Pdf reader improvments (#113)

* Improve PDF rendering quality and performance.

- Set `FilterQuality.High` when drawing base bitmaps and high-res tiles in `PdfPageComposable`.
- Implement `inSampleSize` calculation in `UniversalDocument` to optimize memory usage during region decoding.
- Enhance bitmap drawing quality by adding `ANTI_ALIAS_FLAG` and `DITHER_FLAG` to the paint configuration.

* Implement custom reader themes for PDF viewer.

This change integrates the `ReaderThemePanel` and theme management logic into the PDF viewer, allowing users to apply preset or custom themes. Previously, the PDF viewer only supported a simple dark mode toggle.

Specific changes:
- Moved `ReaderTheme`, `ReaderTexture`, and theme-related utility functions from `EpubReaderScreen.kt` to `Common.kt` to allow sharing between EPUB and PDF readers.
- Updated `PdfPageComposable` to use `activeTheme` instead of `isDarkMode`, implementing a `ColorMatrix` to apply custom background and text colors to PDF pages.
- Replaced the dark mode toggle in `PdfViewerScreen` with a theme selection button that opens `ReaderThemePanel`.
- Introduced `PdfBuiltInThemes` to provide PDF-specific theme presets.

* Reset page transformation on constraint changes and refine tile rendering logic.

- Reset scale to 1.0 and offset to zero in `PdfPageComposable` when constraints change.
- Update `UniversalDocument` to use floating-point precision for source rectangle calculations and `RectF` for destination mapping to improve rendering accuracy.

* Improve eraser hit detection and visual thickness settings in PDF reader.

app/src/main/java/com/aryan/reader/Common.kt

@@ -1,48 +1,27 @@
-/*
+// Common.kt
- * Episteme Reader - A native Android document reader.
- * Copyright (C) 2026 Episteme
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Affero General Public License as
- * published by the Free Software Foundation, either version 3 of the
- * License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU Affero General Public License for more details.
- *
- * You should have received a copy of the GNU Affero General Public License
- * along with this program.  If not, see <https://www.gnu.org/licenses/>.
- *
- * mail: epistemereader@gmail.com
- */
 @file:kotlin.OptIn(ExperimentalMaterial3Api::class)
 
 package com.aryan.reader
 
 import android.content.Context
-import androidx.annotation.OptIn
+import android.speech.tts.TextToSpeech
+import android.speech.tts.Voice
+import androidx.compose.animation.AnimatedContent
+import androidx.compose.animation.AnimatedVisibility
+import androidx.compose.foundation.BorderStroke
+import androidx.compose.foundation.Canvas
 import androidx.compose.foundation.background
 import androidx.compose.foundation.border
-import androidx.compose.material3.TooltipBox
-import androidx.compose.material3.PlainTooltip
-import androidx.compose.material3.RichTooltip
-import androidx.compose.material3.rememberTooltipState
-import androidx.compose.material3.TooltipDefaults
 import androidx.compose.foundation.clickable
+import androidx.compose.foundation.gestures.awaitEachGesture
+import androidx.compose.foundation.gestures.awaitFirstDown
+import androidx.compose.foundation.gestures.drag
 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.WindowInsets
-import android.speech.tts.TextToSpeech
-import android.speech.tts.Voice
-import androidx.compose.foundation.Canvas
-import androidx.compose.foundation.gestures.awaitEachGesture
-import androidx.compose.foundation.gestures.awaitFirstDown
-import androidx.compose.foundation.gestures.drag
 import androidx.compose.foundation.layout.WindowInsetsSides
 import androidx.compose.foundation.layout.fillMaxHeight
 import androidx.compose.foundation.layout.fillMaxSize
@@ -59,6 +38,7 @@ import androidx.compose.foundation.lazy.LazyColumn
 import androidx.compose.foundation.lazy.items
 import androidx.compose.foundation.lazy.rememberLazyListState
 import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.foundation.text.BasicTextField
 import androidx.compose.foundation.text.KeyboardActions
@@ -66,16 +46,20 @@ import androidx.compose.foundation.text.KeyboardOptions
 import androidx.compose.foundation.verticalScroll
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.automirrored.filled.ArrowBack
+import androidx.compose.material.icons.filled.Add
 import androidx.compose.material.icons.filled.ArrowDropDown
 import androidx.compose.material.icons.filled.ArrowDropUp
 import androidx.compose.material.icons.filled.Check
 import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.Cloud
 import androidx.compose.material.icons.filled.ContentCopy
+import androidx.compose.material.icons.filled.Delete
+import androidx.compose.material.icons.filled.Edit
 import androidx.compose.material.icons.filled.GraphicEq
 import androidx.compose.material.icons.filled.PlayArrow
 import androidx.compose.material.icons.filled.Smartphone
 import androidx.compose.material.icons.filled.Stop
+import androidx.compose.material3.Button
 import androidx.compose.material3.Card
 import androidx.compose.material3.CardDefaults
 import androidx.compose.material3.CircularProgressIndicator
@@ -89,11 +73,18 @@ import androidx.compose.material3.ListItem
 import androidx.compose.material3.ListItemDefaults
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.ModalBottomSheet
+import androidx.compose.material3.PlainTooltip
+import androidx.compose.material3.RichTooltip
+import androidx.compose.material3.Slider
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
 import androidx.compose.material3.TextField
 import androidx.compose.material3.TextFieldDefaults
+import androidx.compose.material3.TooltipBox
+import androidx.compose.material3.TooltipDefaults
 import androidx.compose.material3.rememberModalBottomSheetState
+import androidx.compose.material3.rememberTooltipState
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.LaunchedEffect
@@ -101,6 +92,7 @@ import androidx.compose.runtime.Stable
 import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
+import androidx.compose.runtime.mutableFloatStateOf
 import androidx.compose.runtime.mutableIntStateOf
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
@@ -109,20 +101,29 @@ 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.draw.drawBehind
 import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.focus.focusRequester
 import androidx.compose.ui.geometry.Offset
+import androidx.compose.ui.graphics.BlendMode
 import androidx.compose.ui.graphics.Brush
 import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.graphics.ImageBitmap
+import androidx.compose.ui.graphics.ImageShader
+import androidx.compose.ui.graphics.ShaderBrush
 import androidx.compose.ui.graphics.SolidColor
+import androidx.compose.ui.graphics.TileMode
 import androidx.compose.ui.graphics.drawscope.Stroke
+import androidx.compose.ui.graphics.luminance
 import androidx.compose.ui.graphics.toArgb
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.platform.LocalClipboardManager
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalFocusManager
+import androidx.compose.ui.platform.LocalResources
 import androidx.compose.ui.platform.LocalSoftwareKeyboardController
 import androidx.compose.ui.platform.testTag
+import androidx.compose.ui.res.imageResource
 import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.AnnotatedString
@@ -141,7 +142,11 @@ import androidx.compose.ui.unit.dp
 import androidx.compose.ui.unit.sp
 import androidx.compose.ui.window.Popup
 import androidx.compose.ui.window.PopupProperties
+import androidx.core.content.edit
+import androidx.core.graphics.toColorInt
 import androidx.media3.common.util.UnstableApi
+import com.aryan.reader.epubreader.PREF_CUSTOM_THEMES
+import com.aryan.reader.epubreader.PREF_READER_THEME
 import com.aryan.reader.paginatedreader.TtsChunk
 import com.aryan.reader.tts.GOOGLE_TTS_SPEAKERS
 import com.aryan.reader.tts.SpeakerSamplePlayer
@@ -166,13 +171,14 @@ import org.commonmark.node.SoftLineBreak
 import org.commonmark.node.StrongEmphasis
 import org.commonmark.node.Text
 import org.commonmark.parser.Parser
+import org.json.JSONArray
 import org.json.JSONObject
 import timber.log.Timber
 import java.io.File
 import java.net.HttpURLConnection
 import java.net.URL
-import androidx.core.content.edit
+import kotlin.math.max
-import androidx.core.graphics.toColorInt
+import kotlin.math.min
 import kotlin.math.roundToInt
 
