter=$warmChapterIndex " +
+                    "source=${if (cachedWarmChapterPages != null) "cache" else "measured"} " +
+                    "chapterPages=${warmChapterPages.size} pages=${warmPages.size} layoutChanged=$warmLayoutChanged " +
+                    "elapsedMs=${warmStartedAt.elapsedMillis()}"
+            )
+            if (warmLayoutChanged) {
+                logReaderModeSwitch(
+                    "pagination_warm_apply_dispatch requestViewport=${request.viewport.widthPx}x${request.viewport.heightPx} " +
+                        "chapter=$warmChapterIndex chapterPages=${warmChapterPages.size} currentPages=${warmStartSession.reader.pages.size}"
+                )
+                latestOnSessionChange(
+                    readerEngine.replacePages(
+                        state = warmStartSession,
+                        pages = warmPages,
+                        reflowAnchor = warmAnchor
+                    )
+                )
+                warmMeasuredPaginationPages = warmPages
+                warmMeasuredPaginationRequest = request
+            }
+
             val reflowStartSession = latestSession
             val reflowStartRequestId = reflowStartSession.navigationRequestId
             val reflowAnchor = readerEngine.reflowAnchorFor(reflowStartSession)
+            val settings = reflowStartSession.reader.settings
+            if (settings.readingMode != ReaderReadingMode.PAGINATED) return@LaunchedEffect
+            if (settings.layoutSignature() != request.layoutSignature) return@LaunchedEffect
             logEpubPagination(
                 "reflow_start book=\"${session.reader.book.title.logPreview()}\" " +
                     "viewport=${request.viewport.widthPx}x${request.viewport.heightPx} " +
@@ -237,17 +432,35 @@ internal fun DesktopReaderScreen(
                     "pageWidthSetting=${settings.pageWidth} oldPages=${reflowStartSession.reader.pages.size} " +
                     "anchorPage=${reflowAnchor?.pageIndex} anchorOffsets=${reflowAnchor?.startOffset}..${reflowAnchor?.endOffset}"
             )
-            val pages = measuredPaginator.paginate(
-                book = session.reader.book,
-                settings = settings,
-                viewport = request.viewport
-            )
+            val pages = withContext(Dispatchers.Default) {
+                measuredPaginator.paginate(
+                    book = session.reader.book,
+                    settings = settings,
+                    viewport = request.viewport,
+                    readCache = true
+                )
+            }
             val layoutChanged = pages.isNotEmpty() && !latestSession.reader.pages.samePageLayoutAs(pages)
             logEpubPagination(
                 "reflow_result book=\"${session.reader.book.title.logPreview()}\" pages=${pages.size} " +
                     "layoutChanged=$layoutChanged currentPages=${latestSession.reader.pages.size}"
             )
+            val currentVisiblePageDetails = latestSession.reader.visiblePages.map { page ->
+                "${page.pageIndex + 1}:text=${page.text.length}:blocks=${page.semanticBlocks.size}"
+            }
+            val measuredCurrentPageDetails = pages.getOrNull(latestSession.reader.currentPageIndex)
+                ?.let { page -> "${page.pageIndex + 1}:text=${page.text.length}:blocks=${page.semanticBlocks.size}" }
+                ?: "none"
+            logReaderModeSwitch(
+                "pagination_result requestViewport=${request.viewport.widthPx}x${request.viewport.heightPx} " +
+                    "measuredPages=${pages.size} currentPages=${latestSession.reader.pages.size} layoutChanged=$layoutChanged " +
+                    "currentVisible=$currentVisiblePageDetails measuredAtCurrent=$measuredCurrentPageDetails"
+            )
             if (layoutChanged) {
+                logReaderModeSwitch(
+                    "pagination_apply_dispatch requestViewport=${request.viewport.widthPx}x${request.viewport.heightPx} " +
+                        "measuredPages=${pages.size} currentPages=${latestSession.reader.pages.size}"
+                )
                 latestOnSessionChange(
                     readerEngine.replacePages(
                         state = latestSession,
@@ -258,8 +471,16 @@ internal fun DesktopReaderScreen(
                 )
             }
             if (pages.isNotEmpty()) {
+                completedMeasuredPaginationPages = pages
                 completedMeasuredPaginationRequest = request
             }
+        } catch (error: Throwable) {
+            if (error is CancellationException) throw error
+            logEpubPagination(
+                "reflow_failed book=\"${session.reader.book.title.logPreview()}\" " +
+                    "viewport=${request.viewport.widthPx}x${request.viewport.heightPx} " +
+                    "error=\"${error.message.orEmpty().logPreview(300)}\""
+            )
         } finally {
             if (runningMeasuredPaginationRequest == request) {
                 runningMeasuredPaginationRequest = null
@@ -267,16 +488,45 @@ internal fun DesktopReaderScreen(
         }
     }
 
-    val handleDesktopSelectionAction: (DesktopReaderSelectionAction, String) -> Unit = { action, text ->
+    LaunchedEffect(
+        measuredPaginationRequest,
+        completedMeasuredPaginationRequest,
+        completedMeasuredPaginationPages,
+        session.reader.pages
+    ) {
+        val request = measuredPaginationRequest ?: return@LaunchedEffect
+        val measuredPages = completedMeasuredPaginationPages
+        if (session.reader.settings.readingMode != ReaderReadingMode.PAGINATED) return@LaunchedEffect
+        if (completedMeasuredPaginationRequest != request || measuredPages.isEmpty()) return@LaunchedEffect
+        if (session.reader.pages.samePageLayoutAs(measuredPages)) return@LaunchedEffect
+        val currentVisiblePageDetails = session.reader.visiblePages.map { page ->
+            "${page.pageIndex + 1}:text=${page.text.length}:blocks=${page.semanticBlocks.size}"
+        }
+        logReaderModeSwitch(
+            "pagination_apply_pending requestViewport=${request.viewport.widthPx}x${request.viewport.heightPx} " +
+                "currentPages=${session.reader.pages.size} measuredPages=${measuredPages.size} " +
+                "currentVisible=$currentVisiblePageDetails"
+        )
+        onSessionChange(
+            readerEngine.replacePages(
+                state = session,
+                pages = measuredPages,
+                reflowAnchor = readerEngine.reflowAnchorFor(session)
+            )
+        )
+    }
+
+    val handleDesktopSelectionAction: (DesktopReaderSelectionAction, String, ReaderLocator?) -> Unit = { action, text, locator ->
         val settings = aiByokSettings.sanitized()
         when (action) {
             DesktopReaderSelectionAction.DEFINE -> {
                 if (settings.areReaderAiFeaturesAvailable) onAiAction(ReaderAiFeature.DEFINE, text)
             }
             DesktopReaderSelectionAction.SPEAK -> {
-                if (settings.isCloudTtsAvailable) onCloudTtsToggle(text)
+                if (settings.isCloudTtsAvailable) onCloudTtsToggle(text, locator)
             }
             DesktopReaderSelectionAction.SEARCH -> onExternalLookup(ReaderExternalLookupAction.SEARCH, text)
+            DesktopReaderSelectionAction.PALETTE -> Unit
         }
     }
     val nativeSelectionActions = buildSet {
@@ -285,14 +535,14 @@ internal fun DesktopReaderScreen(
         if (externalLookupAvailable) add(SharedNativeReaderSelectionAction.SEARCH)
         if (settings.isCloudTtsAvailable) add(SharedNativeReaderSelectionAction.SPEAK)
     }
-    val handleNativeSelectionAction: (SharedNativeReaderSelectionAction, String) -> Unit = { action, text ->
+    val handleNativeSelectionAction: (SharedNativeReaderSelectionAction, String, ReaderLocator?) -> Unit = { action, text, locator ->
         when (action) {
             SharedNativeReaderSelectionAction.DEFINE ->
-                handleDesktopSelectionAction(DesktopReaderSelectionAction.DEFINE, text)
+                handleDesktopSelectionAction(DesktopReaderSelectionAction.DEFINE, text, locator)
             SharedNativeReaderSelectionAction.SPEAK ->
-                handleDesktopSelectionAction(DesktopReaderSelectionAction.SPEAK, text)
+                handleDesktopSelectionAction(DesktopReaderSelectionAction.SPEAK, text, locator)
             SharedNativeReaderSelectionAction.SEARCH ->
-                handleDesktopSelectionAction(DesktopReaderSelectionAction.SEARCH, text)
+                handleDesktopSelectionAction(DesktopReaderSelectionAction.SEARCH, text, locator)
         }
     }
     val handleDesktopEpubLinkClicked: (DesktopEpubLinkClick) -> Unit = { link ->
@@ -340,6 +590,9 @@ internal fun DesktopReaderScreen(
         onFullscreenChange = ::setReaderFullscreen,
         toolbarPreferences = toolbarPreferences,
         onToolbarPreferencesChange = onToolbarPreferencesChange,
+        appThemeControls = appThemeControls,
+        customReaderThemes = customReaderThemes,
+        onCustomReaderThemesChange = onCustomReaderThemesChange,
         highlightPalette = highlightPalette,
         onHighlightPaletteChange = onHighlightPaletteChange,
         ttsReplacementPreferences = ttsReplacementPreferences,
@@ -347,7 +600,7 @@ internal fun DesktopReaderScreen(
         onTtsReplacementPreferencesChange = onTtsReplacementPreferencesChange,
         onPickCustomFont = onPickCustomFont,
         customFonts = customFonts,
-        readerExtrasState = readerExtrasState,
+        readerExtrasState = desktopReaderExtrasState,
         aiByokSettings = aiByokSettings,
         externalLookupAvailable = externalLookupAvailable,
         cloudTtsControlsAvailable = cloudTtsControlsAvailable,
@@ -359,8 +612,8 @@ internal fun DesktopReaderScreen(
         onCloudTtsPauseResume = onCloudTtsPauseResume,
         onCloudTtsStop = onCloudTtsStop,
         onCloudTtsClearCache = onCloudTtsClearCache,
+        onCloudTtsVoiceChange = onCloudTtsVoiceChange,
         onOpenAiHub = onOpenAiHub,
-        onAutoScrollChange = onAutoScrollChange,
         onDownloadReaderImage = onDownloadReaderImage,
         readerImagePreviewContent = { image, previewModifier ->
             DesktopEpubNativeImage(
@@ -369,35 +622,143 @@ internal fun DesktopReaderScreen(
             )
         },
         readerTextureDataUri = readerTextureDataUri,
+        readerTexturePreviewContent = { textureId, previewModifier ->
+            DesktopReaderTexturePreview(textureId = textureId, modifier = previewModifier)
+        },
         readerCustomTextureIds = readerCustomTextureIds,
         onImportReaderTexture = onImportReaderTexture,
         bottomChromeExtraContent = bottomChromeExtraContent,
         useDetachedChromeLayer = useDetachedChromeLayer,
         useDetachedPanelLayer = useDetachedPanelLayer
-    ) { renderPlan, onVisiblePageChanged, onHighlightSelected, onChromeActivity ->
-        Surface(
-            color = renderPlan.background,
-            shape = RoundedCornerShape(if (isFullscreen) 0.dp else 4.dp),
-            modifier = Modifier
-                .fillMaxWidth()
-                .weight(1f)
-                .clip(RoundedCornerShape(if (isFullscreen) 0.dp else 4.dp))
-                .onSizeChanged { size ->
-                    val next = ReaderViewportSpec(size.width, size.height)
-                    logReaderGap(
-                        "desktop_epub_reader_surface size=${size.width}x${size.height} " +
-                            "mode=${session.reader.settings.readingMode} " +
-                            "page=${session.reader.currentPageIndex + 1}/${session.reader.pages.size.coerceAtLeast(1)}"
+    ) { renderPlan, onVisiblePageChanged, onHighlightSelected, onOpenHighlightPaletteManager, onChromeActivity ->
+        val renderPlanModeKey = renderPlan.desktopReaderSurfaceModeKey()
+        val readerSurfaceKey = renderPlan.desktopReaderSurfaceContentKey(paginatedLayoutReady)
+        val readerModeSwitchLayoutModifier =
+            if (renderPlan is ReaderContentRenderPlan.NativePaginatedPages) {
+                Modifier.onGloballyPositioned { coordinates ->
+                    val bounds = coordinates.boundsInWindow()
+                    logReaderModeSwitch(
+                        "native_surface_layout modeKey=$renderPlanModeKey surfaceKey=$readerSurfaceKey " +
+                            "paginatedReady=$paginatedLayoutReady size=${coordinates.size.width}x${coordinates.size.height} " +
+                            "windowBounds=${bounds.left.formatLogFloat()},${bounds.top.formatLogFloat()} " +
+                            "${bounds.width.formatLogFloat()}x${bounds.height.formatLogFloat()}"
                     )
-                    if (next != readerViewport) {
-                        logEpubPagination(
-                            "viewport_changed width=${next.widthPx} height=${next.heightPx} " +
-                                "previous=${readerViewport.widthPx}x${readerViewport.heightPx}"
-                        )
-                        readerViewport = next
-                    }
                 }
+            } else {
+                Modifier
+            }
+        val readerSurfaceModifier = Modifier
+            .fillMaxWidth()
+            .weight(1f)
+            .onSizeChanged { size ->
+                val next = ReaderViewportSpec(size.width, size.height)
+                logReaderGap(
+                    "desktop_epub_reader_surface size=${size.width}x${size.height} " +
+                        "mode=${session.reader.settings.readingMode} " +
+                        "page=${session.reader.currentPageIndex + 1}/${session.reader.pages.size.coerceAtLeast(1)}"
+                )
+                logEpubCutoff(
+                    "cutoff_probe layer=desktop_surface size=${size.width}x${size.height} " +
+                        "mode=${session.reader.settings.readingMode} spread=${session.reader.settings.pageSpreadMode} " +
+                        "page=${session.reader.currentPageIndex + 1}/${session.reader.pages.size.coerceAtLeast(1)} " +
+                        "margins=${session.reader.settings.resolvedHorizontalMargin}x${session.reader.settings.resolvedVerticalMargin} " +
+                        "pageWidthSetting=${session.reader.settings.pageWidth}"
+                )
+                logWebViewLayoutDiag(
+                    "compose_reader_surface size=${size.width}x${size.height} " +
+                        "renderPlan=${if (renderPlan is ReaderContentRenderPlan.WebDocument) "web" else "native"} " +
+                        "mode=${session.reader.settings.readingMode} " +
+                        "fullscreen=$isFullscreen margins=${session.reader.settings.resolvedHorizontalMargin}x${session.reader.settings.resolvedVerticalMargin} " +
+                        "pageWidth=${session.reader.settings.pageWidth} fontSize=${session.reader.settings.fontSize} " +
+                        "lineSpacing=${session.reader.settings.lineSpacing} textAlign=${session.reader.settings.textAlign} " +
+                        "paragraphSpacing=${session.reader.settings.paragraphSpacing} imageScale=${session.reader.settings.imageScale}"
+                )
+                logDesktopReaderOpenTrace {
+                    "event=desktop_reader_surface_size bookId=\"${session.reader.book.id.logPreview(120)}\" " +
+                        "title=\"${session.reader.book.title.logPreview(120)}\" size=${size.width}x${size.height} " +
+                        "renderPlan=${renderPlan.desktopReaderSurfaceModeLabel()} mode=${session.reader.settings.readingMode} " +
+                        "page=${session.reader.currentPageIndex + 1}/${session.reader.pages.size.coerceAtLeast(1)}"
+                }
+                if (next != readerViewport) {
+                    logEpubPagination(
+                        "viewport_changed width=${next.widthPx} height=${next.heightPx} " +
+                            "previous=${readerViewport.widthPx}x${readerViewport.heightPx}"
+                    )
+                    readerViewport = next
+                }
+            }
+        LaunchedEffect(
+            renderPlanModeKey,
+            session.reader.settings.readingMode,
+            paginatedLayoutReady
         ) {
+            logReaderModeSwitch(
+                "surface_state modeKey=$renderPlanModeKey readingMode=${session.reader.settings.readingMode} " +
+                    "renderPlan=${renderPlan.desktopReaderSurfaceModeLabel()} viewport=${readerViewport.widthPx}x${readerViewport.heightPx} " +
+                    "paginatedReady=$paginatedLayoutReady runningPagination=${runningMeasuredPaginationRequest != null} " +
+                    "completedPagination=${completedMeasuredPaginationRequest != null} measuredApplied=$measuredPaginationPagesApplied " +
+                    "warmApplied=$warmMeasuredPaginationPagesApplied warmPageCount=${warmMeasuredPaginationPages.size} " +
+                    "completedMatchesRequest=${completedMeasuredPaginationRequest == measuredPaginationRequest} " +
+                    "measuredPageCount=${completedMeasuredPaginationPages.size} " +
+                    "currentPage=${session.reader.currentPageIndex + 1} " +
+                    "pageCount=${session.reader.pages.size} visiblePages=${session.reader.visiblePages.map { it.pageIndex + 1 }} " +
+                    "fullscreen=$isFullscreen surfaceKey=$readerSurfaceKey"
+            )
+            logDesktopReaderOpenTrace {
+                "event=desktop_render_plan_ready bookId=\"${session.reader.book.id.logPreview(120)}\" " +
+                    "title=\"${session.reader.book.title.logPreview(120)}\" " +
+                    "renderPlan=${renderPlan.desktopReaderSurfaceModeLabel()} mode=${session.reader.settings.readingMode} " +
+                    "viewport=${readerViewport.widthPx}x${readerViewport.heightPx} " +
+                    "page=${session.reader.currentPageIndex + 1}/${session.reader.pages.size.coerceAtLeast(1)} " +
+                    "htmlChars=${(renderPlan as? ReaderContentRenderPlan.WebDocument)?.html?.length ?: 0} " +
+                    "paginatedReady=$paginatedLayoutReady"
+            }
+            if (renderPlan is ReaderContentRenderPlan.NativePaginatedPages) {
+                cleanupRetiredDesktopWebView2InteropHosts(
+                    readerAwtWindow,
+                    "native_surface_state_ready_$paginatedLayoutReady"
+                )
+                logDesktopWebView2ModeSwitchSnapshot("surface_state_${renderPlanModeKey}_after_sweep_request")
+                readerAwtWindow.requestDesktopReaderModeSwitchRepaint(
+                    "native_surface_state_ready_$paginatedLayoutReady"
+                )
+                DesktopReaderModeSwitchProbeDelaysMillis.forEach { delayMillis ->
+                    delay(delayMillis)
+                    cleanupRetiredDesktopWebView2InteropHosts(
+                        readerAwtWindow,
+                        "native_probe_after_${delayMillis}ms_ready_$paginatedLayoutReady"
+                    )
+                    readerAwtWindow.requestDesktopReaderModeSwitchRepaint(
+                        "native_probe_after_${delayMillis}ms_ready_$paginatedLayoutReady"
+                    )
+                    logReaderModeSwitch(
+                        "native_probe_after delayMs=$delayMillis modeKey=$renderPlanModeKey " +
+                            "viewport=${readerViewport.widthPx}x${readerViewport.heightPx} " +
+                            "paginatedReady=$paginatedLayoutReady currentPage=${session.reader.currentPageIndex + 1} " +
+                            "visiblePages=${session.reader.visiblePages.map { it.pageIndex + 1 }}"
+                    )
+                    logDesktopWebView2ModeSwitchSnapshot("native_probe_after_${delayMillis}ms")
+                }
+            } else {
+                logDesktopWebView2ModeSwitchSnapshot("surface_state_$renderPlanModeKey")
+            }
+        }
+        DisposableEffect(renderPlanModeKey) {
+            logReaderModeSwitch(
+                "surface_enter modeKey=$renderPlanModeKey readingMode=${session.reader.settings.readingMode} " +
+                    "renderPlan=${renderPlan.desktopReaderSurfaceModeLabel()}"
+            )
+            logDesktopWebView2ModeSwitchSnapshot("surface_enter_$renderPlanModeKey")
+            onDispose {
+                logReaderModeSwitch(
+                    "surface_exit modeKey=$renderPlanModeKey readingMode=${session.reader.settings.readingMode} " +
+                        "renderPlan=${renderPlan.desktopReaderSurfaceModeLabel()}"
+                )
+                logDesktopWebView2ModeSwitchSnapshot("surface_exit_$renderPlanModeKey")
+            }
+        }
+        @Composable
+        fun ReaderSurfaceContent() {
             if (renderPlan is ReaderContentRenderPlan.NativePaginatedPages && !paginatedLayoutReady) {
                 DesktopEpubPaginationPreparing(
                     active = runningMeasuredPaginationRequest != null,
@@ -406,14 +767,41 @@ internal fun DesktopReaderScreen(
             } else {
                 when (renderPlan) {
                     is ReaderContentRenderPlan.WebDocument -> {
-                        if (webViewRuntimeState.initialized) {
+                        val canRenderWebDocument = desktopEpubWebViewCanRender(webViewRuntimeState)
+                        LaunchedEffect(
+                            renderPlan.html,
+                            canRenderWebDocument,
+                            webViewRuntimeState,
+                            webViewNetworkAccessEnabled
+                        ) {
+                            logDesktopWebView2(
+                                "reader_screen_web_document canRender=$canRenderWebDocument " +
+                                    "backend=${desktopEpubWebViewBackend().logName} " +
+                                    "runtimeInitialized=${webViewRuntimeState.initialized} restart=${webViewRuntimeState.restartRequired} " +
+                                    "error=${webViewRuntimeState.errorMessage != null} network=$webViewNetworkAccessEnabled " +
+                                    "htmlChars=${renderPlan.html.length} htmlHash=${renderPlan.html.hashCode()}"
+                            )
+                        }
+                        if (canRenderWebDocument) {
                             DesktopEpubWebView(
                                 html = renderPlan.html,
                                 appearanceScript = renderPlan.appearanceScript,
+                                highlightPaletteScript = renderPlan.highlightPaletteScript,
                                 navigationTarget = renderPlan.navigationTarget,
                                 highlights = renderPlan.highlights,
                                 onHighlightCreated = { highlight ->
-                                    onSessionChange(session.reduce(ReaderAction.HighlightCreated(highlight), readerEngine))
+                                    logEpubHighlightFlow(
+                                        "state_reduce_start id=${highlight.id} before=${session.highlights.size} " +
+                                            "color=${highlight.color.id} chapter=${highlight.chapterIndex} " +
+                                            "offsets=${highlight.locator.startOffset}..${highlight.locator.endOffset} " +
+                                            "page=${highlight.locator.pageIndex} textChars=${highlight.text.length}"
+                                    )
+                                    val nextSession = session.reduce(ReaderAction.HighlightCreated(highlight), readerEngine)
+                                    logEpubHighlightFlow(
+                                        "state_reduce_done id=${highlight.id} after=${nextSession.highlights.size} " +
+                                            "contains=${nextSession.highlights.any { it.id == highlight.id }}"
+                                    )
+                                    onSessionChange(nextSession)
                                 },
                                 onHighlightSelected = onHighlightSelected,
                                 isFullscreen = isFullscreen,
@@ -427,11 +815,18 @@ internal fun DesktopReaderScreen(
                                         onSessionChange(nextSession)
                                     }
                                 },
-                                onSelectionAction = handleDesktopSelectionAction,
+                                onSelectionAction = { payload ->
+                                    if (payload.action == DesktopReaderSelectionAction.PALETTE) {
+                                        onOpenHighlightPaletteManager()
+                                    } else {
+                                        handleDesktopSelectionAction(payload.action, payload.text, payload.locator)
+                                    }
+                                },
                                 onLinkClicked = handleDesktopEpubLinkClicked,
                                 onVisiblePageChanged = onVisiblePageChanged,
                                 onPointerActivity = onChromeActivity,
                                 networkAccessEnabled = webViewNetworkAccessEnabled,
+                                backgroundColor = renderPlan.background,
                                 modifier = Modifier.fillMaxSize()
                             )
                         } else {
@@ -442,36 +837,157 @@ internal fun DesktopReaderScreen(
                         }
                     }
                     is ReaderContentRenderPlan.NativePaginatedPages -> {
-                        SharedNativePaginatedReader(
-                            renderPlan = renderPlan,
-                            readerFontFamily = renderPlan.settings.toDesktopReaderFontFamily(),
-                            searchHighlight = MaterialTheme.colorScheme.tertiaryContainer.copy(alpha = 0.72f),
-                            onVisiblePageChanged = onVisiblePageChanged,
-                            enabledSelectionActions = nativeSelectionActions,
-                            onCopyText = { text -> clipboardManager.setText(AnnotatedString(text)) },
-                            onSelectionAction = handleNativeSelectionAction,
-                            onHighlightCreated = { highlight ->
-                                onSessionChange(session.reduce(ReaderAction.HighlightCreated(highlight), readerEngine))
-                            },
-                            onHighlightSelected = onHighlightSelected,
-                            onLinkClicked = { link ->
-                                handleDesktopEpubLinkClicked(link.toDesktopEpubLinkClick())
-                            },
-                            imageContent = { image, imageModifier ->
-                                DesktopEpubNativeImage(
-                                    image = image,
-                                    modifier = imageModifier
-                                )
-                            },
-                            modifier = Modifier.fillMaxSize()
-                        )
+                        LaunchedEffect(renderPlan.visiblePages, paginatedLayoutReady) {
+                            val pageDetails = renderPlan.visiblePages.joinToString(prefix = "[", postfix = "]") { page ->
+                                "${page.pageIndex + 1}:text=${page.text.length}:blocks=${page.semanticBlocks.size}"
+                            }
+                            logReaderModeSwitch(
+                                "native_reader_render paginatedReady=$paginatedLayoutReady " +
+                                    "visiblePages=${renderPlan.visiblePages.map { it.pageIndex + 1 }} " +
+                                    "pageDetails=$pageDetails " +
+                                    "background=${renderPlan.background} foreground=${renderPlan.foreground}"
+                            )
+                        }
+                        Box(
+                            modifier = Modifier
+                                .fillMaxSize()
+                                .onGloballyPositioned { coordinates ->
+                                    val bounds = coordinates.boundsInWindow()
+                                    logReaderModeSwitch(
+                                        "native_reader_content_layout size=${coordinates.size.width}x${coordinates.size.height} " +
+                                            "windowBounds=${bounds.left.formatLogFloat()},${bounds.top.formatLogFloat()} " +
+                                            "${bounds.width.formatLogFloat()}x${bounds.height.formatLogFloat()} " +
+                                            "visiblePages=${renderPlan.visiblePages.map { it.pageIndex + 1 }}"
+                                    )
+                                }
+                        ) {
+                            SharedNativePaginatedReader(
+                                renderPlan = renderPlan,
+                                readerFontFamily = renderPlan.settings.toDesktopReaderFontFamily(),
+                                searchHighlight = MaterialTheme.colorScheme.tertiaryContainer.copy(alpha = 0.72f),
+                                onVisiblePageChanged = onVisiblePageChanged,
+                                enabledSelectionActions = nativeSelectionActions,
+                                onCopyText = { text -> clipboardManager.setText(AnnotatedString(text)) },
+                                onSelectionAction = handleNativeSelectionAction,
+                                onOpenHighlightPaletteManager = onOpenHighlightPaletteManager,
+                                onHighlightCreated = { highlight ->
+                                    logDesktopHighlightMap(
+                                        "native_state_reduce_start id=${highlight.id.logPreview(80)} before=${session.highlights.size} " +
+                                            "color=${highlight.color.id} chapter=${highlight.chapterIndex} " +
+                                            "page=${highlight.locator.pageIndex} offsets=${highlight.locator.startOffset}..${highlight.locator.endOffset} " +
+                                            "block=${highlight.locator.blockIndex} char=${highlight.locator.charOffset} " +
+                                            "textChars=${highlight.text.length} cfi=\"${highlight.cfi.logPreview(160)}\""
+                                    )
+                                    val nextSession = session.reduce(ReaderAction.HighlightCreated(highlight), readerEngine)
+                                    logDesktopHighlightMap(
+                                        "native_state_reduce_done id=${highlight.id.logPreview(80)} after=${nextSession.highlights.size} " +
+                                            "contains=${nextSession.highlights.any { it.id == highlight.id }}"
+                                    )
+                                    onSessionChange(nextSession)
+                                },
+                                onHighlightSelected = onHighlightSelected,
+                                onLinkClicked = { link ->
+                                    handleDesktopEpubLinkClicked(link.toDesktopEpubLinkClick())
+                                },
+                                onReaderTap = onChromeActivity,
+                                imageContent = { image, imageModifier ->
+                                    DesktopEpubNativeImage(
+                                        image = image,
+                                        modifier = imageModifier
+                                    )
+                                },
+                                modifier = Modifier.fillMaxSize()
+                            )
+                        }
                     }
                 }
             }
         }
+
+        key(readerSurfaceKey) {
+            if (renderPlan is ReaderContentRenderPlan.WebDocument) {
+                Box(
+                    modifier = readerSurfaceModifier
+                        .fillMaxSize()
+                        .background(renderPlan.background)
+                ) {
+                    ReaderSurfaceContent()
+                }
+            } else {
+                Surface(
+                    color = renderPlan.background,
+                    shape = RoundedCornerShape(if (isFullscreen) 0.dp else 4.dp),
+                    modifier = readerSurfaceModifier
+                        .fillMaxSize()
+                        .clip(RoundedCornerShape(if (isFullscreen) 0.dp else 4.dp))
+                        .then(readerModeSwitchLayoutModifier)
+                ) {
+                    ReaderSurfaceContent()
+                }
+            }
+        }
     }
 }
 