 const val aiServerBasePath = BuildConfig.AI_WORKER_URL
@@ -270,6 +276,7 @@ fun rememberSearchState(
 
 private val activeTooltipState = mutableStateOf<androidx.compose.material3.TooltipState?>(null)
 
+@OptIn(ExperimentalMaterial3Api::class)
 @Composable
 fun TooltipIconButton(
     text: String,
@@ -488,7 +495,7 @@ fun SearchNavigationControls(
     }
 }
 
-@OptIn(UnstableApi::class)
+@androidx.annotation.OptIn(UnstableApi::class)
 @Composable
 fun SummarizationPopup(
     title: String,
@@ -657,7 +664,7 @@ fun SummarizationPopup(
     }
 }
 
-@OptIn(UnstableApi::class)
+@androidx.annotation.OptIn(UnstableApi::class)
 @Composable
 fun AiDefinitionPopup(
     word: String?,
@@ -1151,7 +1158,7 @@ suspend fun fetchRecap(
     }
 }
 
-@OptIn(UnstableApi::class)
+@androidx.annotation.OptIn(UnstableApi::class)
 @Composable
 fun TtsSettingsSheet(
     isVisible: Boolean,
@@ -1662,12 +1669,12 @@ fun DeviceVoiceSettingsSheet(
 