+private fun ReaderContentRenderPlan.desktopReaderSurfaceModeKey(): String {
+    return when (this) {
+        is ReaderContentRenderPlan.WebDocument -> "desktop-reader-web"
+        is ReaderContentRenderPlan.NativePaginatedPages -> "desktop-reader-native"
+    }
+}
+
+private fun ReaderContentRenderPlan.desktopReaderSurfaceModeLabel(): String {
+    return when (this) {
+        is ReaderContentRenderPlan.WebDocument -> "web"
+        is ReaderContentRenderPlan.NativePaginatedPages -> "native"
+    }
+}
+
+private fun ReaderContentRenderPlan.desktopReaderSurfaceContentKey(paginatedLayoutReady: Boolean): String {
+    return when (this) {
+        is ReaderContentRenderPlan.WebDocument -> "desktop-reader-web"
+        is ReaderContentRenderPlan.NativePaginatedPages ->
+            "desktop-reader-native-${if (paginatedLayoutReady) "ready" else "preparing"}"
+    }
+}
+
+private fun Window?.requestDesktopReaderModeSwitchRepaint(reason: String) {
+    val targetWindow = this
+    EventQueue.invokeLater {
+        if (targetWindow == null) {
+            logReaderModeSwitch("awt_repaint_skip reason=$reason window=null")
+            return@invokeLater
+        }
+        if (!targetWindow.isDisplayable) {
+            logReaderModeSwitch(
+                "awt_repaint_skip reason=$reason window=${targetWindow.javaClass.simpleName} " +
+                    "displayable=false visible=${targetWindow.isVisible} showing=${targetWindow.isShowing} " +
+                    "size=${targetWindow.width}x${targetWindow.height}"
+            )
+            return@invokeLater
+        }
+        targetWindow.invalidate()
+        targetWindow.validate()
+        targetWindow.repaint()
+        (targetWindow as? javax.swing.RootPaneContainer)?.contentPane?.let { contentPane ->
+            contentPane.invalidate()
+            contentPane.validate()
+            contentPane.repaint()
+        }
+        logReaderModeSwitch(
+            "awt_repaint reason=$reason window=${targetWindow.javaClass.simpleName} " +
+                "visible=${targetWindow.isVisible} displayable=${targetWindow.isDisplayable} " +
+                "showing=${targetWindow.isShowing} size=${targetWindow.width}x${targetWindow.height}"
+        )
+    }
+}
+
+private val DesktopReaderModeSwitchProbeDelaysMillis = longArrayOf(120L, 350L, 900L)
+
+private fun Long.elapsedMillis(): Long {
+    return ((System.nanoTime() - this) / 1_000_000L).coerceAtLeast(0L)
+}
+
 private fun ReaderImageReference.toDesktopPreviewSemanticImage(): SemanticImage {
     return SemanticImage(
         path = source,

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopReaderTexturePreview.kt

@@ -0,0 +1,43 @@
+package com.aryan.reader.desktop
+
+import androidx.compose.foundation.Image
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.remember
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.layout.ContentScale
+import androidx.compose.ui.text.font.FontWeight
+
+@Composable
+internal fun DesktopReaderTexturePreview(
+    textureId: String,
+    modifier: Modifier = Modifier
+) {
+    val bitmap = remember(textureId) { DesktopReaderTextures.imageBitmapFor(textureId) }
+    if (bitmap != null) {
+        Image(
+            bitmap = bitmap,
+            contentDescription = null,
+            contentScale = ContentScale.Crop,
+            modifier = modifier
+        )
+    } else {
+        Box(
+            modifier = modifier
+                .fillMaxSize()
+                .background(MaterialTheme.colorScheme.surfaceVariant),
+            contentAlignment = Alignment.Center
+        ) {
+            Text(
+                "Aa",
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                fontWeight = FontWeight.Bold
+            )
+        }
+    }
+}

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopReaderTypography.kt

@@ -35,7 +35,7 @@ internal fun List<ReaderPage>.samePageLayoutAs(other: List<ReaderPage>): Boolean
             left.startOffset == right.startOffset &&
             left.endOffset == right.endOffset &&
             left.text.length == right.text.length &&
-            left.semanticBlocks.size == right.semanticBlocks.size
+            left.semanticBlocks == right.semanticBlocks
     }
 }
 

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopReaderWindowState.kt

@@ -1,19 +1,53 @@
 package com.aryan.reader.desktop
 
+import androidx.compose.ui.unit.DpSize
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.window.WindowPlacement
 import com.aryan.reader.shared.BookItem
 import com.aryan.reader.shared.ReaderCloudTtsState
 import com.aryan.reader.shared.ReaderExtrasState
 import com.aryan.reader.shared.RecapResult
 import com.aryan.reader.shared.SummarizationResult
+import com.aryan.reader.shared.reader.ReaderReadingMode
 import com.aryan.reader.shared.reader.ReaderSessionState
 import kotlinx.coroutines.Job
 
+internal const val DesktopReaderWindowDefaultWidthDp = 1120f
+internal const val DesktopReaderWindowDefaultHeightDp = 760f
+internal val DesktopReaderWindowDefaultSize = DpSize(
+    DesktopReaderWindowDefaultWidthDp.dp,
+    DesktopReaderWindowDefaultHeightDp.dp
+)
+
+internal fun DesktopWindowStateSnapshot.toReaderWindowPlacement(): WindowPlacement {
+    return when (placement) {
+        DesktopSavedWindowPlacement.FULLSCREEN -> WindowPlacement.Floating
+        else -> toWindowPlacement()
+    }
+}
+
+internal fun DesktopWindowStateSnapshot.toPersistableReaderWindowSnapshot(): DesktopWindowStateSnapshot? {
+    if (placement == DesktopSavedWindowPlacement.FULLSCREEN) return null
+    return sanitized()
+}
+
+internal fun shouldResetDesktopTextReaderWindowSurface(
+    previousMode: ReaderReadingMode,
+    currentMode: ReaderReadingMode,
+    usesNativeWebView: Boolean
+): Boolean {
+    return usesNativeWebView &&
+        previousMode == ReaderReadingMode.VERTICAL &&
+        currentMode == ReaderReadingMode.PAGINATED
+}
+
 internal data class DesktopReaderWindowState(
     val id: String,
     val opening: DesktopReaderOpening,
     val content: DesktopReaderWindowContent = DesktopReaderWindowContent.Opening,
     val focusRequestId: Long = 0L,
-    val fullscreen: Boolean = false
+    val fullscreen: Boolean = false,
+    val surfaceResetId: Long = 0L
 ) {
     val bookId: String
         get() = opening.bookId
@@ -57,7 +91,6 @@ internal sealed interface DesktopReaderWindowContent {
         val isSummaryLoading: Boolean = false,
         val isRecapLoading: Boolean = false,
         val recapProgressMessage: String? = null,
-        val showCloudTtsSettings: Boolean = false,
         val ttsJob: Job? = null
     ) : DesktopReaderWindowContent
 }

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopTtsLog.kt

@@ -1,18 +1,39 @@
 package com.aryan.reader.desktop
 
+import com.aryan.reader.shared.ReaderTtsChunk
+
 private const val DesktopTtsLogTag = "EpistemeDesktopTts"
+private const val DesktopTtsStartTraceLogTag = "EpistemeDesktopTtsStartTrace"
+private val DesktopTtsSensitiveQueryRegex = Regex("""(?i)([?&](?:key|token)=)[^&\s"]+""")
+private val DesktopTtsSensitiveLabelRegex = Regex(
+    """(?i)\b((?:geminiKey|groqKey|api[_-]?key|authorization|token)\s*[:=]\s*)[^\s,;"]+"""
+)
 
 internal fun logDesktopTts(message: String) {
     logDesktopDiagnostic(DesktopTtsLogTag) { message }
 }
 
+internal fun logDesktopTtsStartTrace(message: () -> String) {
+    logDesktopDiagnostic(DesktopTtsStartTraceLogTag, message)
+}
+
+internal fun ReaderTtsChunk?.desktopTtsStartTraceSummary(maxTextLength: Int = 120): String {
+    if (this == null) return "null"
+    return "index=$index page=${pageIndex + 1} chapter=$chapterIndex " +
+        "offsets=$startOffset..$endOffset sourceCfi=\"${sourceCfi.orEmpty().logPreview(160)}\" " +
+        "textChars=${text.length} spokenChars=${spokenText.length} " +
+        "text=\"${text.logPreview(maxTextLength)}\" spoken=\"${spokenText.logPreview(maxTextLength)}\""
+}
+
 internal fun Throwable.desktopTtsSummary(): String {
     val type = this::class.java.simpleName.ifBlank { "Throwable" }
     return "$type: ${message.orEmpty().desktopTtsPreview(220)}"
 }
 
 internal fun String.desktopTtsPreview(maxLength: Int = 120): String {
-    return replace(Regex("\\s+"), " ")
+    return replace(DesktopTtsSensitiveQueryRegex) { match -> match.groupValues[1] + "<redacted>" }
+        .replace(DesktopTtsSensitiveLabelRegex) { match -> match.groupValues[1] + "<redacted>" }
+        .replace(Regex("\\s+"), " ")
         .trim()
         .let { if (it.length <= maxLength) it else it.take(maxLength) + "..." }
         .replace("\"", "\\\"")

desktopApp/src/desktopMain/kotlin/com/aryan/reader/desktop/DesktopWindowStateStore.kt

@@ -151,5 +151,9 @@ internal class DesktopWindowStateStore(
         fun defaultWindowStateFile(): File {
             return File(desktopUserConfigRoot(), "window_state.json")
         }
+
+        fun defaultReaderWindowStateFile(): File {
+            return File(desktopUserConfigRoot(), "reader_window_state.json")
+        }
     }
 }

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopAiByokStoreTest.kt

@@ -86,6 +86,54 @@ class DesktopAiByokStoreTest {
         assertEquals(GEMINI_CLOUD_TTS_MODEL_ID, loaded.ttsModel)
     }
 
+    @Test
+    fun `save with blank key clears protected secret entry`() {
+        val settingsFile = Files.createTempDirectory("reader-ai-store-clear").resolve("ai-byok.properties")
+        val store = DesktopAiByokStore(settingsFile.toFile(), ReversibleSecretCodec)
+
+        store.save(
+            ReaderAiByokSettings(
+                geminiKey = "gemini_secret",
+                groqKey = "groq_secret",
+                modelForAll = "groq:qwen/qwen3-32b"
+            )
+        )
+        store.save(
+            ReaderAiByokSettings(
+                groqKey = "groq_secret",
+                modelForAll = "groq:qwen/qwen3-32b"
+            )
+        )
+
+        val raw = settingsFile.readText()
+        assertFalse(raw.contains("geminiKeyProtected="))
+        assertTrue(raw.contains("groqKeyProtected="))
+
+        val loaded = store.load()
+        assertEquals("", loaded.geminiKey)
+        assertEquals("groq_secret", loaded.groqKey)
+        assertEquals("groq:qwen/qwen3-32b", loaded.modelForAll)
+    }
+
+    @Test
+    fun `load ignores legacy hidden reader ai preference on desktop`() {
+        val settingsFile = Files.createTempDirectory("reader-ai-store-visible").resolve("ai-byok.properties")
+        settingsFile.writeText(
+            """
+            hideReaderAiFeatures=true
+            modelForAll=groq:qwen/qwen3-32b
+            useOneModel=true
+            """.trimIndent()
+        )
+        val store = DesktopAiByokStore(settingsFile.toFile(), ReversibleSecretCodec)
+
+        val loaded = store.load()
+
+        assertFalse(loaded.hideReaderAiFeatures)
+        assertTrue(loaded.useOneModel)
+        assertEquals("groq:qwen/qwen3-32b", loaded.modelForAll)
+    }
+
     @Test
     fun `load does not probe secure storage when settings file is missing`() {
         val settingsFile = Files.createTempDirectory("reader-ai-store-missing").resolve("ai-byok.properties")

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopAuthStoreTest.kt

@@ -0,0 +1,85 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.UserData
+import java.nio.file.Files
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFailsWith
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class DesktopAuthStoreTest {
+    @Test
+    fun `save protects refresh tokens and load restores the account`() {
+        val settingsFile = Files.createTempDirectory("reader-auth-store")
+            .resolve("auth.properties")
+            .toFile()
+        val store = DesktopAuthStore(settingsFile, ReversibleSecretCodec)
+
+        store.save(testSession())
+
+        val raw = settingsFile.readText()
+        assertFalse(raw.contains("firebase_refresh"))
+        assertFalse(raw.contains("google_refresh"))
+        assertTrue(raw.contains("firebaseRefreshTokenProtected="))
+        assertTrue(raw.contains("googleRefreshTokenProtected="))
+
+        val loaded = DesktopAuthStore(settingsFile, ReversibleSecretCodec).load()
+        assertEquals("user-1", loaded?.user?.uid)
+        assertEquals("reader@example.com", loaded?.user?.email)
+        assertEquals("firebase_refresh", loaded?.refreshToken)
+        assertEquals("google_refresh", loaded?.googleRefreshToken)
+    }
+
+    @Test
+    fun `save fails without leaving a partial account file when secure storage is unavailable`() {
+        val settingsFile = Files.createTempDirectory("reader-auth-store-unavailable")
+            .resolve("auth.properties")
+            .toFile()
+        val store = DesktopAuthStore(settingsFile, ThrowingSecretCodec)
+
+        assertFailsWith<IllegalStateException> {
+            store.save(testSession())
+        }
+        assertFalse(settingsFile.exists())
+    }
+
+    private fun testSession(): DesktopAuthSession {
+        return DesktopAuthSession(
+            user = UserData(
+                uid = "user-1",
+                displayName = "Reader",
+                photoUrl = null,
+                email = "reader@example.com"
+            ),
+            idToken = "id_token",
+            refreshToken = "firebase_refresh",
+            expiresAtEpochMillis = 123L,
+            googleAccessToken = "google_access",
+            googleRefreshToken = "google_refresh",
+            googleAccessTokenExpiresAtEpochMillis = 456L
+        )
+    }
+
+    private object ReversibleSecretCodec : DesktopSecretCodec {
+        override val isAvailable: Boolean = true
+
+        override fun protect(value: String): String {
+            return "test:" + value.reversed()
+        }
+
+        override fun unprotect(value: String): String {
+            return value.removePrefix("test:").reversed()
+        }
+    }
+
+    private object ThrowingSecretCodec : DesktopSecretCodec {
+        override val isAvailable: Boolean = false
+
+        override fun protect(value: String): String {
+            throw IllegalStateException("Secure storage unavailable")
+        }
+
+        override fun unprotect(value: String): String = ""
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopBuildProfileTest.kt

@@ -1,9 +1,8 @@
 package com.aryan.reader.desktop
 
+import com.aryan.reader.shared.GEMINI_CLOUD_TTS_MODEL_ID
 import com.aryan.reader.shared.ReaderAiByokSettings
 import com.aryan.reader.shared.SharedFeaturePolicy
-import java.io.File
-import java.nio.file.Files
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
@@ -18,9 +17,13 @@ class DesktopBuildProfileTest {
         assertEquals(EpistemeDesktopStandardAppName, profile.appName)
         assertEquals("Standard edition", profile.buildLabel)
         assertEquals(SharedFeaturePolicy.Standard, profile.featurePolicy)
+        assertTrue(profile.legalLinks.privacyPolicyUrl.endsWith("/privacy-policy.html"))
+        assertTrue(profile.legalLinks.termsUrl.endsWith("/terms-and-conditions.html"))
         assertTrue(profile.featurePolicy.networkAccess)
         assertFalse(profile.featurePolicy.byokAi)
         assertFalse(profile.byokAiAvailable)
+        assertTrue(profile.aiKeySettingsAvailable)
+        assertTrue(profile.creditBackedCloudTtsControlsAvailable)
     }
 
     @Test
@@ -31,12 +34,16 @@ class DesktopBuildProfileTest {
         assertEquals(EpistemeDesktopOssAppName, profile.appName)
         assertEquals("Offline OSS edition", profile.buildLabel)
         assertEquals(SharedFeaturePolicy.OssOffline, profile.featurePolicy)
+        assertTrue(profile.legalLinks.privacyPolicyUrl.endsWith("/oss-privacy-policy.html"))
+        assertTrue(profile.legalLinks.termsUrl.endsWith("/oss-terms-of-service.html"))
         assertFalse(profile.featurePolicy.networkAccess)
         assertFalse(profile.featurePolicy.aiAndCloud)
         assertTrue(profile.featurePolicy.byokAi)
         assertFalse(profile.byokAiAvailable)
+        assertFalse(profile.aiKeySettingsAvailable)
         assertFalse(profile.featurePolicy.opdsCatalogs)
         assertFalse(profile.featurePolicy.googleFontsDownload)
+        assertFalse(profile.creditBackedCloudTtsControlsAvailable)
     }
 
     @Test
@@ -54,23 +61,104 @@ class DesktopBuildProfileTest {
             geminiKey = "gemini_secret",
             modelForAll = "gemini:gemini-flash-lite-latest"
         )
-        val onlineOssPolicy = SharedFeaturePolicy(
-            networkAccess = true,
-            aiAndCloud = true,
-            byokAi = true
+        val onlineOssPolicy = SharedFeaturePolicy.OssOnline
+
+        val onlineOssProfile = DesktopBuildProfile(
+            flavor = "oss-online",
+            appName = "Episteme oss",
+            buildLabel = "OSS edition",
+            featurePolicy = onlineOssPolicy
         )
 
-        assertTrue(
+        assertTrue(onlineOssProfile.byokAiAvailable)
+        assertFalse(onlineOssProfile.aiKeySettingsAvailable)
+        assertEquals(settings, settings.withDesktopFeaturePolicy(onlineOssPolicy))
+        assertFalse(settings.withDesktopFeaturePolicy(SharedFeaturePolicy.Standard).hideReaderAiFeatures)
+        assertFalse(settings.withDesktopFeaturePolicy(SharedFeaturePolicy.OssOffline).hideReaderAiFeatures)
+
+        val byokCloudTtsSettings = settings.copy(
+            geminiKey = "gemini_secret",
+            ttsModel = GEMINI_CLOUD_TTS_MODEL_ID
+        )
+        val desktopByokSettings = byokCloudTtsSettings.withDesktopFeaturePolicy(onlineOssPolicy)
+        assertEquals(GEMINI_CLOUD_TTS_MODEL_ID, desktopByokSettings.ttsModel)
+        assertTrue(desktopByokSettings.isCloudTtsAvailable)
+        assertFalse(
             DesktopBuildProfile(
                 flavor = "oss-online",
                 appName = "Episteme oss",
                 buildLabel = "OSS edition",
                 featurePolicy = onlineOssPolicy
-            ).byokAiAvailable
+            ).creditBackedCloudTtsControlsAvailable
         )
-        assertEquals(settings, settings.withDesktopFeaturePolicy(onlineOssPolicy))
-        assertTrue(settings.withDesktopFeaturePolicy(SharedFeaturePolicy.Standard).hideReaderAiFeatures)
-        assertTrue(settings.withDesktopFeaturePolicy(SharedFeaturePolicy.OssOffline).hideReaderAiFeatures)
+    }
+
+    @Test
+    fun `desktop tts worker requires its own configured endpoint`() {
+        val config = DesktopCloudConfig(
+            aiWorkerUrl = "https://example.com/ai",
+            ttsWorkerUrl = "",
+            firebaseWebApiKey = "",
+            firebaseProjectId = "",
+            googleOAuthClientId = "",
+            googleOAuthClientSecret = ""
+        )
+
+        assertTrue(config.isAiWorkerConfigured)
+        assertFalse(config.isTtsWorkerConfigured)
+    }
+
+    @Test
+    fun `desktop cloud tts adapter allows byok before credit worker`() {
+        val byokAdapter = DesktopGeminiCloudTtsAdapter(
+            settingsProvider = {
+                ReaderAiByokSettings(
+                    geminiKey = "gemini_secret",
+                    ttsModel = GEMINI_CLOUD_TTS_MODEL_ID
+                )
+            },
+            networkAccess = { true },
+            workerUrlProvider = { "" }
+        )
+        val workerAdapter = DesktopGeminiCloudTtsAdapter(
+            settingsProvider = { ReaderAiByokSettings(serverBackedCloudTts = true) },
+            networkAccess = { true },
+            workerUrlProvider = { "https://example.com/tts" }
+        )
+        val unavailableAdapter = DesktopGeminiCloudTtsAdapter(
+            settingsProvider = { ReaderAiByokSettings() },
+            networkAccess = { true },
+            workerUrlProvider = { "https://example.com/tts" }
+        )
+
+        assertTrue(byokAdapter.isAvailable)
+        assertTrue(workerAdapter.isAvailable)
+        assertFalse(unavailableAdapter.isAvailable)
+    }
+
+    @Test
+    fun `desktop persisted AI settings keep Android model controls and force visibility`() {
+        val settings = ReaderAiByokSettings(
+            geminiKey = " gemini_secret ",
+            groqKey = " groq_secret ",
+            useOneModel = true,
+            modelForAll = "groq:qwen/qwen3-32b",
+            defineModel = "gemini:gemini-flash-lite-latest",
+            summarizeModel = "groq:llama-3.3-70b-versatile",
+            recapModel = "gemini:gemini-2.5-flash-lite",
+            hideReaderAiFeatures = true
+        )
+
+        val persisted = settings.toDesktopPersistableAiSettings()
+
+        assertEquals("gemini_secret", persisted.geminiKey)
+        assertEquals("groq_secret", persisted.groqKey)
+        assertTrue(persisted.useOneModel)
+        assertEquals("groq:qwen/qwen3-32b", persisted.modelForAll)
+        assertEquals("gemini:gemini-flash-lite-latest", persisted.defineModel)
+        assertEquals("groq:llama-3.3-70b-versatile", persisted.summarizeModel)
+        assertEquals("gemini:gemini-2.5-flash-lite", persisted.recapModel)
+        assertFalse(persisted.hideReaderAiFeatures)
     }
 
     @Test
@@ -84,36 +172,4 @@ class DesktopBuildProfileTest {
         assertTrue(desktopDiagnosticsFlag(" TRUE "))
     }
 
-    @Test
-    fun `bundled webview detection requires cef binaries`() {
-        val dir = Files.createTempDirectory("episteme-kcef-test").toFile()
-        try {
-            val windowsX64 = DesktopPlatform(DesktopOperatingSystem.WINDOWS, DesktopArchitecture.X64)
-            assertFalse(isBundledDesktopWebViewPresent(dir, windowsX64))
-            File(dir, "jcef.dll").writeText("jcef")
-            File(dir, "libcef.dll").writeText("cef")
-
-            assertTrue(isBundledDesktopWebViewPresent(dir, windowsX64))
-        } finally {
-            dir.deleteRecursively()
-        }
-    }
-
-    @Test
-    fun `linux bundled webview detection requires cef shared library and resources`() {
-        val dir = Files.createTempDirectory("episteme-linux-kcef-test").toFile()
-        try {
-            val linuxX64 = DesktopPlatform(DesktopOperatingSystem.LINUX, DesktopArchitecture.X64)
-            assertFalse(isBundledDesktopWebViewPresent(dir, linuxX64))
-
-            File(dir, "libcef.so").writeText("cef")
-            File(dir, "chrome-sandbox").writeText("sandbox")
-            File(dir, "icudtl.dat").writeText("icu")
-            File(dir, "locales").mkdir()
-
-            assertTrue(isBundledDesktopWebViewPresent(dir, linuxX64))
-        } finally {
-            dir.deleteRecursively()
-        }
-    }
 }