                                         ListItem(
                                             headlineContent = {
-                                            Text(
+                                                Text(
-                                                text = friendlyName,
+                                                    text = friendlyName,
-                                                fontWeight = if (isSelected) FontWeight.Bold else FontWeight.Normal,
+                                                    fontWeight = if (isSelected) FontWeight.Bold else FontWeight.Normal,
-                                                color = MaterialTheme.colorScheme.onSurface
+                                                    color = MaterialTheme.colorScheme.onSurface
-                                            )
+                                                )
-                                        },
+                                            },
                                             supportingContent = if (voice.locale.variant.isNotEmpty()) {
                                                 { Text("Variant: ${voice.locale.variant}") }
                                             } else null,
@@ -2014,4 +2021,599 @@ fun ColorComparePill(
             size = androidx.compose.ui.geometry.Size(size.width / 2, size.height)
         )
     }
+}
+
+enum class ReaderTexture(val id: String, val resId: Int, val displayName: String) {
+    PAPER("paper", R.drawable.texture_paper, "Paper"),
+    CANVAS("canvas", R.drawable.texture_canvas, "Canvas"),
+    EINK("eink", R.drawable.texture_eink, "E-Ink"),
+    SLATE("slate", R.drawable.texture_slate, "Slate")
+}
+
+data class ReaderTheme(
+    val id: String,
+    val name: String,
+    val backgroundColor: Color,
+    val textColor: Color,
+    val isDark: Boolean,
+    val textureId: String? = null,
+    val isCustom: Boolean = false
+)
+
+val BuiltInThemes = listOf(
+    ReaderTheme("system", "System", Color.Unspecified, Color.Unspecified, false),
+    ReaderTheme("light", "Light", Color(0xFFFFFFFF), Color(0xFF000000), false),
+    ReaderTheme("dark", "Dark", Color(0xFF121212), Color(0xFFE0E0E0), true),
+    ReaderTheme("sepia", "Sepia", Color(0xFFFBF0D9), Color(0xFF5F4B32), false),
+    ReaderTheme("slate", "Slate", Color(0xFF2E3440), Color(0xFFECEFF4), true),
+    ReaderTheme("oled", "OLED", Color(0xFF000000), Color(0xFFB0B0B0), true)
+)
+
+fun saveReaderThemeId(context: Context, themeId: String) {
+    val prefs = context.getSharedPreferences("reader_prefs", Context.MODE_PRIVATE)
+    prefs.edit { putString(PREF_READER_THEME, themeId) }
+}
+
+fun loadReaderThemeId(context: Context): String {
+    val prefs = context.getSharedPreferences("reader_prefs", Context.MODE_PRIVATE)
+    return prefs.getString(PREF_READER_THEME, "system") ?: "system"
+}
+
+fun saveCustomThemes(context: Context, themes: List<ReaderTheme>) {
+    val prefs = context.getSharedPreferences("reader_prefs", Context.MODE_PRIVATE)
+    val jsonArray = JSONArray()
+    themes.filter { it.isCustom }.forEach { theme ->
+        val obj = JSONObject().apply {
+            put("id", theme.id)
+            put("name", theme.name)
+            put("bgColor", theme.backgroundColor.toArgb())
+            put("textColor", theme.textColor.toArgb())
+            put("isDark", theme.isDark)
+            theme.textureId?.let { put("textureId", it) }
+        }
+        jsonArray.put(obj)
+    }
+    prefs.edit { putString(PREF_CUSTOM_THEMES, jsonArray.toString()) }
+}
+
+fun loadCustomThemes(context: Context): List<ReaderTheme> {
+    val prefs = context.getSharedPreferences("reader_prefs", Context.MODE_PRIVATE)
+    val jsonString = prefs.getString(PREF_CUSTOM_THEMES, "[]") ?: "[]"
+    val themes = mutableListOf<ReaderTheme>()
+    try {
+        val jsonArray = org.json.JSONArray(jsonString)
+        for (i in 0 until jsonArray.length()) {
+            val obj = jsonArray.getJSONObject(i)
+            themes.add(
+                ReaderTheme(
+                    id = obj.getString("id"),
+                    name = obj.getString("name"),
+                    backgroundColor = Color(obj.getInt("bgColor")),
+                    textColor = Color(obj.getInt("textColor")),
+                    isDark = obj.getBoolean("isDark"),
+                    textureId = if (obj.has("textureId")) obj.getString("textureId") else null,
+                    isCustom = true
+                )
+            )
+        }
+    } catch (e: Exception) {
+        Timber.e(e, "Failed to parse custom themes")
+    }
+    return themes
+}
+
+private fun calculateContrastRatio(color1: Color, color2: Color): Float {
+    val l1 = max(color1.luminance(), color2.luminance())
+    val l2 = min(color1.luminance(), color2.luminance())
+    return (l1 + 0.05f) / (l2 + 0.05f)
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun ReaderThemePanel(
+    isVisible: Boolean,
+    currentThemeId: String,
+    customThemes: List<ReaderTheme>,
+    builtInThemes: List<ReaderTheme> = BuiltInThemes,
+    onThemeSelected: (String) -> Unit,
+    onCustomThemesUpdated: (List<ReaderTheme>) -> Unit,
+    onDismiss: () -> Unit
+) {
+    if (!isVisible) return
+    var showBuilder by remember { mutableStateOf(false) }
+    var editingTheme by remember { mutableStateOf<ReaderTheme?>(null) }
+
+    val sheetState = rememberModalBottomSheetState(skipPartiallyExpanded = true)
+
+    ModalBottomSheet(
+        onDismissRequest = onDismiss,
+        sheetState = sheetState,
+        containerColor = MaterialTheme.colorScheme.surface,
+        contentWindowInsets = { WindowInsets.navigationBars }
+    ) {
+        AnimatedContent(targetState = showBuilder, label = "ThemePanelTransition") { isBuilding ->
+            if (isBuilding) {
+                ThemeBuilderView(
+                    initialTheme = editingTheme,
+                    onSave = { newTheme ->
+                        val updatedList = if (editingTheme != null) {
+                            customThemes.map { if (it.id == newTheme.id) newTheme else it }
+                        } else {
+                            customThemes + newTheme
+                        }
+                        onCustomThemesUpdated(updatedList)
+                        onThemeSelected(newTheme.id)
+                        showBuilder = false
+                        editingTheme = null
+                    },
+                    onCancel = {
+                        showBuilder = false
+                        editingTheme = null
+                    }
+                )
+            } else {
+                Column(
+                    modifier = Modifier
+                        .fillMaxWidth()
+                        .fillMaxHeight(0.65f)
+                        .padding(16.dp)
+                        .padding(bottom = 16.dp)
+                ) {
+                    Text(
+                        "Reading Themes",
+                        style = MaterialTheme.typography.titleLarge,
+                        fontWeight = FontWeight.Bold,
+                        modifier = Modifier.padding(bottom = 16.dp)
+                    )
+
+                    Text("Presets", style = MaterialTheme.typography.labelLarge, color = MaterialTheme.colorScheme.primary)
+                    Spacer(Modifier.height(8.dp))
+                    ThemeGrid(themes = builtInThemes, currentThemeId = currentThemeId, onThemeSelected = onThemeSelected)
+
+                    Spacer(Modifier.height(24.dp))
+                    Row(
+                        modifier = Modifier.fillMaxWidth(),
+                        horizontalArrangement = Arrangement.SpaceBetween,
+                        verticalAlignment = Alignment.CenterVertically
+                    ) {
+                        Text("My Themes", style = MaterialTheme.typography.labelLarge, color = MaterialTheme.colorScheme.primary)
+                        IconButton(onClick = { editingTheme = null; showBuilder = true }, modifier = Modifier.size(24.dp)) {
+                            Icon(Icons.Default.Add, contentDescription = "Create Theme", tint = MaterialTheme.colorScheme.primary)
+                        }
+                    }
+                    Spacer(Modifier.height(8.dp))
+
+                    if (customThemes.isEmpty()) {
+                        Text("No custom themes yet. Tap '+' to create one.", style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant)
+                    } else {
+                        ThemeGrid(
+                            themes = customThemes,
+                            currentThemeId = currentThemeId,
+                            onThemeSelected = onThemeSelected,
+                            onEdit = { editingTheme = it; showBuilder = true },
+                            onDelete = { themeToDelete ->
+                                val updated = customThemes.filter { it.id != themeToDelete.id }
+                                onCustomThemesUpdated(updated)
+                                if (currentThemeId == themeToDelete.id) onThemeSelected("system")
+                            }
+                        )
+                    }
+                }