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopCloudConfigTest.kt

@@ -0,0 +1,60 @@
+package com.aryan.reader.desktop
+
+import java.util.Properties
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class DesktopCloudConfigTest {
+    @Test
+    fun `packaged resource config can enable desktop Google sign in`() {
+        val config = desktopCloudConfigFromProperties(
+            resourceProperties = properties(
+                "FIREBASE_WEB_API_KEY" to "firebase-key",
+                "FIREBASE_PROJECT_ID" to "reader-project",
+                "GOOGLE_OAUTH_CLIENT_ID" to "oauth-client",
+                "GOOGLE_OAUTH_CLIENT_SECRET" to "oauth-secret"
+            ),
+            systemProperty = { null },
+            environment = { null }
+        )
+
+        assertTrue(config.isAuthConfigured)
+        assertEquals("firebase-key", config.firebaseWebApiKey)
+        assertEquals("reader-project", config.firebaseProjectId)
+        assertEquals("oauth-client", config.googleOAuthClientId)
+        assertEquals("oauth-secret", config.googleOAuthClientSecret)
+    }
+
+    @Test
+    fun `local desktop keys override packaged resource config`() {
+        val config = desktopCloudConfigFromProperties(
+            resourceProperties = properties(
+                "FIREBASE_WEB_API_KEY" to "packaged-firebase-key",
+                "FIREBASE_PROJECT_ID" to "packaged-project",
+                "GOOGLE_OAUTH_CLIENT_ID" to "packaged-oauth-client",
+                "GOOGLE_OAUTH_CLIENT_SECRET" to "packaged-oauth-secret"
+            ),
+            localProperties = properties(
+                "DESKTOP_FIREBASE_WEB_API_KEY" to "local-firebase-key",
+                "DESKTOP_FIREBASE_PROJECT_ID" to "local-project",
+                "DESKTOP_GOOGLE_OAUTH_CLIENT_ID" to "local-oauth-client",
+                "DESKTOP_GOOGLE_OAUTH_CLIENT_SECRET" to "local-oauth-secret"
+            ),
+            systemProperty = { null },
+            environment = { null }
+        )
+
+        assertTrue(config.isAuthConfigured)
+        assertEquals("local-firebase-key", config.firebaseWebApiKey)
+        assertEquals("local-project", config.firebaseProjectId)
+        assertEquals("local-oauth-client", config.googleOAuthClientId)
+        assertEquals("local-oauth-secret", config.googleOAuthClientSecret)
+    }
+}
+
+private fun properties(vararg values: Pair<String, String>): Properties {
+    return Properties().apply {
+        values.forEach { (key, value) -> setProperty(key, value) }
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopCloudSyncMappingTest.kt

@@ -5,10 +5,16 @@ import com.aryan.reader.shared.FileType
 import com.aryan.reader.shared.HighlightColor
 import com.aryan.reader.shared.ReaderLocator
 import com.aryan.reader.shared.UserHighlight
+import com.aryan.reader.shared.pdf.SharedPdfAnnotationSerializer
+import com.aryan.reader.shared.pdf.SharedPdfBookmark
+import com.aryan.reader.shared.pdf.SharedPdfReaderViewport
+import com.aryan.reader.shared.pdf.SharedPdfRichDocument
+import com.aryan.reader.shared.pdf.SharedPdfRichTextSerializer
 import com.aryan.reader.shared.reader.ReaderBookmark
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertNotNull
+import kotlin.test.assertNull
 import kotlin.test.assertTrue
 
 class DesktopCloudSyncMappingTest {
@@ -71,6 +77,7 @@ class DesktopCloudSyncMappingTest {
         assertEquals(2, metadata.lastChapterIndex)
         assertEquals(4, metadata.lastPage)
         assertEquals(42f, metadata.progressPercentage)
+        assertEquals(1_000L, metadata.readingPositionModifiedTimestamp)
         assertTrue(assertNotNull(metadata.bookmarksJson).contains("desktop:2:30:44"))
         assertTrue(assertNotNull(metadata.highlightsJson).contains("highlighted text"))
         assertEquals(book.id, restored.id)
@@ -88,6 +95,212 @@ class DesktopCloudSyncMappingTest {
         assertEquals("desktop:2:50:64", restored.readerHighlights.single().locator.cfi)
     }
 
+    @Test
+    fun `metadata only upload can preserve remote content timestamp`() {
+        val book = BookItem(
+            id = "book-1",
+            path = null,
+            type = FileType.PDF,
+            displayName = "Book.pdf",
+            timestamp = 1_000L,
+            fileContentModifiedTimestamp = 111L
+        )
+
+        val metadata = book.toDesktopCloudBookMetadata(
+            hasAnnotations = false,
+            timestamp = 2_000L,
+            contentTimestampOverride = 999L
+        )
+
+        assertEquals(999L, metadata.fileContentModifiedTimestamp)
+    }
+
+    @Test
+    fun `metadata upload keeps reading position timestamp separate from upload timestamp`() {
+        val book = BookItem(
+            id = "book-1",
+            path = null,
+            type = FileType.PDF,
+            displayName = "Book.pdf",
+            timestamp = 1_000L,
+            lastPageIndex = 12,
+            progressPercentage = 20f,
+            readingPositionModifiedTimestamp = 1_500L
+        )
+
+        val metadata = book.toDesktopCloudBookMetadata(hasAnnotations = true, timestamp = 3_000L)
+
+        assertEquals(3_000L, metadata.lastModifiedTimestamp)
+        assertEquals(1_500L, metadata.readingPositionModifiedTimestamp)
+        assertEquals(0L, metadata.annotationModifiedTimestamp)
+        assertEquals(12, metadata.lastPage)
+    }
+
+    @Test
+    fun `metadata upload keeps annotation timestamp separate from upload timestamp`() {
+        val book = BookItem(
+            id = "book-1",
+            path = null,
+            type = FileType.PDF,
+            displayName = "Book.pdf",
+            timestamp = 1_000L
+        )
+
+        val metadata = book.toDesktopCloudBookMetadata(
+            hasAnnotations = true,
+            timestamp = 3_000L,
+            annotationModifiedTimestamp = 2_250L
+        )
+
+        assertEquals(3_000L, metadata.lastModifiedTimestamp)
+        assertEquals(2_250L, metadata.annotationModifiedTimestamp)
+        assertEquals(2_250L, metadata.effectiveCloudAnnotationModifiedTimestamp())
+    }
+
+    @Test
+    fun `annotation freshness does not fall back to book metadata timestamp`() {
+        val metadata = DesktopCloudBookMetadata(
+            bookId = "book-1",
+            type = FileType.PDF.name,
+            lastModifiedTimestamp = 5_000L,
+            hasAnnotations = true
+        )
+
+        assertEquals(0L, metadata.effectiveCloudAnnotationModifiedTimestamp())
+        assertEquals(3_000L, metadata.effectiveCloudAnnotationModifiedTimestamp(sidecarModifiedTimestamp = 3_000L))
+    }
+
+    @Test
+    fun `desktop drive file names use shared cloud content extension`() {
+        assertEquals("book-1.epub", desktopCloudBookDriveFileName("book-1", FileType.EPUB))
+        assertEquals("book-1.md", desktopCloudBookDriveFileName("book-1", FileType.MD))
+        assertEquals("book-1.mobi", desktopCloudBookDriveFileName("book-1", FileType.MOBI))
+        assertNull(desktopCloudBookDriveFileName("book-1", FileType.UNKNOWN))
+    }
+
+    @Test
+    fun `empty epub annotations upload as empty arrays`() {
+        val book = BookItem(
+            id = "book-1",
+            path = "C:/books/Book.epub",
+            type = FileType.EPUB,
+            displayName = "Book.epub",
+            timestamp = 1_000L
+        )
+
+        val metadata = book.toDesktopCloudBookMetadata(hasAnnotations = false)
+
+        assertEquals("[]", metadata.bookmarksJson)
+        assertEquals("[]", metadata.highlightsJson)
+    }
+
+    @Test
+    fun `remote pdf metadata moves stale desktop viewport to remote page`() {
+        val existing = BookItem(
+            id = "book-1",
+            path = "C:/books/Book.pdf",
+            type = FileType.PDF,
+            displayName = "Book.pdf",
+            timestamp = 1_000L,
+            lastPageIndex = 264,
+            progressPercentage = 33.125f,
+            readerPosition = ReaderLocator(pageIndex = 264),
+            pdfReaderViewport = SharedPdfReaderViewport(
+                pageIndex = 264,
+                verticalFirstPageIndex = 264,
+                verticalFirstPageScrollOffset = 120
+            )
+        )
+        val remote = DesktopCloudBookMetadata(
+            bookId = "book-1",
+            displayName = "Book.pdf",
+            type = FileType.PDF.name,
+            lastModifiedTimestamp = 2_000L,
+            lastPage = 69,
+            progressPercentage = 8.75f
+        )
+
+        val restored = remote.toDesktopBookItem(existing = existing)
+
+        assertEquals(69, restored.lastPageIndex)
+        assertEquals(8.75f, restored.progressPercentage)
+        assertNull(restored.readerPosition)
+        assertEquals(69, restored.pdfReaderViewport?.pageIndex)
+        assertEquals(69, restored.pdfReaderViewport?.verticalFirstPageIndex)
+        assertEquals(0, restored.pdfReaderViewport?.verticalFirstPageScrollOffset)
+    }
+
+    @Test
+    fun `remote metadata with older reading timestamp preserves newer local pdf position`() {
+        val existing = BookItem(
+            id = "book-1",
+            path = "C:/books/Book.pdf",
+            type = FileType.PDF,
+            displayName = "Book.pdf",
+            timestamp = 4_000L,
+            lastPageIndex = 88,
+            progressPercentage = 44f,
+            pdfReaderViewport = SharedPdfReaderViewport(pageIndex = 88, verticalFirstPageIndex = 88),
+            readingPositionModifiedTimestamp = 4_000L
+        )
+        val remote = DesktopCloudBookMetadata(
+            bookId = "book-1",
+            displayName = "Book.pdf",
+            type = FileType.PDF.name,
+            lastModifiedTimestamp = 6_000L,
+            readingPositionModifiedTimestamp = 3_000L,
+            lastPage = 12,
+            progressPercentage = 6f,
+            hasAnnotations = true
+        )
+
+        val restored = remote.toDesktopBookItem(existing = existing)
+
+        assertEquals(6_000L, restored.timestamp)
+        assertEquals(88, restored.lastPageIndex)
+        assertEquals(44f, restored.progressPercentage)
+        assertEquals(88, restored.pdfReaderViewport?.pageIndex)
+        assertEquals(4_000L, restored.readingPositionModifiedTimestamp)
+    }
+
+    @Test
+    fun `pdf metadata upload ignores stale text locator page`() {
+        val book = BookItem(
+            id = "book-1",
+            path = "C:/books/Book.pdf",
+            type = FileType.PDF,
+            displayName = "Book.pdf",
+            timestamp = 1_000L,
+            lastPageIndex = 264,
+            progressPercentage = 33.125f,
+            readerPosition = ReaderLocator(pageIndex = 69)
+        )
+
+        val metadata = book.toDesktopCloudBookMetadata(hasAnnotations = false)
+
+        assertEquals(264, metadata.lastPage)
+        assertNull(metadata.lastPositionCfi)
+    }
+
+    @Test
+    fun `comic metadata upload ignores stale text locator page`() {
+        val book = BookItem(
+            id = "book-1",
+            path = "C:/books/Book.cbt",
+            type = FileType.CBT,
+            displayName = "Book.cbt",
+            timestamp = 1_000L,
+            lastPageIndex = 42,
+            progressPercentage = 33.125f,
+            readerPosition = ReaderLocator(pageIndex = 12)
+        )
+
+        val metadata = book.toDesktopCloudBookMetadata(hasAnnotations = false)
+
+        assertEquals(42, metadata.lastPage)
+        assertNull(metadata.lastPositionCfi)
+    }
+
     @Test
     fun `remote metadata without annotation json preserves existing desktop annotations`() {
         val existingBookmark = ReaderBookmark(
@@ -127,4 +340,52 @@ class DesktopCloudSyncMappingTest {
         assertEquals(listOf(existingHighlight), restored.readerHighlights)
         assertEquals(existing.path, restored.path)
     }
+
+    @Test
+    fun `desktop pdf bookmarks map to android metadata json`() {
+        val metadataJson = desktopPdfBookmarksMetadataJson(
+            bookmarks = listOf(
+                SharedPdfBookmark(
+                    pageIndex = 3,
+                    label = "Important page",
+                    createdAt = 1_234L
+                )
+            ),
+            lastPageIndex = 9
+        )
+
+        val restored = desktopPdfBookmarksFromMetadataJson(metadataJson)
+
+        assertTrue(metadataJson.contains("\"pageIndex\""))
+        assertTrue(metadataJson.contains("\"title\""))
+        assertTrue(metadataJson.contains("\"totalPages\""))
+        assertEquals(1, restored.size)
+        assertEquals(3, restored.single().pageIndex)
+        assertEquals("Important page", restored.single().label)
+    }
+
+    @Test
+    fun `android pdf bookmark metadata keeps titles on desktop`() {
+        val restored = desktopPdfBookmarksFromMetadataJson(
+            """[{"pageIndex":2,"title":"Android bookmark","totalPages":8}]"""
+        )
+
+        assertEquals(1, restored.size)
+        assertEquals(2, restored.single().pageIndex)
+        assertEquals("Android bookmark", restored.single().label)
+    }
+
+    @Test
+    fun `empty desktop pdf annotations are not exported as cloud annotation data`() {
+        val emptyAnnotationsJson = SharedPdfAnnotationSerializer.encode(emptyList())
+
+        assertNull(desktopPdfAnnotationElementForSync(emptyAnnotationsJson))
+    }
+
+    @Test
+    fun `empty desktop pdf rich text is not exported as cloud annotation data`() {
+        val emptyRichTextJson = SharedPdfRichTextSerializer.encode(SharedPdfRichDocument())
+
+        assertNull(desktopPdfRichTextElementForSync(emptyRichTextJson))
+    }
 }

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopComicArchiveTest.kt

@@ -1,6 +1,8 @@
 package com.aryan.reader.desktop
 
 import com.aryan.reader.shared.FileType
+import org.apache.commons.compress.archivers.tar.TarArchiveEntry
+import org.apache.commons.compress.archivers.tar.TarArchiveOutputStream
 import java.io.File
 import java.nio.file.Files
 import java.util.Base64
@@ -35,11 +37,65 @@ class DesktopComicArchiveTest {
         }
     }
 
+    @Test
+    fun `closing stale comic document does not close replacement with same path`() = withTempDir { dir ->
+        val cbz = File(dir, "comic.cbz")
+        ZipOutputStream(cbz.outputStream()).use { zip ->
+            zip.putNextEntry(ZipEntry("pages/001.png"))
+            zip.write(onePixelPngBytes())
+            zip.closeEntry()
+        }
+
+        val staleDocument = DesktopPdfium.loadComic(cbz, FileType.CBZ)
+        val activeDocument = DesktopPdfium.loadComic(cbz, FileType.CBZ)
+        try {
+            staleDocument.close()
+
+            val image = DesktopPdfium.renderPageBufferedImage(activeDocument, pageIndex = 0, scale = 4f)
+
+            assertEquals(4, image.width)
+            assertEquals(4, image.height)
+        } finally {
+            staleDocument.close()
+            activeDocument.close()
+        }
+    }
+
+    @Test
+    fun `cbt archive loads image pages for pdf reader surface`() = withTempDir { dir ->
+        val cbt = File(dir, "comic.cbt")
+        TarArchiveOutputStream(cbt.outputStream()).use { tar ->
+            val bytes = onePixelPngBytes()
+            val entry = TarArchiveEntry("pages/001.png").apply {
+                size = bytes.size.toLong()
+            }
+            tar.putArchiveEntry(entry)
+            tar.write(bytes)
+            tar.closeArchiveEntry()
+            tar.finish()
+        }
+
+        val document = DesktopPdfium.loadComic(cbt, FileType.CBT)
+        try {
+            assertEquals(1, document.pageCount)
+            assertEquals(1f, document.pageSizes.single().width)
+            assertEquals(1f, document.pageSizes.single().height)
+
+            val image = DesktopPdfium.renderPageBufferedImage(document, pageIndex = 0, scale = 8f)
+
+            assertEquals(8, image.width)
+            assertEquals(8, image.height)
+        } finally {
+            document.close()
+        }
+    }
+
     @Test
     fun `desktop comic types are routed through shared reader capability map`() {
         assertTrue(DesktopComicArchive.canLoad(FileType.CBZ))
         assertTrue(DesktopComicArchive.canLoad(FileType.CBR))
         assertTrue(DesktopComicArchive.canLoad(FileType.CB7))
+        assertTrue(DesktopComicArchive.canLoad(FileType.CBT))
     }
 
     private fun withTempDir(block: (File) -> Unit) {

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopComposeInteropTest.kt

@@ -7,7 +7,7 @@ class DesktopComposeInteropTest {
     @Test
     fun `desktop enables Compose interop blending before app startup`() {
         withSystemProperty(ComposeInteropBlendingProperty, null) {
-            configureComposeSwingInterop()
+            configureComposeSwingInterop(nonNativeWebViewPlatform)
 
             assertEquals(ComposeInteropBlendingEnabled, System.getProperty(ComposeInteropBlendingProperty))
         }
@@ -16,7 +16,7 @@ class DesktopComposeInteropTest {
     @Test
     fun `desktop treats blank Compose interop blending value as unset`() {
         withSystemProperty(ComposeInteropBlendingProperty, " ") {
-            configureComposeSwingInterop()
+            configureComposeSwingInterop(nonNativeWebViewPlatform)
 
             assertEquals(ComposeInteropBlendingEnabled, System.getProperty(ComposeInteropBlendingProperty))
         }
@@ -25,7 +25,7 @@ class DesktopComposeInteropTest {
     @Test
     fun `desktop preserves explicit Compose interop blending override`() {
         withSystemProperty(ComposeInteropBlendingProperty, "false") {
-            configureComposeSwingInterop()
+            configureComposeSwingInterop(nonNativeWebViewPlatform)
 
             assertEquals("false", System.getProperty(ComposeInteropBlendingProperty))
         }
@@ -52,4 +52,11 @@ class DesktopComposeInteropTest {
             }
         }
     }
+
+    private companion object {
+        val nonNativeWebViewPlatform = DesktopPlatform(
+            os = DesktopOperatingSystem.OTHER,
+            architecture = DesktopArchitecture.X64
+        )
+    }
 }