+            }
+        }
+    }
+}
+
+@Composable
+fun ThemeGrid(
+    themes: List<ReaderTheme>,
+    currentThemeId: String,
+    onThemeSelected: (String) -> Unit,
+    onEdit: ((ReaderTheme) -> Unit)? = null,
+    onDelete: ((ReaderTheme) -> Unit)? = null
+) {
+    androidx.compose.foundation.lazy.grid.LazyVerticalGrid(
+        columns = androidx.compose.foundation.lazy.grid.GridCells.Adaptive(minSize = 80.dp),
+        horizontalArrangement = Arrangement.spacedBy(8.dp),
+        verticalArrangement = Arrangement.spacedBy(16.dp)
+    ) {
+        items(themes.size) { index ->
+            val theme = themes[index]
+            val isSelected = currentThemeId == theme.id
+            val bgColor = if (theme.id == "system") MaterialTheme.colorScheme.surfaceVariant else theme.backgroundColor
+            val textColor = if (theme.id == "system") MaterialTheme.colorScheme.onSurfaceVariant else theme.textColor
+            val borderColor = if (isSelected) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.outlineVariant
+
+            Column(
+                horizontalAlignment = Alignment.CenterHorizontally,
+            ) {
+                Box(
+                    modifier = Modifier
+                        .size(56.dp)
+                        .background(bgColor, CircleShape)
+                        .border(if (isSelected) 3.dp else 1.dp, borderColor, CircleShape)
+                        .clickable { onThemeSelected(theme.id) },
+                    contentAlignment = Alignment.Center
+                ) {
+                    Text(text = "Aa", color = textColor, style = MaterialTheme.typography.bodyMedium, fontWeight = FontWeight.Bold)
+                }
+                Spacer(modifier = Modifier.height(8.dp))
+                Text(text = theme.name, style = MaterialTheme.typography.labelSmall, color = if (isSelected) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.onSurface, maxLines = 1, overflow = TextOverflow.Ellipsis)
+
+                if (theme.isCustom && onEdit != null && onDelete != null) {
+                    Spacer(modifier = Modifier.height(6.dp))
+                    Surface(
+                        shape = RoundedCornerShape(16.dp),
+                        color = MaterialTheme.colorScheme.surfaceVariant,
+                    ) {
+                        Row(
+                            modifier = Modifier.padding(horizontal = 6.dp, vertical = 4.dp),
+                            horizontalArrangement = Arrangement.Center,
+                            verticalAlignment = Alignment.CenterVertically
+                        ) {
+                            Icon(Icons.Default.Edit, "Edit", Modifier.size(28.dp).clip(CircleShape).clickable { onEdit(theme) }.padding(6.dp), tint = MaterialTheme.colorScheme.primary)
+                            Spacer(Modifier.width(4.dp))
+                            Icon(Icons.Default.Delete, "Delete", Modifier.size(28.dp).clip(CircleShape).clickable { onDelete(theme) }.padding(6.dp), tint = MaterialTheme.colorScheme.error)
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+@Composable
+fun ThemeBuilderView(
+    initialTheme: ReaderTheme?,
+    onSave: (ReaderTheme) -> Unit,
+    onCancel: () -> Unit
+) {
+    var name by remember { mutableStateOf(initialTheme?.name ?: "Custom Theme") }
+    var bgColor by remember { mutableStateOf(initialTheme?.backgroundColor ?: Color(0xFFF5F5F5)) }
+    var txtColor by remember { mutableStateOf(initialTheme?.textColor ?: Color(0xFF111111)) }
+    var textureId by remember { mutableStateOf(initialTheme?.textureId) }
+
+    var editingColorType by remember { mutableStateOf<String?>(null) }
+
+    val contrast = calculateContrastRatio(bgColor, txtColor)
+    val isDark = bgColor.luminance() < 0.5f
+
+    Column(
+        modifier = Modifier
+            .fillMaxWidth()
+            .fillMaxHeight(0.85f)
+            .padding(16.dp)
+    ) {
+        Text(
+            text = if (initialTheme == null) "New Theme" else "Edit Theme",
+            fontWeight = FontWeight.Bold,
+            style = MaterialTheme.typography.titleLarge,
+            color = MaterialTheme.colorScheme.onSurface
+        )
+
+        Spacer(Modifier.height(16.dp))
+
+        Column(modifier = Modifier.weight(1f).verticalScroll(rememberScrollState())) {
+            androidx.compose.material3.OutlinedTextField(
+                value = name,
+                onValueChange = { name = it },
+                label = { Text("Theme Name") },
+                modifier = Modifier.fillMaxWidth().padding(vertical = 8.dp),
+                singleLine = true
+            )
+
+            // Live Preview Card
+            Surface(
+                modifier = Modifier.fillMaxWidth().height(120.dp).padding(vertical = 8.dp),
+                shape = RoundedCornerShape(12.dp),
+                color = bgColor,
+                border = BorderStroke(1.dp, MaterialTheme.colorScheme.outlineVariant)
+            ) {
+                val context = LocalContext.current
+                Box(modifier = Modifier.fillMaxSize().run {
+                    val texRes = ReaderTexture.entries.find { it.id == textureId }?.resId
+                    if (texRes != null) {
+                        val bmp = ImageBitmap.imageResource(context.resources, texRes)
+                        this.drawBehind {
+                            drawRect(ShaderBrush(ImageShader(bmp, TileMode.Repeated, TileMode.Repeated)), blendMode = BlendMode.Multiply, alpha = 0.5f)
+                        }
+                    } else this
+                }) {
+                    Column(Modifier.padding(16.dp).fillMaxWidth()) {
+                        Text(
+                            text = "So many books, so little time.",
+                            color = txtColor,
+                            style = MaterialTheme.typography.titleMedium
+                        )
+                        Spacer(Modifier.height(8.dp))
+                        Text(
+                            text = "- Frank Zappa",
+                            color = txtColor,
+                            style = MaterialTheme.typography.bodyMedium,
+                            modifier = Modifier.fillMaxWidth(),
+                            textAlign = TextAlign.End
+                        )
+                    }
+                }
+            }
+
+            // Animated Contrast Warning
+            AnimatedVisibility(visible = contrast < 4.5f) {
+                Text(
+                    "⚠️ Low contrast! This might cause eye strain.",
+                    color = MaterialTheme.colorScheme.error,
+                    style = MaterialTheme.typography.labelSmall,
+                    modifier = Modifier.padding(bottom = 8.dp)
+                )
+            }
+
+            Spacer(Modifier.height(16.dp))
+
+            // Sleek Color Swatches
+            Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(16.dp)) {
+                ColorSwatchItem(
+                    label = "Page Color",
+                    color = bgColor,
+                    onClick = { editingColorType = "bg" },
+                    modifier = Modifier.weight(1f)
+                )
+                ColorSwatchItem(
+                    label = "Text Color",
+                    color = txtColor,
+                    onClick = { editingColorType = "text" },
+                    modifier = Modifier.weight(1f)
+                )
+            }
+            Spacer(Modifier.height(16.dp))
+        }
+
+        // Action Buttons at the bottom for better visibility
+        Row(
+            modifier = Modifier.fillMaxWidth().padding(top = 16.dp),
+            horizontalArrangement = Arrangement.End,
+            verticalAlignment = Alignment.CenterVertically
+        ) {
+            TextButton(onClick = onCancel) {
+                Text("Cancel", color = MaterialTheme.colorScheme.primary)
+            }
+            Spacer(Modifier.width(8.dp))
+            Button(onClick = {
+                onSave(ReaderTheme(id = initialTheme?.id ?: System.currentTimeMillis().toString(), name = name, backgroundColor = bgColor, textColor = txtColor, isDark = isDark, textureId = textureId, isCustom = true))
+            }) {
+                Text("Save", color = MaterialTheme.colorScheme.onPrimary)
+            }
+        }
+    }
+
+    editingColorType?.let { type ->
+        ThemeColorPickerDialog(
+            initialColor = if (type == "bg") bgColor else txtColor,
+            title = if (type == "bg") "Page Color" else "Text Color",
+            bgColor = bgColor,
+            textColor = txtColor,
+            editingColorType = type,
+            onDismiss = { editingColorType = null },
+            onColorChanged = { newColor ->
+                if (type == "bg") bgColor = newColor else txtColor = newColor
+            }
+        )
+    }
+}
+
+@OptIn(ExperimentalMaterial3Api::class)
+@Composable
+fun ColorSwatchItem(label: String, color: Color, onClick: () -> Unit, modifier: Modifier = Modifier) {
+    Column(modifier = modifier) {
+        Text(label, style = MaterialTheme.typography.labelMedium, modifier = Modifier.padding(bottom = 8.dp))
+        Surface(
+            onClick = onClick,
+            shape = RoundedCornerShape(12.dp),
+            color = color,
+            border = BorderStroke(1.dp, MaterialTheme.colorScheme.outlineVariant),
+            modifier = Modifier.fillMaxWidth().height(56.dp)
+        ) {}
+    }
+}
+
+@Composable
+fun ThemeColorPickerDialog(
+    initialColor: Color,
+    title: String,
+    bgColor: Color,
+    textColor: Color,
+    editingColorType: String,
+    onDismiss: () -> Unit,
+    onColorChanged: (Color) -> Unit
+) {
+    val initialHsv = remember(initialColor) {
+        val hsv = FloatArray(3)
+        android.graphics.Color.colorToHSV(initialColor.toArgb(), hsv)
+        hsv
+    }
+
+    var hue by remember { mutableFloatStateOf(initialHsv[0]) }
+    var saturation by remember { mutableFloatStateOf(initialHsv[1]) }
+    var value by remember { mutableFloatStateOf(initialHsv[2]) }
+
+    val currentColor by remember {
+        derivedStateOf {
+            val hsv = floatArrayOf(hue, saturation, value)
+            val argb = android.graphics.Color.HSVToColor(255, hsv)
+            Color(argb)
+        }
+    }
+
+    LaunchedEffect(currentColor) {
+        onColorChanged(currentColor)
+    }
+
+    fun updateFromColor(color: Color) {
+        val hsv = FloatArray(3)
+        android.graphics.Color.colorToHSV(color.toArgb(), hsv)
+        hue = hsv[0]
+        saturation = hsv[1]
+        value = hsv[2]
+    }
+
+    androidx.compose.ui.window.Dialog(
+        onDismissRequest = onDismiss,
+        properties = androidx.compose.ui.window.DialogProperties(usePlatformDefaultWidth = false)
+    ) {
+        Surface(
+            shape = RoundedCornerShape(24.dp),
+            color = Color(0xFF2C2C2C),
+            modifier = Modifier
+                .fillMaxWidth(0.9f)
+                .padding(16.dp)
+        ) {
+            Column(
+                modifier = Modifier
+                    .padding(20.dp)
+                    .verticalScroll(rememberScrollState()), // Prevents elements from hiding off-screen
+                horizontalAlignment = Alignment.CenterHorizontally
+            ) {
+                Box(
+                    modifier = Modifier
+                        .background(Color(0xFF3E3E3E), RoundedCornerShape(16.dp))
+                        .padding(horizontal = 24.dp, vertical = 8.dp)
+                ) {
+                    Text(
+                        text = title,
+                        style = MaterialTheme.typography.titleMedium,
+                        fontWeight = FontWeight.SemiBold,
+                        color = Color.White
+                    )
+                }
+
+                Spacer(Modifier.height(16.dp))
+
+                val liveBgColor = if (editingColorType == "bg") currentColor else bgColor
+                val liveTextColor = if (editingColorType == "text") currentColor else textColor
+
+                Surface(
+                    modifier = Modifier.fillMaxWidth().height(64.dp),
+                    shape = RoundedCornerShape(12.dp),
+                    color = liveBgColor,
+                    border = BorderStroke(1.dp, MaterialTheme.colorScheme.outlineVariant)
+                ) {
+                    Column(Modifier.fillMaxSize(), verticalArrangement = Arrangement.Center, horizontalAlignment = Alignment.CenterHorizontally) {
+                        Text(
+                            text = "Live Preview",
+                            color = liveTextColor,
+                            style = MaterialTheme.typography.bodyMedium,
+                            fontWeight = FontWeight.Bold
+                        )
+                        Text(
+                            text = "Reading is dreaming.",
+                            color = liveTextColor,
+                            style = MaterialTheme.typography.bodySmall
+                        )
+                    }
+                }
+
+                Spacer(Modifier.height(20.dp))
+
+                SpectrumBox(
+                    hue = hue,
+                    saturation = saturation,
+                    currentColor = currentColor,
+                    onHueSatChanged = { h, s -> hue = h; saturation = s },
+                    modifier = Modifier.fillMaxWidth().height(220.dp)
+                )
+
+                Spacer(Modifier.height(20.dp))
+
+                BrightnessSlider(
+                    hue = hue,
+                    saturation = saturation,
+                    value = value,
+                    onValueChanged = { value = it },
+                    modifier = Modifier.fillMaxWidth().height(24.dp).clip(RoundedCornerShape(12.dp))
+                )
+
+                Spacer(Modifier.height(24.dp))
+
+                Row(
+                    modifier = Modifier.fillMaxWidth(),
+                    verticalAlignment = Alignment.Bottom,
+                    horizontalArrangement = Arrangement.spacedBy(12.dp)
+                ) {
+                    ColorComparePill(
+                        oldColor = initialColor,
+                        newColor = currentColor,
+                        modifier = Modifier.width(64.dp).height(36.dp)
+                    )
+
+                    Column(
+                        modifier = Modifier.weight(1.6f),
+                        horizontalAlignment = Alignment.CenterHorizontally
+                    ) {
+                        Text("Hex", color = Color.Gray, fontSize = 12.sp, maxLines = 1)
+                        Spacer(Modifier.height(4.dp))
+                        HexInput(color = currentColor, onHexChanged = { updateFromColor(it) })
+                    }
+
+                    Row(
+                        modifier = Modifier.weight(2.4f),
+                        horizontalArrangement = Arrangement.spacedBy(6.dp)
+                    ) {
+                        RgbInputColumn(
+                            label = "R", value = currentColor.red,
+                            onValueChange = { r -> updateFromColor(currentColor.copy(red = r)) },
+                            modifier = Modifier.weight(1f)
+                        )
+                        RgbInputColumn(
+                            label = "G", value = currentColor.green,
+                            onValueChange = { g -> updateFromColor(currentColor.copy(green = g)) },
+                            modifier = Modifier.weight(1f)
+                        )
+                        RgbInputColumn(
+                            label = "B", value = currentColor.blue,
+                            onValueChange = { b -> updateFromColor(currentColor.copy(blue = b)) },
+                            modifier = Modifier.weight(1f)
+                        )
+                    }
+                }
+
+                Spacer(Modifier.height(24.dp))
+
+                Row(
+                    modifier = Modifier.fillMaxWidth(),
+                    horizontalArrangement = Arrangement.End,
+                    verticalAlignment = Alignment.CenterVertically
+                ) {
+                    Button(
+                        onClick = onDismiss,
+                        colors = androidx.compose.material3.ButtonDefaults.buttonColors(
+                            containerColor = Color.White
+                        )
+                    ) {
+                        Text("Save", color = Color.Black, fontWeight = FontWeight.Bold)
+                    }
+                }
+            }
+        }
+    }
+}
+
+@Composable
+fun TextureOption(name: String, resId: Int?, isSelected: Boolean, onClick: () -> Unit) {
+    Column(horizontalAlignment = Alignment.CenterHorizontally, modifier = Modifier.clickable(onClick = onClick)) {
+        Box(modifier = Modifier.size(48.dp).clip(CircleShape).border(if (isSelected) 3.dp else 1.dp, if (isSelected) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.outlineVariant, CircleShape).run {
+            if (resId != null) {
+                val bmp = ImageBitmap.imageResource(LocalResources.current, resId)
+                this.drawBehind { drawRect(ShaderBrush(ImageShader(bmp, TileMode.Repeated, TileMode.Repeated))) }
+            } else this.background(MaterialTheme.colorScheme.surfaceVariant)
+        })
+        Text(name, style = MaterialTheme.typography.labelSmall, modifier = Modifier.padding(top = 4.dp))
+    }
+}
+
+@Composable
+fun ColorSlider(color: Color, onColorChanged: (Color) -> Unit) {
+    Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(8.dp)) {
+        Slider(value = color.red, onValueChange = { onColorChanged(color.copy(red = it)) }, colors = androidx.compose.material3.SliderDefaults.colors(thumbColor = Color.Red, activeTrackColor = Color.Red), modifier = Modifier.weight(1f))
+        Slider(value = color.green, onValueChange = { onColorChanged(color.copy(green = it)) }, colors = androidx.compose.material3.SliderDefaults.colors(thumbColor = Color.Green, activeTrackColor = Color.Green), modifier = Modifier.weight(1f))
+        Slider(value = color.blue, onValueChange = { onColorChanged(color.copy(blue = it)) }, colors = androidx.compose.material3.SliderDefaults.colors(thumbColor = Color.Blue, activeTrackColor = Color.Blue), modifier = Modifier.weight(1f))
+    }
 }