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopEpubBridgeParsingTest.kt

@@ -0,0 +1,112 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.ReaderLocator
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class DesktopEpubBridgeParsingTest {
+    @Test
+    fun `reader position bridge keeps semantic locator fields`() {
+        val position = """
+            {
+              "pageIndex": 12,
+              "chapterIndex": 2,
+              "chapterId": "chap-2",
+              "href": "text/chapter2.xhtml",
+              "startOffset": 140,
+              "endOffset": 140,
+              "blockIndex": 9,
+              "charOffset": 140,
+              "textQuote": "quoted text",
+              "cfi": "desktop-scroll:10:100:/4/2:3"
+            }
+        """.trimIndent().readerPositionOrNull()
+
+        assertEquals(12, position?.pageIndex)
+        assertEquals(2, position?.locator?.chapterIndex)
+        assertEquals("chap-2", position?.locator?.chapterId)
+        assertEquals("text/chapter2.xhtml", position?.locator?.href)
+        assertEquals(9, position?.locator?.blockIndex)
+        assertEquals(140, position?.locator?.charOffset)
+        assertEquals("quoted text", position?.locator?.textQuote)
+        assertEquals("/4/2:3", position?.locator?.cfi)
+    }
+
+    @Test
+    fun `locator json sent to web view includes semantic position fields`() {
+        val json = ReaderLocator(
+            chapterIndex = 2,
+            chapterId = "chap-2",
+            href = "text/chapter2.xhtml",
+            pageIndex = 12,
+            startOffset = 140,
+            endOffset = 155,
+            blockIndex = 9,
+            charOffset = 140,
+            textQuote = "quoted text",
+            cfi = "/4/2:3"
+        ).toReaderLocatorJson()
+
+        assertTrue(json.contains("\"chapterId\":\"chap-2\""))
+        assertTrue(json.contains("\"href\":\"text/chapter2.xhtml\""))
+        assertTrue(json.contains("\"blockIndex\":9"))
+        assertTrue(json.contains("\"charOffset\":140"))
+    }
+
+    @Test
+    fun `selection action bridge keeps locator fields for selected tts`() {
+        val payload = """
+            {
+              "action": "speak",
+              "text": "selected text",
+              "locator": {
+                "chapterIndex": 3,
+                "chapterId": "chap-3",
+                "href": "text/chapter3.xhtml",
+                "pageIndex": 41,
+                "startOffset": 900,
+                "endOffset": 913,
+                "blockIndex": 7,
+                "charOffset": 900,
+                "textQuote": "selected text",
+                "cfi": "desktop-scroll:10:20:/4/8:12|/4/8:25"
+              }
+            }
+        """.trimIndent().readerSelectionActionOrNull()
+
+        assertEquals(DesktopReaderSelectionAction.SPEAK, payload?.action)
+        assertEquals("selected text", payload?.text)
+        assertEquals(3, payload?.locator?.chapterIndex)
+        assertEquals("chap-3", payload?.locator?.chapterId)
+        assertEquals("text/chapter3.xhtml", payload?.locator?.href)
+        assertEquals(41, payload?.locator?.pageIndex)
+        assertEquals(900, payload?.locator?.startOffset)
+        assertEquals(913, payload?.locator?.endOffset)
+        assertEquals(7, payload?.locator?.blockIndex)
+        assertEquals(900, payload?.locator?.charOffset)
+        assertEquals("selected text", payload?.locator?.textQuote)
+        assertEquals("/4/8:12|/4/8:25", payload?.locator?.cfi)
+    }
+
+    @Test
+    fun `selection action bridge parses highlight palette manager action`() {
+        val payload = """
+            {
+              "action": "palette",
+              "text": "selected text"
+            }
+        """.trimIndent().readerSelectionActionOrNull()
+
+        assertEquals(DesktopReaderSelectionAction.PALETTE, payload?.action)
+        assertEquals("selected text", payload?.text)
+    }
+
+    @Test
+    fun `desktop epub chrome tap script keeps click fallback for pointer-capable webviews`() {
+        assertTrue(DesktopEpubKeyNavigationScript.contains("var lastChromeTapNotifiedAt = 0;"))
+        assertTrue(DesktopEpubKeyNavigationScript.contains("function maybeNotifyChromeTapFromClick(event)"))
+        assertTrue(DesktopEpubKeyNavigationScript.contains("if (window.PointerEvent) {"))
+        assertTrue(DesktopEpubKeyNavigationScript.contains("maybeNotifyChromeTapFromClick(event);"))
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopEpubPaginationTest.kt

@@ -0,0 +1,119 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.reader.ReaderPage
+import com.aryan.reader.shared.reader.ReaderPageSpreadMode
+import com.aryan.reader.shared.reader.ReaderReadingMode
+import com.aryan.reader.shared.reader.ReaderSettings
+import com.aryan.reader.shared.reader.ReaderViewportSpec
+import com.aryan.reader.shared.reader.layoutSignature
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class DesktopEpubPaginationTest {
+    @Test
+    fun `measured pagination is not ready until measured pages are applied`() {
+        val request = desktopPaginationRequest()
+        val currentPages = listOf(readerPage(text = "old page"))
+        val measuredPages = listOf(readerPage(text = "measured page"))
+
+        assertFalse(
+            desktopMeasuredPaginationReady(
+                request = request,
+                completedRequest = request,
+                currentPages = currentPages,
+                measuredPages = measuredPages
+            )
+        )
+    }
+
+    @Test
+    fun `measured pagination is ready when current pages match measured pages`() {
+        val request = desktopPaginationRequest()
+        val measuredPages = listOf(readerPage(text = "measured page"))
+
+        assertTrue(
+            desktopMeasuredPaginationReady(
+                request = request,
+                completedRequest = request,
+                currentPages = measuredPages,
+                measuredPages = measuredPages
+            )
+        )
+    }
+
+    @Test
+    fun `paginated display waits for completed measured pages`() {
+        assertFalse(
+            desktopPaginatedLayoutReadyForDisplay(
+                readingMode = ReaderReadingMode.PAGINATED,
+                measuredPagesApplied = false
+            )
+        )
+        assertTrue(
+            desktopPaginatedLayoutReadyForDisplay(
+                readingMode = ReaderReadingMode.PAGINATED,
+                measuredPagesApplied = true
+            )
+        )
+        assertTrue(
+            desktopPaginatedLayoutReadyForDisplay(
+                readingMode = ReaderReadingMode.VERTICAL,
+                measuredPagesApplied = false
+            )
+        )
+    }
+
+    @Test
+    fun `measured chapter warm start replaces only that chapter and renumbers pages`() {
+        val currentPages = listOf(
+            readerPage(text = "chapter 0 page", chapterIndex = 0, pageIndex = 0),
+            readerPage(text = "chapter 1 old a", chapterIndex = 1, pageIndex = 1),
+            readerPage(text = "chapter 1 old b", chapterIndex = 1, pageIndex = 2),
+            readerPage(text = "chapter 2 page", chapterIndex = 2, pageIndex = 3)
+        )
+        val measuredChapter = listOf(
+            readerPage(text = "chapter 1 measured", chapterIndex = 1, pageIndex = 1)
+        )
+
+        val pages = desktopPagesWithMeasuredChapter(
+            currentPages = currentPages,
+            chapterIndex = 1,
+            measuredChapterPages = measuredChapter
+        )
+
+        assertEquals(listOf(0, 1, 2), pages.map { it.pageIndex })
+        assertEquals(listOf(0, 1, 2), pages.map { it.chapterIndex })
+        assertEquals("chapter 1 measured", pages[1].text)
+    }
+
+    private fun desktopPaginationRequest(): DesktopEpubPaginationRequest {
+        return DesktopEpubPaginationRequest(
+            bookId = "book",
+            chapterSignature = 1,
+            layoutSignature = ReaderSettings(
+                readingMode = ReaderReadingMode.PAGINATED,
+                pageSpreadMode = ReaderPageSpreadMode.SINGLE
+            ).layoutSignature(),
+            viewport = ReaderViewportSpec(widthPx = 1200, heightPx = 900),
+            density = DesktopEpubPaginationDensity(density = 1f, fontScale = 1f),
+            cacheGeneration = 0
+        )
+    }
+
+    private fun readerPage(
+        text: String,
+        chapterIndex: Int = 0,
+        pageIndex: Int = 0
+    ): ReaderPage {
+        return ReaderPage(
+            pageIndex = pageIndex,
+            chapterIndex = chapterIndex,
+            chapterTitle = "Chapter",
+            text = text,
+            startOffset = 0,
+            endOffset = text.length
+        )
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopFeatureNoticePlacementTest.kt

@@ -0,0 +1,24 @@
+package com.aryan.reader.desktop
+
+import kotlin.test.Test
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class DesktopFeatureNoticePlacementTest {
+    @Test
+    fun `main notice renders only in the main window`() {
+        val placement = desktopFeatureNoticePlacement(readerWindowId = null)
+
+        assertTrue(placement.rendersInMainWindow())
+        assertFalse(placement.rendersInReaderWindow("reader-1"))
+    }
+
+    @Test
+    fun `reader notice renders only in the matching reader window`() {
+        val placement = desktopFeatureNoticePlacement(readerWindowId = "reader-1")
+
+        assertFalse(placement.rendersInMainWindow())
+        assertTrue(placement.rendersInReaderWindow("reader-1"))
+        assertFalse(placement.rendersInReaderWindow("reader-2"))
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopLibraryDatabaseTest.kt

@@ -0,0 +1,55 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.SharedLibrarySnapshot
+import com.aryan.reader.shared.SharedLibrarySnapshotJson
+import java.nio.file.Files
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class DesktopLibraryDatabaseTest {
+    @Test
+    fun `save writes readable library and backup snapshots`() {
+        val databaseFile = Files.createTempDirectory("reader-library-db")
+            .resolve("library.json")
+            .toFile()
+        val database = DesktopLibraryDatabase(databaseFile)
+        val snapshot = SharedLibrarySnapshot(
+            recentFilesLimit = 37,
+            openTabIds = listOf("book-a"),
+            activeTabBookId = "book-a"
+        )
+
+        database.save(snapshot)
+
+        val loaded = database.load()
+        assertEquals(37, loaded.recentFilesLimit)
+        assertEquals(listOf("book-a"), loaded.openTabIds)
+        assertEquals("book-a", loaded.activeTabBookId)
+        assertTrue(databaseFile.isFile)
+        assertTrue(databaseFile.parentFile.resolve("library.json.bak").isFile)
+    }
+
+    @Test
+    fun `load falls back to backup when primary library is corrupt`() {
+        val databaseFile = Files.createTempDirectory("reader-library-db-corrupt")
+            .resolve("library.json")
+            .toFile()
+        val backupSnapshot = SharedLibrarySnapshot(
+            recentFilesLimit = 19,
+            openTabIds = listOf("backup-book"),
+            activeTabBookId = "backup-book"
+        )
+        databaseFile.parentFile.mkdirs()
+        databaseFile.writeText("""{"books":[""")
+        databaseFile.parentFile
+            .resolve("library.json.bak")
+            .writeText(SharedLibrarySnapshotJson.encode(backupSnapshot))
+
+        val loaded = DesktopLibraryDatabase(databaseFile).load()
+
+        assertEquals(19, loaded.recentFilesLimit)
+        assertEquals(listOf("backup-book"), loaded.openTabIds)
+        assertEquals("backup-book", loaded.activeTabBookId)
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopLocalFolderSyncTest.kt

@@ -11,8 +11,37 @@ import java.nio.file.Files
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertNull
+import kotlin.test.assertTrue
 
 class DesktopLocalFolderSyncTest {
+    @Test
+    fun `target folder sync imports files before desktop metadata extraction`() {
+        val root = Files.createTempDirectory("reader-desktop-folder-sync").toFile()
+        try {
+            val bookFile = File(root, "Notes.txt").apply { writeText("Notes") }
+
+            val result = DesktopLocalFolderSync.sync(
+                state = SharedReaderScreenState(),
+                shelfRefs = emptyList(),
+                targetFolder = root,
+                nowMillis = 3_000L,
+                extractMetadata = false
+            )
+
+            val syncedBook = result.state.rawLibraryBooks.single()
+            assertEquals("local_Notes.txt", syncedBook.id)
+            assertEquals(bookFile.absolutePath, syncedBook.path)
+            assertEquals(root.absolutePath, syncedBook.sourceFolder)
+            assertEquals(listOf(root.absolutePath), result.processedFolderUris)
+            assertEquals(1, result.state.syncedFolders.size)
+            assertEquals(1, result.stats.newBooks)
+            assertEquals(0, result.metadataStats.updatedBooks)
+            assertNull(syncedBook.coverImagePath)
+        } finally {
+            root.deleteRecursively()
+        }
+    }
+
     @Test
     fun `metadata-only sync imports sidecar metadata without scanning physical files`() {
         val root = Files.createTempDirectory("reader-desktop-folder-sync").toFile()
@@ -61,6 +90,40 @@ class DesktopLocalFolderSyncTest {
             assertEquals(0, result.stats.newBooks)
             assertEquals(0, result.stats.removedBooks)
             assertEquals(1, result.stats.remoteMetadataUpdates)
+            assertTrue(result.processedFolderUris.contains(root.absolutePath))
+        } finally {
+            root.deleteRecursively()
+        }
+    }
+
+    @Test
+    fun `disabled folder is not scanned or written`() {
+        val root = Files.createTempDirectory("reader-desktop-folder-sync").toFile()
+        try {
+            File(root, "Notes.txt").writeText("Notes")
+            val existingBook = BookItem(
+                id = "local_Existing.pdf",
+                path = File(root, "Existing.pdf").absolutePath,
+                type = FileType.PDF,
+                displayName = "Existing.pdf",
+                timestamp = 100L,
+                progressPercentage = 50f,
+                sourceFolder = root.absolutePath
+            )
+
+            val result = DesktopLocalFolderSync.sync(
+                state = SharedReaderScreenState(
+                    rawLibraryBooks = listOf(existingBook),
+                    syncedFolders = listOf(syncedFolder(root).copy(localSyncEnabled = false))
+                ),
+                shelfRefs = emptyList(),
+                nowMillis = 3_000L
+            )
+
+            assertEquals(listOf(existingBook), result.state.rawLibraryBooks)
+            assertTrue(result.processedFolderUris.isEmpty())
+            assertEquals(0, result.stats.newBooks)
+            assertTrue(!File(root, LOCAL_FOLDER_SYNC_DATA_DIR).exists())
         } finally {
             root.deleteRecursively()
         }

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopPaidAiUsageTest.kt

@@ -0,0 +1,15 @@
+package com.aryan.reader.desktop
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class DesktopPaidAiUsageTest {
+    @Test
+    fun `desktop paid AI usage applies an optimistic integer credit decrement`() {
+        assertEquals(9, desktopCreditsAfterPaidAiUsage(currentCredits = 10, cost = 1.0))
+        assertEquals(7, desktopCreditsAfterPaidAiUsage(currentCredits = 10, cost = 2.2))
+        assertEquals(10, desktopCreditsAfterPaidAiUsage(currentCredits = 10, cost = 0.0))
+        assertEquals(10, desktopCreditsAfterPaidAiUsage(currentCredits = 10, cost = null))
+        assertEquals(0, desktopCreditsAfterPaidAiUsage(currentCredits = 1, cost = 4.0))
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopPdfNavigationSidebarTest.kt

@@ -0,0 +1,56 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.pdf.PdfAnnotationKind
+import com.aryan.reader.shared.pdf.PdfInkTool
+import com.aryan.reader.shared.pdf.SharedPdfAnnotation
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class DesktopPdfNavigationSidebarTest {
+    @Test
+    fun `sidebar highlights exclude ink and text annotations`() {
+        val result = desktopPdfSidebarHighlights(
+            listOf(
+                annotation(id = "ink", pageIndex = 0, kind = PdfAnnotationKind.INK, createdAt = 1L),
+                annotation(id = "later-highlight", pageIndex = 2, kind = PdfAnnotationKind.HIGHLIGHT, createdAt = 4L),
+                annotation(id = "text", pageIndex = 1, kind = PdfAnnotationKind.TEXT, createdAt = 1L),
+                annotation(
+                    id = "first-same-page-highlight",
+                    pageIndex = 1,
+                    kind = PdfAnnotationKind.HIGHLIGHT,
+                    createdAt = 3L
+                ),
+                annotation(
+                    id = "second-same-page-highlight",
+                    pageIndex = 1,
+                    kind = PdfAnnotationKind.HIGHLIGHT,
+                    createdAt = 2L
+                )
+            )
+        )
+
+        assertEquals(
+            listOf("first-same-page-highlight", "second-same-page-highlight", "later-highlight"),
+            result.map { it.id }
+        )
+        assertTrue(result.all { it.kind == PdfAnnotationKind.HIGHLIGHT })
+    }
+
+    private fun annotation(
+        id: String,
+        pageIndex: Int,
+        kind: PdfAnnotationKind,
+        createdAt: Long
+    ): SharedPdfAnnotation {
+        return SharedPdfAnnotation(
+            id = id,
+            pageIndex = pageIndex,
+            kind = kind,
+            tool = if (kind == PdfAnnotationKind.TEXT) PdfInkTool.TEXT else PdfInkTool.HIGHLIGHTER,
+            text = "selected text",
+            colorArgb = 0x55FFEB3B,
+            createdAt = createdAt
+        )
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopPdfReflowTest.kt

@@ -4,6 +4,7 @@ import com.aryan.reader.shared.BookItem
 import com.aryan.reader.shared.FileType
 import com.aryan.reader.shared.SharedLibraryStateProjector
 import com.aryan.reader.shared.SharedReaderScreenState
+import com.aryan.reader.shared.ui.toNonReaderLibraryOrganizationModel
 import java.io.File
 import kotlin.test.Test
 import kotlin.test.assertEquals
@@ -85,6 +86,7 @@ class DesktopPdfReflowTest {
         assertEquals(listOf(source.id), projected.libraryBooks.map { it.id })
         assertTrue(projected.rawLibraryBooks.any { it.id == reflow.id })
         assertTrue(projected.recentBooks.none { it.id == reflow.id })
+        assertEquals(1, projected.toNonReaderLibraryOrganizationModel().allBooksCount)
         assertEquals(listOf(reflow.id), projected.openTabIds)
         assertEquals(reflow.id, projected.activeTabBookId)
     }