app/src/main/java/com/aryan/reader/epubreader/ChapterWebView.kt

@@ -81,6 +81,7 @@ import androidx.compose.ui.viewinterop.AndroidView
 import androidx.compose.ui.window.Popup
 import androidx.compose.ui.window.PopupPositionProvider
 import androidx.core.net.toUri
+import com.aryan.reader.ReaderTexture
 import com.aryan.reader.paginatedreader.PaginatedTextSelectionMenu
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.launch

app/src/main/java/com/aryan/reader/epubreader/EpubReaderScreen.kt

@@ -29,11 +29,6 @@ import android.annotation.SuppressLint
 import android.app.Activity
 import android.content.Context
 import android.content.pm.PackageManager
-import com.aryan.reader.SpectrumBox
-import com.aryan.reader.BrightnessSlider
-import com.aryan.reader.ColorComparePill
-import com.aryan.reader.HexInput
-import com.aryan.reader.RgbInputColumn
 import android.graphics.Bitmap
 import android.media.AudioManager
 import android.net.Uri
@@ -53,7 +48,6 @@ import androidx.compose.animation.fadeOut
 import androidx.compose.animation.slideInVertically
 import androidx.compose.animation.slideOutVertically
 import androidx.compose.animation.togetherWith
-import androidx.compose.foundation.BorderStroke
 import androidx.compose.foundation.background
 import androidx.compose.foundation.border
 import androidx.compose.foundation.clickable
@@ -62,11 +56,9 @@ import androidx.compose.foundation.gestures.awaitEachGesture
 import androidx.compose.foundation.gestures.awaitFirstDown
 import androidx.compose.foundation.gestures.waitForUpOrCancellation
 import androidx.compose.foundation.isSystemInDarkTheme
-import androidx.compose.foundation.layout.Arrangement
 import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.BoxWithConstraints
 import androidx.compose.foundation.layout.Column
-import androidx.compose.foundation.layout.Row
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.WindowInsets
 import androidx.compose.foundation.layout.asPaddingValues
@@ -79,35 +71,26 @@ import androidx.compose.foundation.layout.offset
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.statusBars
-import androidx.compose.foundation.layout.width
 import androidx.compose.foundation.layout.windowInsetsBottomHeight
 import androidx.compose.foundation.layout.windowInsetsEndWidth
 import androidx.compose.foundation.layout.windowInsetsStartWidth
 import androidx.compose.foundation.pager.rememberPagerState
-import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
-import androidx.compose.material.icons.filled.Add
 import androidx.compose.material.icons.filled.ArrowDownward
 import androidx.compose.material.icons.filled.ArrowUpward
-import androidx.compose.material.icons.filled.Delete
-import androidx.compose.material.icons.filled.Edit
 import androidx.compose.material.icons.filled.Info
 import androidx.compose.material3.AlertDialog
-import androidx.compose.material3.Button
 import androidx.compose.material3.CircularProgressIndicator
 import androidx.compose.material3.DrawerValue
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Icon
-import androidx.compose.material3.IconButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.ModalBottomSheet
 import androidx.compose.material3.ModalNavigationDrawer
 import androidx.compose.material3.Scaffold
-import androidx.compose.material3.Slider
 import androidx.compose.material3.SnackbarHost
 import androidx.compose.material3.SnackbarHostState
-import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
 import androidx.compose.material3.rememberDrawerState
@@ -133,32 +116,19 @@ import androidx.compose.ui.Alignment
 import androidx.compose.ui.BiasAlignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.alpha
-import androidx.compose.ui.draw.clip
-import androidx.compose.ui.draw.drawBehind
 import androidx.compose.ui.focus.FocusRequester
 import androidx.compose.ui.focus.focusRequester
-import androidx.compose.ui.graphics.BlendMode
 import androidx.compose.ui.graphics.Color
-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.luminance
-import androidx.compose.ui.graphics.toArgb
 import androidx.compose.ui.input.pointer.pointerInput
 import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.platform.LocalDensity
 import androidx.compose.ui.platform.LocalFocusManager
-import androidx.compose.ui.platform.LocalResources
 import androidx.compose.ui.platform.LocalSoftwareKeyboardController
 import androidx.compose.ui.platform.LocalView
 import androidx.compose.ui.platform.testTag
-import androidx.compose.ui.res.imageResource
-import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.dp
-import androidx.compose.ui.unit.sp
 import androidx.core.content.ContextCompat
 import androidx.core.content.edit
 import androidx.core.view.WindowCompat
@@ -170,10 +140,11 @@ import androidx.media3.common.util.UnstableApi
 import com.aryan.reader.AiDefinitionResult
 import com.aryan.reader.BannerMessage
 import com.aryan.reader.BuildConfig
+import com.aryan.reader.BuiltInThemes
 import com.aryan.reader.CustomTopBanner
 import com.aryan.reader.DeviceVoiceSettingsSheet
 import com.aryan.reader.MainViewModel
-import com.aryan.reader.R
+import com.aryan.reader.ReaderThemePanel
 import com.aryan.reader.RenderMode
 import com.aryan.reader.SearchResult
 import com.aryan.reader.SummarizationResult
@@ -183,6 +154,8 @@ import com.aryan.reader.countWords
 import com.aryan.reader.data.CustomFontEntity
 import com.aryan.reader.epub.EpubBook
 import com.aryan.reader.fetchAiDefinition
+import com.aryan.reader.loadCustomThemes
+import com.aryan.reader.loadReaderThemeId
 import com.aryan.reader.paginatedreader.BookPaginator
 import com.aryan.reader.paginatedreader.HeaderBlock
 import com.aryan.reader.paginatedreader.IPaginator
@@ -197,6 +170,8 @@ import com.aryan.reader.paginatedreader.TtsChunk
 import com.aryan.reader.paginatedreader.data.BookCacheDatabase
 import com.aryan.reader.paginatedreader.semanticBlockModule
 import com.aryan.reader.rememberSearchState
+import com.aryan.reader.saveCustomThemes
+import com.aryan.reader.saveReaderThemeId
 import com.aryan.reader.tts.SpeakerSamplePlayer
 import com.aryan.reader.tts.loadTtsMode
 import com.aryan.reader.tts.rememberTtsController
@@ -366,93 +341,8 @@ private fun saveExternalSearchPackage(context: Context, packageName: String) {
     prefs.edit { putString(PREF_EXTERNAL_SEARCH_PKG, packageName) }
 }
 