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopPdfScrubbingTest.kt

@@ -0,0 +1,60 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.PdfDisplayMode
+import com.aryan.reader.shared.reader.ReaderPageSpreadMode
+import com.aryan.reader.shared.reader.ReaderSettings
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class DesktopPdfScrubbingTest {
+    @Test
+    fun `scrub target clamps to valid page range`() {
+        val settings = ReaderSettings()
+
+        assertEquals(
+            0,
+            desktopPdfPageScrubTarget(
+                value = -10f,
+                pageCount = 6,
+                displayMode = PdfDisplayMode.VERTICAL_SCROLL,
+                settings = settings
+            )
+        )
+        assertEquals(
+            5,
+            desktopPdfPageScrubTarget(
+                value = 99f,
+                pageCount = 6,
+                displayMode = PdfDisplayMode.VERTICAL_SCROLL,
+                settings = settings
+            )
+        )
+    }
+
+    @Test
+    fun `paginated scrub target normalizes to spread start`() {
+        val settings = ReaderSettings(pageSpreadMode = ReaderPageSpreadMode.TWO_PAGE)
+
+        assertEquals(
+            2,
+            desktopPdfPageScrubTarget(
+                value = 3f,
+                pageCount = 8,
+                displayMode = PdfDisplayMode.PAGINATION,
+                settings = settings
+            )
+        )
+    }
+
+    @Test
+    fun `scrub commit prefers preview before page state catches up`() {
+        assertEquals(
+            7,
+            desktopPdfPageScrubCommitTarget(
+                previewPage = 7,
+                currentPage = 2,
+                pageCount = 10
+            )
+        )
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopPdfSidecarsTest.kt

@@ -0,0 +1,16 @@
+package com.aryan.reader.desktop
+
+import kotlin.test.Test
+import kotlin.test.assertNotEquals
+import kotlin.test.assertTrue
+
+class DesktopPdfSidecarsTest {
+    @Test
+    fun `pdf sidecar keys avoid String hashCode collisions`() {
+        val first = desktopPdfDocumentKey("C:/Books/Aa.pdf")
+        val second = desktopPdfDocumentKey("C:/Books/BB.pdf")
+
+        assertTrue("C:/Books/Aa.pdf".hashCode() == "C:/Books/BB.pdf".hashCode())
+        assertNotEquals(first, second)
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopPdfTextHighlightStateTest.kt

@@ -0,0 +1,69 @@
+package com.aryan.reader.desktop
+
+import com.aryan.reader.shared.pdf.PdfAnnotationKind
+import com.aryan.reader.shared.pdf.PdfInkTool
+import com.aryan.reader.shared.pdf.SharedPdfAnnotation
+import com.aryan.reader.shared.pdf.SharedPdfReaderAction
+import com.aryan.reader.shared.pdf.SharedPdfReaderState
+import com.aryan.reader.shared.pdf.reduce
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+
+class DesktopPdfTextHighlightStateTest {
+    @Test
+    fun `text selection highlight keeps chosen text selection mode after creation`() {
+        val annotation = textSelectionHighlight()
+        val state = SharedPdfReaderState.initial(pageCount = 1)
+            .reduce(SharedPdfReaderAction.TextSelectionModeChanged(true))
+
+        val next = state.withDesktopPdfTextSelectionHighlightAdded(annotation)
+
+        assertEquals(listOf(annotation), next.annotations)
+        assertTrue(next.isTextSelectionMode)
+        assertEquals(PdfInkTool.NONE, next.selectedTool)
+        assertNull(next.selectedAnnotationId)
+    }
+
+    @Test
+    fun `dismissing selected text highlight sheet keeps chosen text selection mode`() {
+        val annotation = textSelectionHighlight()
+        val state = SharedPdfReaderState.initial(pageCount = 1)
+            .reduce(SharedPdfReaderAction.TextSelectionModeChanged(true))
+            .copy(annotations = listOf(annotation), selectedAnnotationId = annotation.id)
+
+        val next = state.withDesktopPdfTextHighlightSheetDismissed()
+
+        assertTrue(next.isTextSelectionMode)
+        assertEquals(PdfInkTool.NONE, next.selectedTool)
+        assertNull(next.selectedAnnotationId)
+    }
+
+    @Test
+    fun `dismissing non text highlight annotation keeps text selection mode unchanged`() {
+        val annotation = textSelectionHighlight().copy(rangeStartIndex = null, rangeEndIndex = null)
+        val state = SharedPdfReaderState.initial(pageCount = 1)
+            .reduce(SharedPdfReaderAction.TextSelectionModeChanged(true))
+            .copy(annotations = listOf(annotation), selectedAnnotationId = annotation.id)
+
+        val next = state.withDesktopPdfTextHighlightSheetDismissed()
+
+        assertTrue(next.isTextSelectionMode)
+        assertNull(next.selectedAnnotationId)
+    }
+
+    private fun textSelectionHighlight(): SharedPdfAnnotation {
+        return SharedPdfAnnotation(
+            id = "highlight-1",
+            pageIndex = 0,
+            kind = PdfAnnotationKind.HIGHLIGHT,
+            tool = PdfInkTool.HIGHLIGHTER,
+            text = "selected text",
+            colorArgb = 0x55FFEB3B,
+            rangeStartIndex = 1,
+            rangeEndIndex = 12,
+            createdAt = 1L
+        )
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopPdfThemeTest.kt

@@ -9,9 +9,10 @@ import kotlin.test.assertEquals
 
 class DesktopPdfThemeTest {
     @Test
-    fun `desktop pdf defaults to vertical display mode`() {
-        assertEquals(PdfDisplayMode.VERTICAL_SCROLL, DesktopDefaultPdfDisplayMode)
+    fun `desktop pdf defaults to paginated display mode`() {
+        assertEquals(PdfDisplayMode.PAGINATION, DesktopDefaultPdfDisplayMode)
         assertEquals(8.dp, DesktopDefaultPdfVerticalPageGap)
+        assertEquals(18.dp, DesktopDefaultPdfSpreadPageGap)
     }
 
     @Test
@@ -49,4 +50,35 @@ class DesktopPdfThemeTest {
             )
         )
     }
+
+    @Test
+    fun `pagination viewport uses app theme color outside pages`() {
+        val pageBackground = Color.Black
+        val appBackground = Color(0xFFE2E2E2)
+
+        assertEquals(
+            appBackground,
+            desktopPdfViewportBackgroundColor(
+                displayMode = PdfDisplayMode.PAGINATION,
+                pageBackgroundColor = pageBackground,
+                appBackgroundColor = appBackground,
+                isVerticalPageGapVisible = false
+            )
+        )
+        assertEquals(
+            appBackground,
+            desktopPdfViewportBackgroundColor(
+                displayMode = PdfDisplayMode.PAGINATION,
+                pageBackgroundColor = pageBackground,
+                appBackgroundColor = appBackground,
+                isVerticalPageGapVisible = true
+            )
+        )
+    }
+
+    @Test
+    fun `spread page gap follows pdf page gap visibility setting`() {
+        assertEquals(18.dp, desktopPdfSpreadPageGapDp(isPageGapVisible = true))
+        assertEquals(0.dp, desktopPdfSpreadPageGapDp(isPageGapVisible = false))
+    }
 }

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopPlatformPathsTest.kt

@@ -10,7 +10,6 @@ class DesktopPlatformPathsTest {
 
         assertEquals(DesktopOperatingSystem.LINUX, platform.os)
         assertEquals(DesktopArchitecture.X64, platform.architecture)
-        assertEquals("kcef-bundle-linux-x64", platform.kcefBundleDirectoryName)
         assertEquals("linux-x64-v8", platform.pdfiumDirectoryName)
         assertEquals("lib", platform.pdfiumLibraryDirectoryName)
         assertEquals("libpdfium.so", platform.pdfiumLibraryFileName)
@@ -22,7 +21,6 @@ class DesktopPlatformPathsTest {
 
         assertEquals(DesktopOperatingSystem.WINDOWS, platform.os)
         assertEquals(DesktopArchitecture.X64, platform.architecture)
-        assertEquals("kcef-bundle", platform.kcefBundleDirectoryName)
         assertEquals("win-x64-v8", platform.pdfiumDirectoryName)
         assertEquals("bin", platform.pdfiumLibraryDirectoryName)
         assertEquals("pdfium.dll", platform.pdfiumLibraryFileName)

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopReaderDefaultsTest.kt

@@ -5,13 +5,17 @@ import androidx.compose.ui.unit.IntOffset
 import androidx.compose.ui.unit.IntSize
 import com.aryan.reader.shared.BookItem
 import com.aryan.reader.shared.FileType
+import com.aryan.reader.shared.PdfDisplayMode
 import com.aryan.reader.shared.ReaderPlatform
 import com.aryan.reader.shared.SharedFileCapabilities
+import com.aryan.reader.shared.SharedLibrarySnapshot
 import com.aryan.reader.shared.pdf.PdfZoomSpec
+import com.aryan.reader.shared.reader.ReaderPageSpreadMode
 import com.aryan.reader.shared.reader.ReaderReadingMode
 import com.aryan.reader.shared.reader.ReaderSettings
 import kotlin.test.Test
 import kotlin.test.assertEquals
+import kotlin.test.assertFalse
 import kotlin.test.assertTrue
 
 class DesktopReaderDefaultsTest {
@@ -42,6 +46,96 @@ class DesktopReaderDefaultsTest {
         assertEquals(local, resolvedDesktopReaderSettings(book, defaults))
     }
 
+    @Test
+    fun `desktop library defaults migrate untouched reader defaults to two page pagination`() {
+        val migrated = SharedLibrarySnapshot().withDesktopDefaults()
+
+        assertEquals(DesktopReaderDefaultsVersion, migrated.desktopReaderDefaultsVersion)
+        assertEquals(ReaderReadingMode.PAGINATED, migrated.readerDefaultSettings.readingMode)
+        assertEquals(ReaderPageSpreadMode.TWO_PAGE, migrated.readerDefaultSettings.pageSpreadMode)
+        assertEquals(ReaderReadingMode.PAGINATED, migrated.pdfReaderDefaultSettings.readingMode)
+        assertEquals(ReaderPageSpreadMode.TWO_PAGE, migrated.pdfReaderDefaultSettings.pageSpreadMode)
+        assertEquals("no_theme", migrated.pdfReaderDefaultSettings.themeId)
+    }
+
+    @Test
+    fun `desktop reader settings engines are separated by shared reader surface`() {
+        assertEquals(DesktopReaderSettingsEngine.TEXT, FileType.EPUB.desktopReaderSettingsEngine())
+        assertEquals(DesktopReaderSettingsEngine.TEXT, FileType.MOBI.desktopReaderSettingsEngine())
+        assertEquals(DesktopReaderSettingsEngine.TEXT, FileType.DOCX.desktopReaderSettingsEngine())
+        assertEquals(DesktopReaderSettingsEngine.PDF, FileType.PDF.desktopReaderSettingsEngine())
+        assertEquals(DesktopReaderSettingsEngine.PDF, FileType.CBZ.desktopReaderSettingsEngine())
+        assertEquals(DesktopReaderSettingsEngine.PDF, FileType.CBT.desktopReaderSettingsEngine())
+        assertEquals(DesktopReaderSettingsEngine.PDF, FileType.PPTX.desktopReaderSettingsEngine())
+    }
+
+    @Test
+    fun `desktop engine settings update only matching reader family books`() {
+        val textSettings = ReaderSettings(themeId = "sepia", readingMode = ReaderReadingMode.PAGINATED)
+        val pdfSettings = ReaderSettings(themeId = "reverse", readingMode = ReaderReadingMode.PAGINATED)
+        val books = listOf(
+            bookItem("epub"),
+            bookItem("mobi").copy(path = "C:/Books/mobi.mobi", type = FileType.MOBI, displayName = "mobi.mobi"),
+            bookItem("pdf").copy(path = "C:/Books/pdf.pdf", type = FileType.PDF, displayName = "pdf.pdf")
+        )
+
+        val withTextDefaults = books.withDesktopReaderEngineSettings(DesktopReaderSettingsEngine.TEXT, textSettings)
+        assertEquals(textSettings, withTextDefaults[0].readerSettings)
+        assertEquals(textSettings, withTextDefaults[1].readerSettings)
+        assertEquals(null, withTextDefaults[2].readerSettings)
+
+        val withPdfDefaults = withTextDefaults.withDesktopReaderEngineSettings(DesktopReaderSettingsEngine.PDF, pdfSettings)
+        assertEquals(textSettings, withPdfDefaults[0].readerSettings)
+        assertEquals(textSettings, withPdfDefaults[1].readerSettings)
+        assertEquals(pdfSettings, withPdfDefaults[2].readerSettings)
+    }
+
+    @Test
+    fun `desktop pdf display mode is carried by pdf reader settings`() {
+        assertEquals(PdfDisplayMode.PAGINATION, DesktopDefaultPdfDisplayMode)
+        assertEquals(PdfDisplayMode.PAGINATION, DesktopDefaultPdfReaderSettings.toDesktopPdfDisplayMode())
+        assertEquals(
+            PdfDisplayMode.VERTICAL_SCROLL,
+            ReaderSettings(readingMode = ReaderReadingMode.VERTICAL).toDesktopPdfDisplayMode()
+        )
+    }
+
+    @Test
+    fun `desktop pdf initial page is normalized before paginated spread display`() {
+        val spreadSettings = ReaderSettings(
+            readingMode = ReaderReadingMode.PAGINATED,
+            pageSpreadMode = ReaderPageSpreadMode.TWO_PAGE
+        )
+
+        assertEquals(
+            2,
+            desktopPdfInitialPageIndex(
+                requestedPageIndex = 3,
+                pageCount = 10,
+                displayMode = PdfDisplayMode.PAGINATION,
+                settings = spreadSettings
+            )
+        )
+        assertEquals(
+            3,
+            desktopPdfInitialPageIndex(
+                requestedPageIndex = 3,
+                pageCount = 10,
+                displayMode = PdfDisplayMode.VERTICAL_SCROLL,
+                settings = spreadSettings
+            )
+        )
+        assertEquals(
+            3,
+            desktopPdfInitialPageIndex(
+                requestedPageIndex = 3,
+                pageCount = 10,
+                displayMode = PdfDisplayMode.PAGINATION,
+                settings = spreadSettings.copy(pageSpreadMode = ReaderPageSpreadMode.SINGLE)
+            )
+        )
+    }
+
     @Test
     fun `desktop pdf zoom allows deeper page magnification`() {
         val sharedDefaultMax = PdfZoomSpec().max
@@ -65,6 +159,26 @@ class DesktopReaderDefaultsTest {
         assertEquals(0.5f, desktopPdfZoomTarget(currentZoom = 0.6f, zoomSpec = zoomSpec, factor = 0.1f))
     }
 
+    @Test
+    fun `desktop pdf page navigation commits pending zoom preview position`() {
+        val preview = DesktopPdfZoomPreview(
+            baseZoom = 1f,
+            zoom = 2f,
+            anchor = Offset(100f, 80f),
+            displayMode = PdfDisplayMode.PAGINATION,
+            pageIndex = 0
+        )
+        val snapshot = desktopPdfNavigationZoomSnapshot(
+            preview = preview,
+            currentHorizontalScroll = 40,
+            currentVerticalScroll = 20
+        ) ?: error("Expected navigation zoom snapshot")
+
+        assertEquals(2f, snapshot.zoom)
+        assertEquals(180, snapshot.horizontalScroll)
+        assertEquals(120, snapshot.verticalScroll)
+    }
+
     @Test
     fun `desktop paginated pdf page changes avoid high resolution first render`() {
         assertEquals(
@@ -93,6 +207,247 @@ class DesktopReaderDefaultsTest {
         )
     }
 