-enum class ReaderTexture(val id: String, val resId: Int, val displayName: String) {
+const val PREF_READER_THEME = "reader_theme_id"
-    PAPER("paper", R.drawable.texture_paper, "Paper"),
+const val PREF_CUSTOM_THEMES = "custom_themes_json"
-    CANVAS("canvas", R.drawable.texture_canvas, "Canvas"),
-    EINK("eink", R.drawable.texture_eink, "E-Ink"),
-    SLATE("slate", R.drawable.texture_slate, "Slate")
-}
-
-data class ReaderTheme(
-    val id: String,
-    val name: String,
-    val backgroundColor: Color,
-    val textColor: Color,
-    val isDark: Boolean,
-    val textureId: String? = null,
-    val isCustom: Boolean = false
-)
-
-val BuiltInThemes = listOf(
-    ReaderTheme("system", "System", Color.Unspecified, Color.Unspecified, false),
-    ReaderTheme("light", "Light", Color(0xFFFFFFFF), Color(0xFF000000), false),
-    ReaderTheme("dark", "Dark", Color(0xFF121212), Color(0xFFE0E0E0), true),
-    ReaderTheme("sepia", "Sepia", Color(0xFFFBF0D9), Color(0xFF5F4B32), false),
-    ReaderTheme("slate", "Slate", Color(0xFF2E3440), Color(0xFFECEFF4), true),
-    ReaderTheme("oled", "OLED", Color(0xFF000000), Color(0xFFB0B0B0), true)
-)
-
-private const val PREF_READER_THEME = "reader_theme_id"
-private const val PREF_CUSTOM_THEMES = "custom_themes_json"
-
-private fun saveReaderThemeId(context: Context, themeId: String) {
-    val prefs = context.getSharedPreferences("reader_prefs", Context.MODE_PRIVATE)
-    prefs.edit { putString(PREF_READER_THEME, themeId) }
-}
-
-private fun loadReaderThemeId(context: Context): String {
-    val prefs = context.getSharedPreferences("reader_prefs", Context.MODE_PRIVATE)
-    return prefs.getString(PREF_READER_THEME, "system") ?: "system"
-}
-
-private fun saveCustomThemes(context: Context, themes: List<ReaderTheme>) {
-    val prefs = context.getSharedPreferences("reader_prefs", Context.MODE_PRIVATE)
-    val jsonArray = JSONArray()
-    themes.filter { it.isCustom }.forEach { theme ->
-        val obj = JSONObject().apply {
-            put("id", theme.id)
-            put("name", theme.name)
-            put("bgColor", theme.backgroundColor.toArgb())
-            put("textColor", theme.textColor.toArgb())
-            put("isDark", theme.isDark)
-            theme.textureId?.let { put("textureId", it) }
-        }
-        jsonArray.put(obj)
-    }
-    prefs.edit { putString(PREF_CUSTOM_THEMES, jsonArray.toString()) }
-}
-
-private fun loadCustomThemes(context: Context): List<ReaderTheme> {
-    val prefs = context.getSharedPreferences("reader_prefs", Context.MODE_PRIVATE)
-    val jsonString = prefs.getString(PREF_CUSTOM_THEMES, "[]") ?: "[]"
-    val themes = mutableListOf<ReaderTheme>()
-    try {
-        val jsonArray = org.json.JSONArray(jsonString)
-        for (i in 0 until jsonArray.length()) {
-            val obj = jsonArray.getJSONObject(i)
-            themes.add(
-                ReaderTheme(
-                    id = obj.getString("id"),
-                    name = obj.getString("name"),
-                    backgroundColor = Color(obj.getInt("bgColor")),
-                    textColor = Color(obj.getInt("textColor")),
-                    isDark = obj.getBoolean("isDark"),
-                    textureId = if (obj.has("textureId")) obj.getString("textureId") else null,
-                    isCustom = true
-                )
-            )
-        }
-    } catch (e: Exception) {
-        Timber.e(e, "Failed to parse custom themes")
-    }
-    return themes
-}
-
-private fun calculateContrastRatio(color1: Color, color2: Color): Float {
-    val l1 = max(color1.luminance(), color2.luminance())
-    val l2 = min(color1.luminance(), color2.luminance())
-    return (l1 + 0.05f) / (l2 + 0.05f)
-}
 