+    @Test
+    fun `desktop pdf only displays renders for the requested page`() {
+        assertTrue(desktopPdfRenderBelongsToPage(renderedPageIndex = 0, requestedPageIndex = 0))
+        assertFalse(desktopPdfRenderBelongsToPage(renderedPageIndex = null, requestedPageIndex = 0))
+        assertFalse(desktopPdfRenderBelongsToPage(renderedPageIndex = 1, requestedPageIndex = 0))
+    }
+
+    @Test
+    fun `desktop pdf render scale rerenders only for missing or lower quality renders`() {
+        assertTrue(desktopPdfRenderScaleNeedsUpgrade(renderedScale = null, requestedScale = 1f))
+        assertTrue(desktopPdfRenderScaleNeedsUpgrade(renderedScale = 1f, requestedScale = 1.02f))
+        assertTrue(desktopPdfRenderScaleNeedsUpgrade(renderedScale = Float.NaN, requestedScale = 1f))
+        assertFalse(desktopPdfRenderScaleNeedsUpgrade(renderedScale = 1f, requestedScale = 1.005f))
+        assertFalse(desktopPdfRenderScaleNeedsUpgrade(renderedScale = 2f, requestedScale = 1f))
+        assertFalse(desktopPdfRenderScaleNeedsUpgrade(renderedScale = 1f, requestedScale = Float.NaN))
+    }
+
+    @Test
+    fun `desktop pdf spread zoom anchors to page under cursor`() {
+        val visiblePages = listOf(199, 200)
+        val pageRoots = mapOf(
+            199 to Offset(424f, 30f),
+            200 to Offset(972f, 30f)
+        )
+        val pageSizes = mapOf(
+            199 to IntSize(525, 693),
+            200 to IntSize(525, 693)
+        )
+
+        assertEquals(
+            200,
+            desktopPdfSpreadZoomAnchorPageIndex(
+                viewportRootOffset = Offset.Zero,
+                anchor = Offset(1048.75f, 465f),
+                visiblePageIndices = visiblePages,
+                pageRootOffsets = pageRoots,
+                pageSizes = pageSizes,
+                fallbackPageIndex = 199
+            )
+        )
+        assertEquals(
+            199,
+            desktopPdfSpreadZoomAnchorPageIndex(
+                viewportRootOffset = Offset.Zero,
+                anchor = Offset(500f, 465f),
+                visiblePageIndices = visiblePages,
+                pageRootOffsets = pageRoots,
+                pageSizes = pageSizes,
+                fallbackPageIndex = 199
+            )
+        )
+        assertEquals(
+            199,
+            desktopPdfSpreadZoomAnchorPageIndex(
+                viewportRootOffset = Offset.Zero,
+                anchor = null,
+                visiblePageIndices = visiblePages,
+                pageRootOffsets = pageRoots,
+                pageSizes = pageSizes,
+                fallbackPageIndex = 199
+            )
+        )
+        val fittedSpread = desktopPdfSpreadLayoutPrediction(
+            viewportRootOffset = Offset.Zero,
+            viewportSize = IntSize(1920, 991),
+            visiblePageIndices = visiblePages,
+            pageCanvasSizes = mapOf(
+                199 to IntSize(667, 881),
+                200 to IntSize(667, 881)
+            ),
+            horizontalScroll = 0,
+            verticalScroll = 112,
+            paddingPx = 30f,
+            pageGapPx = 22.5f
+        ) ?: error("Expected fitted spread prediction")
+        assertEquals(0, fittedSpread.maxHorizontalScroll)
+        assertEquals(0, fittedSpread.maxVerticalScroll)
+        assertEquals(282f, fittedSpread.pageRootOffsets[199]?.x ?: -1f, 0.5f)
+        assertEquals(972f, fittedSpread.pageRootOffsets[200]?.x ?: -1f, 0.5f)
+        assertEquals(30f, fittedSpread.pageRootOffsets[200]?.y ?: -1f, 0.0001f)
+
+        val scrollableSpread = desktopPdfSpreadLayoutPrediction(
+            viewportRootOffset = Offset.Zero,
+            viewportSize = IntSize(1920, 991),
+            visiblePageIndices = visiblePages,
+            pageCanvasSizes = mapOf(
+                199 to IntSize(1371, 1810),
+                200 to IntSize(1371, 1810)
+            ),
+            horizontalScroll = 696,
+            verticalScroll = 575,
+            paddingPx = 30f,
+            pageGapPx = 22.5f
+        ) ?: error("Expected scrollable spread prediction")
+        assertEquals(905, scrollableSpread.maxHorizontalScroll)
+        assertEquals(879, scrollableSpread.maxVerticalScroll)
+        assertEquals(-666f, scrollableSpread.pageRootOffsets[199]?.x ?: 0f, 0.5f)
+        assertEquals(728f, scrollableSpread.pageRootOffsets[200]?.x ?: 0f, 0.5f)
+        assertEquals(-545f, scrollableSpread.pageRootOffsets[200]?.y ?: 0f, 0.0001f)
+    }
+
+    @Test
+    fun `desktop pdf zoom preview bridges committed anchored zoom`() {
+        val preview = DesktopPdfZoomPreview(
+            baseZoom = 1f,
+            zoom = 2f,
+            anchor = Offset(100f, 100f),
+            displayMode = PdfDisplayMode.PAGINATION,
+            pageIndex = 0,
+            viewportRootOffset = Offset.Zero,
+            pageRootOffset = Offset.Zero
+        )
+
+        assertTrue(desktopPdfZoomPreviewMatchesScale(preview, 1f))
+        assertTrue(desktopPdfZoomPreviewMatchesScale(preview, 2f))
+        assertFalse(desktopPdfZoomPreviewMatchesScale(preview, 1.5f))
+        assertEquals(
+            Offset(-100f, -100f),
+            desktopPdfZoomCommitPreviewTranslation(
+                viewportRootOffset = Offset.Zero,
+                oldPageRootOffset = Offset.Zero,
+                currentAnchorPageRootOffset = Offset.Zero,
+                anchor = Offset(100f, 100f),
+                oldZoom = 1f,
+                newZoom = 2f,
+                currentZoom = 2f
+            )
+        )
+        assertEquals(
+            Offset.Zero,
+            desktopPdfZoomCommitPreviewTranslation(
+                viewportRootOffset = Offset.Zero,
+                oldPageRootOffset = Offset.Zero,
+                currentAnchorPageRootOffset = Offset(-100f, -100f),
+                anchor = Offset(100f, 100f),
+                oldZoom = 1f,
+                newZoom = 2f,
+                currentZoom = 2f
+            )
+        )
+        assertEquals(
+            null,
+            desktopPdfZoomCommitPreviewTranslation(
+                viewportRootOffset = Offset.Zero,
+                oldPageRootOffset = Offset.Zero,
+                currentAnchorPageRootOffset = Offset.Zero,
+                anchor = Offset(100f, 100f),
+                oldZoom = 1f,
+                newZoom = 2f,
+                currentZoom = 1f
+            )
+        )
+        assertEquals(0, desktopPdfReachableScrollDelta(currentScroll = 0, maxScroll = 0, requestedDelta = 100))
+        assertEquals(0, desktopPdfReachableScrollDelta(currentScroll = 0, maxScroll = 200, requestedDelta = -40))
+        assertEquals(-40, desktopPdfReachableScrollDelta(currentScroll = 80, maxScroll = 200, requestedDelta = -40))
+        assertEquals(
+            Offset.Zero,
+            desktopPdfZoomCommitPreviewTranslation(
+                viewportRootOffset = Offset.Zero,
+                oldPageRootOffset = Offset.Zero,
+                currentAnchorPageRootOffset = Offset.Zero,
+                anchor = Offset(100f, 100f),
+                oldZoom = 1f,
+                newZoom = 2f,
+                currentZoom = 2f,
+                scrollBounds = DesktopPdfZoomScrollBounds(
+                    currentHorizontalScroll = 0,
+                    maxHorizontalScroll = 0,
+                    currentVerticalScroll = 0,
+                    maxVerticalScroll = 0
+                )
+            )
+        )
+        assertEquals(
+            Offset(-50f, -25f),
+            desktopPdfZoomCommitPreviewTranslation(
+                viewportRootOffset = Offset.Zero,
+                oldPageRootOffset = Offset.Zero,
+                currentAnchorPageRootOffset = Offset.Zero,
+                anchor = Offset(100f, 100f),
+                oldZoom = 1f,
+                newZoom = 2f,
+                currentZoom = 2f,
+                scrollBounds = DesktopPdfZoomScrollBounds(
+                    currentHorizontalScroll = 0,
+                    maxHorizontalScroll = 50,
+                    currentVerticalScroll = 0,
+                    maxVerticalScroll = 25
+                )
+            )
+        )
+        val pendingCommitBounds = desktopPdfZoomScrollBoundsWithCommitTargets(
+            preview = preview.copy(
+                commitTargetHorizontalScroll = 300,
+                commitTargetVerticalScroll = 300
+            ),
+            currentHorizontalScroll = 0,
+            maxHorizontalScroll = 0,
+            currentVerticalScroll = 0,
+            maxVerticalScroll = 0
+        )
+        assertEquals(300, pendingCommitBounds.maxHorizontalScroll)
+        assertEquals(300, pendingCommitBounds.maxVerticalScroll)
+        assertEquals(
+            Offset(-100f, -100f),
+            desktopPdfZoomCommitPreviewTranslation(
+                viewportRootOffset = Offset.Zero,
+                oldPageRootOffset = Offset.Zero,
+                currentAnchorPageRootOffset = Offset.Zero,
+                anchor = Offset(100f, 100f),
+                oldZoom = 1f,
+                newZoom = 2f,
+                currentZoom = 2f,
+                scrollBounds = pendingCommitBounds
+            )
+        )
+        val fittingPagePrediction = desktopPdfSinglePageLayoutPrediction(
+            viewportRootOffset = Offset.Zero,
+            viewportSize = IntSize(1920, 991),
+            pageCanvasSize = IntSize(1216, 1605),
+            horizontalScroll = 0,
+            verticalScroll = 0,
+            paddingPx = 30f
+        ) ?: error("Expected fitting page prediction")
+        assertEquals(Offset(352f, 30f), fittingPagePrediction.rootOffset)
+        assertEquals(0, fittingPagePrediction.maxHorizontalScroll)
+        assertEquals(674, fittingPagePrediction.maxVerticalScroll)
+
+        val oversizedPagePrediction = desktopPdfSinglePageLayoutPrediction(
+            viewportRootOffset = Offset.Zero,
+            viewportSize = IntSize(1920, 991),
+            pageCanvasSize = IntSize(2498, 3298),
+            horizontalScroll = 409,
+            verticalScroll = 1122,
+            paddingPx = 30f
+        ) ?: error("Expected oversized page prediction")
+        assertEquals(Offset(-379f, -1092f), oversizedPagePrediction.rootOffset)
+        assertEquals(638, oversizedPagePrediction.maxHorizontalScroll)
+        assertEquals(2367, oversizedPagePrediction.maxVerticalScroll)
+    }
+
     @Test
     fun `desktop pdf anchored zoom keeps cursor content stable`() {
         assertEquals(

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopReaderKeyCommandsTest.kt

@@ -0,0 +1,174 @@
+package com.aryan.reader.desktop
+
+import java.awt.Canvas
+import java.awt.event.KeyEvent
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+
+class DesktopReaderKeyCommandsTest {
+
+    @Test
+    fun `ctrl f opens epub reader search`() {
+        assertEquals(
+            DesktopReaderKeyNavigation.SEARCH,
+            awtKeyEvent(KeyEvent.VK_F, KeyEvent.CTRL_DOWN_MASK, 'F')
+                .desktopReaderKeyNavigationOrNull(fullscreen = false)
+        )
+    }
+
+    @Test
+    fun `epub right to left pagination swaps physical arrow navigation`() {
+        assertEquals(
+            DesktopReaderKeyNavigation.PREVIOUS,
+            awtKeyEvent(KeyEvent.VK_RIGHT, 0, KeyEvent.CHAR_UNDEFINED)
+                .desktopReaderKeyNavigationOrNull(fullscreen = false, rightToLeftPagination = true)
+        )
+        assertEquals(
+            DesktopReaderKeyNavigation.NEXT,
+            awtKeyEvent(KeyEvent.VK_LEFT, 0, KeyEvent.CHAR_UNDEFINED)
+                .desktopReaderKeyNavigationOrNull(fullscreen = false, rightToLeftPagination = true)
+        )
+        assertEquals(
+            DesktopReaderKeyNavigation.NEXT,
+            awtKeyEvent(KeyEvent.VK_PAGE_DOWN, 0, KeyEvent.CHAR_UNDEFINED)
+                .desktopReaderKeyNavigationOrNull(fullscreen = false, rightToLeftPagination = true)
+        )
+    }
+
+    @Test
+    fun `ctrl f opens pdf reader search while reading`() {
+        assertEquals(
+            DesktopPdfKeyCommand.SEARCH,
+            awtKeyEvent(KeyEvent.VK_F, KeyEvent.CTRL_DOWN_MASK, 'F')
+                .desktopPdfKeyCommandOrNull(fullscreen = false, editingText = false)
+        )
+    }
+
+    @Test
+    fun `ctrl f opens pdf reader search while text editing`() {
+        assertEquals(
+            DesktopPdfKeyCommand.SEARCH,
+            awtKeyEvent(KeyEvent.VK_F, KeyEvent.CTRL_DOWN_MASK, 'F')
+                .desktopPdfKeyCommandOrNull(fullscreen = false, editingText = true)
+        )
+    }
+
+    @Test
+    fun `pdf text editing keeps unmodified arrows for the editor`() {
+        assertNull(
+            awtKeyEvent(KeyEvent.VK_LEFT, 0, KeyEvent.CHAR_UNDEFINED)
+                .desktopPdfKeyCommandOrNull(fullscreen = false, editingText = true)
+        )
+    }
+
+    @Test
+    fun `pdf right to left pagination swaps physical arrow navigation`() {
+        assertEquals(
+            DesktopPdfKeyCommand.PREVIOUS_PAGE,
+            awtKeyEvent(KeyEvent.VK_RIGHT, 0, KeyEvent.CHAR_UNDEFINED)
+                .desktopPdfKeyCommandOrNull(
+                    fullscreen = false,
+                    editingText = false,
+                    rightToLeftPagination = true
+                )
+        )
+        assertEquals(
+            DesktopPdfKeyCommand.NEXT_PAGE,
+            awtKeyEvent(KeyEvent.VK_LEFT, 0, KeyEvent.CHAR_UNDEFINED)
+                .desktopPdfKeyCommandOrNull(
+                    fullscreen = false,
+                    editingText = false,
+                    rightToLeftPagination = true
+                )
+        )
+        assertEquals(
+            DesktopPdfKeyCommand.NEXT_PAGE,
+            awtKeyEvent(KeyEvent.VK_PAGE_DOWN, 0, KeyEvent.CHAR_UNDEFINED)
+                .desktopPdfKeyCommandOrNull(
+                    fullscreen = false,
+                    editingText = false,
+                    rightToLeftPagination = true
+                )
+        )
+    }
+
+    @Test
+    fun `reader side panels can opt into global key dispatch without enabling popups`() {
+        assertEquals(
+            DesktopReaderModalWindowKind.PANEL,
+            desktopReaderModalWindowKind(
+                windowName = "${DesktopReaderModalWindowNamePrefix}PanelLeft",
+                windowTitle = "Reader Navigation"
+            )
+        )
+        assertTrue(
+            desktopReaderKeyDispatchAllowedForActiveWindowKind(
+                activeReaderModalKind = DesktopReaderModalWindowKind.PANEL,
+                allowChromeModalWindows = false,
+                allowPanelModalWindows = true,
+                dispatchWhenOwnerWindowActive = false
+            )
+        )
+        assertFalse(
+            desktopReaderKeyDispatchAllowedForActiveWindowKind(
+                activeReaderModalKind = DesktopReaderModalWindowKind.POPUP,
+                allowChromeModalWindows = true,
+                allowPanelModalWindows = true,
+                dispatchWhenOwnerWindowActive = true
+            )
+        )
+    }
+
+    @Test
+    fun `reader chrome and owner window dispatch remain separately gated`() {
+        assertEquals(
+            DesktopReaderModalWindowKind.CHROME,
+            desktopReaderModalWindowKind(
+                windowName = "${DesktopReaderModalWindowNamePrefix}ChromeTop",
+                windowTitle = "Reader Chrome Top"
+            )
+        )
+        assertEquals(
+            DesktopReaderModalWindowKind.POPUP,
+            desktopReaderModalWindowKind(
+                windowName = "${DesktopReaderModalWindowNamePrefix}Popup",
+                windowTitle = "Reader Popup"
+            )
+        )
+        assertNull(desktopReaderModalWindowKind(windowName = "", windowTitle = "Episteme"))
+        assertFalse(
+            desktopReaderKeyDispatchAllowedForActiveWindowKind(
+                activeReaderModalKind = null,
+                allowChromeModalWindows = false,
+                allowPanelModalWindows = true,
+                dispatchWhenOwnerWindowActive = false
+            )
+        )
+        assertTrue(
+            desktopReaderKeyDispatchAllowedForActiveWindowKind(
+                activeReaderModalKind = DesktopReaderModalWindowKind.CHROME,
+                allowChromeModalWindows = true,
+                allowPanelModalWindows = false,
+                dispatchWhenOwnerWindowActive = false
+            )
+        )
+    }
+
+    private fun awtKeyEvent(
+        keyCode: Int,
+        modifiers: Int,
+        keyChar: Char
+    ): KeyEvent {
+        return KeyEvent(
+            Canvas(),
+            KeyEvent.KEY_PRESSED,
+            0L,
+            modifiers,
+            keyCode,
+            keyChar
+        )
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopReaderTypographyTest.kt

@@ -0,0 +1,69 @@
+package com.aryan.reader.desktop
+
+import androidx.compose.ui.unit.sp
+import com.aryan.reader.paginatedreader.CssStyle
+import com.aryan.reader.paginatedreader.SemanticParagraph
+import com.aryan.reader.shared.reader.ReaderPage
+import kotlin.test.Test
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class DesktopReaderTypographyTest {
+
+    @Test
+    fun `same page layout includes semantic styling`() {
+        val plain = pageWith(
+            SemanticParagraph(
+                text = "Styled text",
+                spans = emptyList(),
+                style = CssStyle(),
+                elementId = null,
+                cfi = null,
+                startCharOffsetInSource = 0,
+                blockIndex = 0
+            )
+        )
+        val styled = pageWith(
+            SemanticParagraph(
+                text = "Styled text",
+                spans = emptyList(),
+                style = CssStyle(fontSize = 24.sp),
+                elementId = null,
+                cfi = null,
+                startCharOffsetInSource = 0,
+                blockIndex = 0
+            )
+        )
+
+        assertFalse(listOf(plain).samePageLayoutAs(listOf(styled)))
+    }
+
+    @Test
+    fun `same page layout still matches identical semantic pages`() {
+        val page = pageWith(
+            SemanticParagraph(
+                text = "Styled text",
+                spans = emptyList(),
+                style = CssStyle(fontSize = 24.sp),
+                elementId = null,
+                cfi = null,
+                startCharOffsetInSource = 0,
+                blockIndex = 0
+            )
+        )
+
+        assertTrue(listOf(page).samePageLayoutAs(listOf(page.copy())))
+    }
+
+    private fun pageWith(block: SemanticParagraph): ReaderPage {
+        return ReaderPage(
+            pageIndex = 0,
+            chapterIndex = 0,
+            chapterTitle = "One",
+            text = block.text,
+            startOffset = 0,
+            endOffset = block.text.length,
+            semanticBlocks = listOf(block)
+        )
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopReaderWindowStateTest.kt

@@ -1,14 +1,23 @@
 package com.aryan.reader.desktop
 
+import androidx.compose.ui.unit.dp
+import androidx.compose.ui.window.WindowPlacement
 import com.aryan.reader.shared.FileType
+import com.aryan.reader.shared.reader.ReaderReadingMode
 import com.aryan.reader.shared.ui.SharedAppTab
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
+import kotlin.test.assertNull
 import kotlin.test.assertTrue
 
 class DesktopReaderWindowStateTest {
 
+    @Test
+    fun `desktop starts on library instead of home`() {
+        assertEquals(SharedAppTab.LIBRARY, DesktopInitialAppTab)
+    }
+
     @Test
     fun `opening a new reader creates a window`() {
         val opening = readerOpening("book-1", requestId = 1)
@@ -59,6 +68,67 @@ class DesktopReaderWindowStateTest {
         assertEquals(2L, decision.windows.single().focusRequestId)
     }
 
+    @Test
+    fun `reader window uses persisted size instead of hardcoded fallback`() {
+        val snapshot = DesktopWindowStateSnapshot(
+            placement = DesktopSavedWindowPlacement.FLOATING,
+            widthDp = 1340f,
+            heightDp = 840f
+        )
+
+        val size = snapshot.toWindowSize(DesktopReaderWindowDefaultSize)
+
+        assertEquals(1340.dp, size.width)
+        assertEquals(840.dp, size.height)
+    }
+
+    @Test
+    fun `reader window defaults preserve previous detached reader size`() {
+        assertEquals(1120.dp, DesktopReaderWindowDefaultSize.width)
+        assertEquals(760.dp, DesktopReaderWindowDefaultSize.height)
+    }
+
+    @Test
+    fun `reader window persistence ignores fullscreen snapshots`() {
+        val snapshot = DesktopWindowStateSnapshot(
+            placement = DesktopSavedWindowPlacement.FULLSCREEN,
+            widthDp = 1920f,
+            heightDp = 1080f
+        )
+
+        assertEquals(WindowPlacement.Floating, snapshot.toReaderWindowPlacement())
+        assertNull(snapshot.toPersistableReaderWindowSnapshot())
+    }
+
+    @Test
+    fun `native webview text reader resets surface when switching from vertical to paginated`() {
+        assertTrue(
+            shouldResetDesktopTextReaderWindowSurface(
+                previousMode = ReaderReadingMode.VERTICAL,
+                currentMode = ReaderReadingMode.PAGINATED,
+                usesNativeWebView = true
+            )
+        )
+    }
+
+    @Test
+    fun `text reader surface reset is limited to native webview vertical to paginated switches`() {
+        assertFalse(
+            shouldResetDesktopTextReaderWindowSurface(
+                previousMode = ReaderReadingMode.PAGINATED,
+                currentMode = ReaderReadingMode.VERTICAL,
+                usesNativeWebView = true
+            )
+        )
+        assertFalse(
+            shouldResetDesktopTextReaderWindowSurface(
+                previousMode = ReaderReadingMode.VERTICAL,
+                currentMode = ReaderReadingMode.PAGINATED,
+                usesNativeWebView = false
+            )
+        )
+    }
+
     private fun readerOpening(bookId: String, requestId: Long): DesktopReaderOpening {
         return DesktopReaderOpening(
             requestId = requestId,

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopStartupTest.kt

@@ -1,10 +1,13 @@
 package com.aryan.reader.desktop
 
-import com.aryan.reader.shared.ReaderFeatureSurface
+import com.aryan.reader.shared.SharedReaderScreenState
 import kotlin.test.Test
 import kotlin.test.assertEquals
 import kotlin.test.assertFalse
+import kotlin.test.assertNull
 import kotlin.test.assertTrue
+import java.io.File
+import java.nio.file.Files
 
 class DesktopStartupTest {
     @Test
@@ -25,34 +28,174 @@ class DesktopStartupTest {
     }
 
     @Test
-    fun `embedded webview starts only for epub backed reader surfaces`() {
-        assertTrue(shouldRequestDesktopWebViewRuntime(ReaderFeatureSurface.EPUB_READER))
-        assertTrue(shouldRequestDesktopWebViewRuntime(ReaderFeatureSurface.TEXT_READER))
-        assertFalse(shouldRequestDesktopWebViewRuntime(ReaderFeatureSurface.PDF_VIEWER))
-        assertFalse(shouldRequestDesktopWebViewRuntime(null))
+    fun `desktop epub webview uses native browser backends without bundled runtime`() {
+        val linux = DesktopPlatform(DesktopOperatingSystem.LINUX, DesktopArchitecture.X64)
+        val windows = DesktopPlatform(DesktopOperatingSystem.WINDOWS, DesktopArchitecture.X64)
+        val macos = DesktopPlatform(DesktopOperatingSystem.MACOS, DesktopArchitecture.ARM64)
+        val other = DesktopPlatform(DesktopOperatingSystem.OTHER, DesktopArchitecture.X64)
+
+        assertEquals(DesktopEpubWebViewBackend.WEBKIT, desktopEpubWebViewBackend(linux))
+        assertEquals(DesktopEpubWebViewBackend.WINDOWS_WEBVIEW2, desktopEpubWebViewBackend(windows))
+        assertEquals(DesktopEpubWebViewBackend.WEBKIT, desktopEpubWebViewBackend(macos))
+        assertEquals(DesktopEpubWebViewBackend.UNSUPPORTED, desktopEpubWebViewBackend(other))
+
+        assertTrue(desktopEpubWebViewUsesNativeSwtBrowser(linux))
+        assertTrue(desktopEpubWebViewUsesNativeSwtBrowser(windows))
+        assertTrue(desktopEpubWebViewUsesNativeSwtBrowser(macos))
+        assertFalse(desktopEpubWebViewUsesNativeSwtBrowser(other))
     }
 
     @Test
-    fun `embedded webview startup skips terminal runtime states`() {
-        assertFalse(shouldStartDesktopWebViewRuntime(requested = false, state = DesktopWebViewRuntimeState()))
-        assertTrue(shouldStartDesktopWebViewRuntime(requested = true, state = DesktopWebViewRuntimeState()))
-        assertFalse(
-            shouldStartDesktopWebViewRuntime(
-                requested = true,
-                state = DesktopWebViewRuntimeState(initialized = true)
-            )
+    fun `native webviews can render without bundled runtime state`() {
+        val windows = DesktopPlatform(DesktopOperatingSystem.WINDOWS, DesktopArchitecture.X64)
+        val linux = DesktopPlatform(DesktopOperatingSystem.LINUX, DesktopArchitecture.X64)
+        val macos = DesktopPlatform(DesktopOperatingSystem.MACOS, DesktopArchitecture.ARM64)
+        val other = DesktopPlatform(DesktopOperatingSystem.OTHER, DesktopArchitecture.X64)
+
+        assertTrue(desktopEpubWebViewCanRender(DesktopWebViewRuntimeState(), windows))
+        assertTrue(desktopEpubWebViewCanRender(DesktopWebViewRuntimeState(), linux))
+        assertTrue(desktopEpubWebViewCanRender(DesktopWebViewRuntimeState(), macos))
+        assertTrue(desktopEpubWebViewCanRender(DesktopWebViewRuntimeState(initialized = true), linux))
+        assertFalse(desktopEpubWebViewCanRender(DesktopWebViewRuntimeState(initialized = true), other))
+    }
+
+    @Test
+    fun `native webview unavailable messages point to the platform runtime`() {
+        val windowsMessage = desktopNativeWebViewUnavailableMessage(
+            backend = DesktopEpubWebViewBackend.WINDOWS_WEBVIEW2,
+            detail = "missing runtime"
         )
-        assertFalse(
-            shouldStartDesktopWebViewRuntime(
-                requested = true,
-                state = DesktopWebViewRuntimeState(restartRequired = true)
-            )
+        val linuxMessage = desktopNativeWebViewUnavailableMessage(
+            backend = DesktopEpubWebViewBackend.WEBKIT,
+            detail = "missing library"
         )
-        assertFalse(
-            shouldStartDesktopWebViewRuntime(
-                requested = true,
-                state = DesktopWebViewRuntimeState(errorMessage = "missing bundle")
+
+        assertTrue(windowsMessage.contains("WebView2 Runtime"))
+        assertTrue(windowsMessage.contains("missing runtime"))
+        assertTrue(linuxMessage.contains("WebKitGTK"))
+        assertTrue(linuxMessage.contains("Linux distribution packages"))
+        assertTrue(linuxMessage.contains("missing library"))
+    }
+
+    @Test
+    fun `compose interop blending stays off by default for native swt webviews`() {
+        val windows = DesktopPlatform(DesktopOperatingSystem.WINDOWS, DesktopArchitecture.X64)
+        val linux = DesktopPlatform(DesktopOperatingSystem.LINUX, DesktopArchitecture.X64)
+        val other = DesktopPlatform(DesktopOperatingSystem.OTHER, DesktopArchitecture.X64)
+
+        assertNull(composeInteropBlendingDefault(windows))
+        assertNull(composeInteropBlendingDefault(linux))
+        assertEquals(ComposeInteropBlendingEnabled, composeInteropBlendingDefault(other))
+    }
+
+    @Test
+    fun `silent startup folder sync does not surface missing folder banner`() {
+        val completed = desktopFolderSyncCompletedState(
+            state = SharedReaderScreenState(),
+            message = "Folder sync failed for 1 folder.",
+            failedFolderCount = 1,
+            showBanner = false
+        )
+
+        assertNull(completed.bannerMessage)
+    }
+
+    @Test
+    fun `manual folder sync still surfaces missing folder banner`() {
+        val completed = desktopFolderSyncCompletedState(
+            state = SharedReaderScreenState(),
+            message = "Folder sync failed for 1 folder.",
+            failedFolderCount = 1,
+            showBanner = true
+        )
+
+        assertEquals("Folder sync failed for 1 folder.", completed.bannerMessage?.message)
+        assertTrue(completed.bannerMessage?.isError == true)
+    }
+
+    @Test
+    fun `desktop account profile store restores cached profile for matching user`() {
+        val directory = Files.createTempDirectory("episteme-account-profile-test").toFile()
+        try {
+            val store = DesktopAccountProfileStore(File(directory, "account_profile.properties"))
+            store.save("user-1", DesktopAccountProfile(isProUser = true, credits = 42, fetchedAtEpochMillis = 123L))
+
+            assertEquals(
+                DesktopAccountProfile(isProUser = true, credits = 42, fetchedAtEpochMillis = 123L),
+                store.load("user-1")
             )
+            assertNull(store.load("user-2"))
+        } finally {
+            directory.deleteRecursively()
+        }
+    }
+
+    @Test
+    fun `desktop account profile freshness uses fetched timestamp`() {
+        val now = 10_000L
+        val ttl = 1_000L
+
+        assertTrue(DesktopAccountProfile(fetchedAtEpochMillis = now - ttl).isFresh(now, ttl))
+        assertTrue(DesktopAccountProfile(fetchedAtEpochMillis = now - 1L).isFresh(now, ttl))
+        assertFalse(DesktopAccountProfile(fetchedAtEpochMillis = now - ttl - 1L).isFresh(now, ttl))
+        assertFalse(DesktopAccountProfile(fetchedAtEpochMillis = now + 1L).isFresh(now, ttl))
+        assertFalse(DesktopAccountProfile(fetchedAtEpochMillis = 0L).isFresh(now, ttl))
+    }
+
+    @Test
+    fun `desktop account profile repository ignores stale startup cache`() {
+        val directory = Files.createTempDirectory("episteme-account-profile-policy-test").toFile()
+        try {
+            val store = DesktopAccountProfileStore(File(directory, "account_profile.properties"))
+            val repository = DesktopAccountProfileRepository(testDesktopCloudConfig(), store)
+            val now = DesktopAccountProfileCacheTtlMillis + 10_000L
+            val freshProfile = DesktopAccountProfile(
+                isProUser = true,
+                credits = 42,
+                fetchedAtEpochMillis = now - DesktopAccountProfileCacheTtlMillis + 1L
+            )
+
+            repository.saveFetchedProfile("user-1", freshProfile)
+            assertEquals(freshProfile, repository.cachedProfile("user-1", now))
+
+            repository.saveFetchedProfile(
+                "user-1",
+                freshProfile.copy(fetchedAtEpochMillis = now - DesktopAccountProfileCacheTtlMillis - 1L)
+            )
+            assertNull(repository.cachedProfile("user-1", now))
+        } finally {
+            directory.deleteRecursively()
+        }
+    }
+
+    @Test
+    fun `desktop account profile repository clear removes sign out cache`() {
+        val directory = Files.createTempDirectory("episteme-account-profile-clear-test").toFile()
+        try {
+            val store = DesktopAccountProfileStore(File(directory, "account_profile.properties"))
+            val repository = DesktopAccountProfileRepository(testDesktopCloudConfig(), store)
+
+            repository.saveFetchedProfile(
+                "user-1",
+                DesktopAccountProfile(isProUser = true, credits = 42, fetchedAtEpochMillis = 10_000L)
+            )
+            repository.clearCachedProfiles()
+
+            assertNull(repository.cachedProfile("user-1", 10_001L))
+            assertNull(store.load("user-1"))
+        } finally {
+            directory.deleteRecursively()
+        }
+    }
+
+    private fun testDesktopCloudConfig(): DesktopCloudConfig {
+        return DesktopCloudConfig(
+            aiWorkerUrl = "",
+            ttsWorkerUrl = "",
+            firebaseWebApiKey = "",
+            firebaseProjectId = "reader-test",
+            googleOAuthClientId = "",
+            googleOAuthClientSecret = ""
         )
     }
 }

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopStringResourcesTest.kt

@@ -72,6 +72,24 @@ class DesktopStringResourcesTest {
         assertEquals("Don't skip %1${'$'}d file", parsed["quoted_count"]?.get("one"))
     }
 
+    @Test
+    fun loadsAndroidToolbarTooltipDescriptionsForDesktop() {
+        val resources = DesktopAndroidStringResources.load(
+            locale = Locale.ENGLISH,
+            classLoader = Thread.currentThread().contextClassLoader
+                ?: DesktopStringResourcesTest::class.java.classLoader
+        )
+
+        assertEquals(
+            "Exit search and go back to the reader",
+            resources.stringOrNull("tooltip_close_search_desc")
+        )
+        assertEquals(
+            "Jump to the next search match in the document",
+            resources.stringOrNull("tooltip_next_result_desc")
+        )
+    }
+
     @Test
     fun choosesDesktopPluralQuantityForSupportedLanguages() {
         val slavicQuantities = setOf("one", "few", "many", "other")

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopTtsLogTest.kt

@@ -0,0 +1,18 @@
+package com.aryan.reader.desktop
+
+import kotlin.test.Test
+import kotlin.test.assertFalse
+import kotlin.test.assertTrue
+
+class DesktopTtsLogTest {
+    @Test
+    fun `desktop tts preview redacts key and token query values`() {
+        val preview = "wss://example.test/live?key=gemini_secret&token=firebase_secret"
+            .desktopTtsPreview(300)
+
+        assertFalse(preview.contains("gemini_secret"))
+        assertFalse(preview.contains("firebase_secret"))
+        assertTrue(preview.contains("key=<redacted>"))
+        assertTrue(preview.contains("token=<redacted>"))
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopWebView2LayoutTest.kt

@@ -0,0 +1,44 @@
+package com.aryan.reader.desktop
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertFalse
+import kotlin.test.assertNull
+import kotlin.test.assertTrue
+
+class DesktopWebView2LayoutTest {
+    @Test
+    fun `webview2 host bounds match the awt canvas logical size`() {
+        val bounds = desktopWebView2TargetBoundsForCanvas(width = 1440, height = 900)
+
+        assertEquals(DesktopWebView2TargetBounds(x = 0, y = 0, width = 1440, height = 900), bounds)
+    }
+
+    @Test
+    fun `webview2 host bounds are unavailable before the canvas has size`() {
+        assertNull(desktopWebView2TargetBoundsForCanvas(width = 0, height = 900))
+        assertNull(desktopWebView2TargetBoundsForCanvas(width = 1440, height = 0))
+    }
+
+    @Test
+    fun `webview2 awt canvas is not retired while host window is closing`() {
+        assertFalse(
+            desktopWebView2ShouldRetireAwtCanvas(
+                hostWindowClosing = true,
+                hostWindowDisplayable = true
+            )
+        )
+        assertFalse(
+            desktopWebView2ShouldRetireAwtCanvas(
+                hostWindowClosing = false,
+                hostWindowDisplayable = false
+            )
+        )
+        assertTrue(
+            desktopWebView2ShouldRetireAwtCanvas(
+                hostWindowClosing = false,
+                hostWindowDisplayable = true
+            )
+        )
+    }
+}

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/DesktopWindowStateStoreTest.kt

@@ -34,4 +34,10 @@ class DesktopWindowStateStoreTest {
         assertEquals(EpistemeDesktopWindowMinimumWidthPx.toFloat(), snapshot.widthDp)
         assertEquals(EpistemeDesktopWindowMinimumHeightPx.toFloat(), snapshot.heightDp)
     }
+
+    @Test
+    fun `reader window state uses a separate config file`() {
+        assertEquals("window_state.json", DesktopWindowStateStore.defaultWindowStateFile().name)
+        assertEquals("reader_window_state.json", DesktopWindowStateStore.defaultReaderWindowStateFile().name)
+    }
 }

desktopApp/src/desktopTest/kotlin/com/aryan/reader/desktop/LinuxSecretToolCodecTest.kt

@@ -0,0 +1,55 @@
+package com.aryan.reader.desktop
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+import kotlin.test.assertTrue
+
+class LinuxSecretToolCodecTest {
+    @Test
+    fun `secret tool codec stores looks up and clears secrets by key`() {
+        val runner = FakeSecretCommandRunner()
+        val codec = LinuxSecretToolCodec(runner)
+
+        assertTrue(codec.isAvailable)
+        val reference = codec.protect("firebaseRefreshTokenProtected", "linux_refresh")
+
+        assertEquals("linux_refresh", codec.unprotect("firebaseRefreshTokenProtected", reference))
+        codec.delete("firebaseRefreshTokenProtected")
+        assertTrue(runner.storedSecrets.isEmpty())
+    }
+
+    private class FakeSecretCommandRunner : DesktopSecretCommandRunner {
+        val storedSecrets = linkedMapOf<String, String>()
+
+        override fun isExecutableAvailable(command: String): Boolean {
+            return command == "secret-tool"
+        }
+
+        override fun run(
+            command: List<String>,
+            input: String?,
+            timeoutMillis: Long
+        ): DesktopSecretCommandResult {
+            return when (command.getOrNull(1)) {
+                "--help" -> DesktopSecretCommandResult(0, "usage", "")
+                "store" -> {
+                    storedSecrets[command.last()] = input.orEmpty()
+                    DesktopSecretCommandResult(0, "", "")
+                }
+                "lookup" -> {
+                    val secret = storedSecrets[command.last()]
+                    if (secret == null) {
+                        DesktopSecretCommandResult(1, "", "not found")
+                    } else {
+                        DesktopSecretCommandResult(0, "$secret\n", "")
+                    }
+                }
+                "clear" -> {
+                    storedSecrets.remove(command.last())
+                    DesktopSecretCommandResult(0, "", "")
+                }
+                else -> DesktopSecretCommandResult(1, "", "unexpected command")
+            }
+        }
+    }
+}