 @RequiresApi(Build.VERSION_CODES.VANILLA_ICE_CREAM)
 @Composable
@@ -4038,500 +3928,4 @@ fun EpubReaderHost(
             )
         }
     }
-}
-
-@OptIn(ExperimentalMaterial3Api::class)
-@Composable
-fun ReaderThemePanel(
-    isVisible: Boolean,
-    currentThemeId: String,
-    customThemes: List<ReaderTheme>,
-    onThemeSelected: (String) -> Unit,
-    onCustomThemesUpdated: (List<ReaderTheme>) -> Unit,
-    onDismiss: () -> Unit
-) {
-    if (!isVisible) return
-    var showBuilder by remember { mutableStateOf(false) }
-    var editingTheme by remember { mutableStateOf<ReaderTheme?>(null) }
-
-    val sheetState = rememberModalBottomSheetState(skipPartiallyExpanded = true)
-
-    ModalBottomSheet(
-        onDismissRequest = onDismiss,
-        sheetState = sheetState,
-        containerColor = MaterialTheme.colorScheme.surface,
-        contentWindowInsets = { WindowInsets.navigationBars }
-    ) {
-        AnimatedContent(targetState = showBuilder, label = "ThemePanelTransition") { isBuilding ->
-            if (isBuilding) {
-                ThemeBuilderView(
-                    initialTheme = editingTheme,
-                    onSave = { newTheme ->
-                        val updatedList = if (editingTheme != null) {
-                            customThemes.map { if (it.id == newTheme.id) newTheme else it }
-                        } else {
-                            customThemes + newTheme
-                        }
-                        onCustomThemesUpdated(updatedList)
-                        onThemeSelected(newTheme.id)
-                        showBuilder = false
-                        editingTheme = null
-                    },
-                    onCancel = {
-                        showBuilder = false
-                        editingTheme = null
-                    }
-                )
-            } else {
-                Column(
-                    modifier = Modifier
-                        .fillMaxWidth()
-                        .fillMaxHeight(0.65f)
-                        .padding(16.dp)
-                        .padding(bottom = 16.dp)
-                ) {
-                    Text(
-                        "Reading Themes",
-                        style = MaterialTheme.typography.titleLarge,
-                        fontWeight = FontWeight.Bold,
-                        modifier = Modifier.padding(bottom = 16.dp)
-                    )
-
-                    Text("Presets", style = MaterialTheme.typography.labelLarge, color = MaterialTheme.colorScheme.primary)
-                    Spacer(Modifier.height(8.dp))
-                    ThemeGrid(themes = BuiltInThemes, currentThemeId = currentThemeId, onThemeSelected = onThemeSelected)
-
-                    Spacer(Modifier.height(24.dp))
-                    Row(
-                        modifier = Modifier.fillMaxWidth(),
-                        horizontalArrangement = Arrangement.SpaceBetween,
-                        verticalAlignment = Alignment.CenterVertically
-                    ) {
-                        Text("My Themes", style = MaterialTheme.typography.labelLarge, color = MaterialTheme.colorScheme.primary)
-                        IconButton(onClick = { editingTheme = null; showBuilder = true }, modifier = Modifier.size(24.dp)) {
-                            Icon(Icons.Default.Add, contentDescription = "Create Theme", tint = MaterialTheme.colorScheme.primary)
-                        }
-                    }
-                    Spacer(Modifier.height(8.dp))
-
-                    if (customThemes.isEmpty()) {
-                        Text("No custom themes yet. Tap '+' to create one.", style = MaterialTheme.typography.bodySmall, color = MaterialTheme.colorScheme.onSurfaceVariant)
-                    } else {
-                        ThemeGrid(
-                            themes = customThemes,
-                            currentThemeId = currentThemeId,
-                            onThemeSelected = onThemeSelected,
-                            onEdit = { editingTheme = it; showBuilder = true },
-                            onDelete = { themeToDelete ->
-                                val updated = customThemes.filter { it.id != themeToDelete.id }
-                                onCustomThemesUpdated(updated)
-                                if (currentThemeId == themeToDelete.id) onThemeSelected("system")
-                            }
-                        )
-                    }
-                }
-            }
-        }
-    }
-}
-
-@Composable
-fun ThemeGrid(
-    themes: List<ReaderTheme>,
-    currentThemeId: String,
-    onThemeSelected: (String) -> Unit,
-    onEdit: ((ReaderTheme) -> Unit)? = null,
-    onDelete: ((ReaderTheme) -> Unit)? = null
-) {
-    androidx.compose.foundation.lazy.grid.LazyVerticalGrid(
-        columns = androidx.compose.foundation.lazy.grid.GridCells.Adaptive(minSize = 80.dp),
-        horizontalArrangement = Arrangement.spacedBy(8.dp),
-        verticalArrangement = Arrangement.spacedBy(16.dp)
-    ) {
-        items(themes.size) { index ->
-            val theme = themes[index]
-            val isSelected = currentThemeId == theme.id
-            val bgColor = if (theme.id == "system") MaterialTheme.colorScheme.surfaceVariant else theme.backgroundColor
-            val textColor = if (theme.id == "system") MaterialTheme.colorScheme.onSurfaceVariant else theme.textColor
-            val borderColor = if (isSelected) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.outlineVariant
-
-            Column(
-                horizontalAlignment = Alignment.CenterHorizontally,
-            ) {
-                Box(
-                    modifier = Modifier
-                        .size(56.dp)
-                        .background(bgColor, CircleShape)
-                        .border(if (isSelected) 3.dp else 1.dp, borderColor, CircleShape)
-                        .clickable { onThemeSelected(theme.id) },
-                    contentAlignment = Alignment.Center
-                ) {
-                    Text(text = "Aa", color = textColor, style = MaterialTheme.typography.bodyMedium, fontWeight = FontWeight.Bold)
-                }
-                Spacer(modifier = Modifier.height(8.dp))
-                Text(text = theme.name, style = MaterialTheme.typography.labelSmall, color = if (isSelected) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.onSurface, maxLines = 1, overflow = TextOverflow.Ellipsis)
-
-                if (theme.isCustom && onEdit != null && onDelete != null) {
-                    Spacer(modifier = Modifier.height(6.dp))
-                    Surface(
-                        shape = RoundedCornerShape(16.dp),
-                        color = MaterialTheme.colorScheme.surfaceVariant,
-                    ) {
-                        Row(
-                            modifier = Modifier.padding(horizontal = 6.dp, vertical = 4.dp),
-                            horizontalArrangement = Arrangement.Center,
-                            verticalAlignment = Alignment.CenterVertically
-                        ) {
-                            Icon(Icons.Default.Edit, "Edit", Modifier.size(28.dp).clip(CircleShape).clickable { onEdit(theme) }.padding(6.dp), tint = MaterialTheme.colorScheme.primary)
-                            Spacer(Modifier.width(4.dp))
-                            Icon(Icons.Default.Delete, "Delete", Modifier.size(28.dp).clip(CircleShape).clickable { onDelete(theme) }.padding(6.dp), tint = MaterialTheme.colorScheme.error)
-                        }
-                    }
-                }
-            }
-        }
-    }
-}
-
-@Composable
-fun ThemeBuilderView(
-    initialTheme: ReaderTheme?,
-    onSave: (ReaderTheme) -> Unit,
-    onCancel: () -> Unit
-) {
-    var name by remember { mutableStateOf(initialTheme?.name ?: "Custom Theme") }
-    var bgColor by remember { mutableStateOf(initialTheme?.backgroundColor ?: Color(0xFFF5F5F5)) }
-    var txtColor by remember { mutableStateOf(initialTheme?.textColor ?: Color(0xFF111111)) }
-    var textureId by remember { mutableStateOf(initialTheme?.textureId) }
-
-    var editingColorType by remember { mutableStateOf<String?>(null) }
-
-    val contrast = calculateContrastRatio(bgColor, txtColor)
-    val isDark = bgColor.luminance() < 0.5f
-
-    Column(modifier = Modifier.fillMaxWidth().fillMaxHeight(0.65f).padding(16.dp)) {
-        Row(Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.SpaceBetween, verticalAlignment = Alignment.CenterVertically) {
-            TextButton(onClick = onCancel) { Text("Cancel") }
-            Text(if (initialTheme == null) "New Theme" else "Edit Theme", fontWeight = FontWeight.Bold, style = MaterialTheme.typography.titleMedium)
-            TextButton(onClick = {
-                onSave(ReaderTheme(id = initialTheme?.id ?: System.currentTimeMillis().toString(), name = name, backgroundColor = bgColor, textColor = txtColor, isDark = isDark, textureId = textureId, isCustom = true))
-            }) { Text("Save") }
-        }
-
-        androidx.compose.material3.OutlinedTextField(
-            value = name,
-            onValueChange = { name = it },
-            label = { Text("Theme Name") },
-            modifier = Modifier.fillMaxWidth().padding(vertical = 8.dp),
-            singleLine = true
-        )
-
-        // Live Preview Card
-        Surface(
-            modifier = Modifier.fillMaxWidth().height(120.dp).padding(vertical = 8.dp),
-            shape = RoundedCornerShape(12.dp),
-            color = bgColor,
-            border = BorderStroke(1.dp, MaterialTheme.colorScheme.outlineVariant)
-        ) {
-            // Draw Texture if selected (kept logic for future)
-            val context = LocalContext.current
-            Box(modifier = Modifier.fillMaxSize().run {
-                val texRes = ReaderTexture.entries.find { it.id == textureId }?.resId
-                if (texRes != null) {
-                    val bmp = ImageBitmap.imageResource(context.resources, texRes)
-                    this.drawBehind {
-                        drawRect(ShaderBrush(ImageShader(bmp, TileMode.Repeated, TileMode.Repeated)), blendMode = BlendMode.Multiply, alpha = 0.5f)
-                    }
-                } else this
-            }) {
-                Column(Modifier.padding(16.dp).fillMaxWidth()) {
-                    Text(
-                        text = "So many books, so little time.",
-                        color = txtColor,
-                        style = MaterialTheme.typography.titleMedium
-                    )
-                    Spacer(Modifier.height(8.dp))
-                    Text(
-                        text = "- Frank Zappa",
-                        color = txtColor,
-                        style = MaterialTheme.typography.bodyMedium,
-                        modifier = Modifier.fillMaxWidth(),
-                        textAlign = TextAlign.End
-                    )
-                }
-            }
-        }
-
-        // Animated Contrast Warning
-        AnimatedVisibility(visible = contrast < 4.5f) {
-            Text(
-                "⚠️ Low contrast! This might cause eye strain.",
-                color = MaterialTheme.colorScheme.error,
-                style = MaterialTheme.typography.labelSmall,
-                modifier = Modifier.padding(bottom = 8.dp)
-            )
-        }
-
-        Spacer(Modifier.height(16.dp))
-
-        // Sleek Color Swatches
-        Row(modifier = Modifier.fillMaxWidth(), horizontalArrangement = Arrangement.spacedBy(16.dp)) {
-            ColorSwatchItem(
-                label = "Page Color",
-                color = bgColor,
-                onClick = { editingColorType = "bg" },
-                modifier = Modifier.weight(1f)
-            )
-            ColorSwatchItem(
-                label = "Text Color",
-                color = txtColor,
-                onClick = { editingColorType = "text" },
-                modifier = Modifier.weight(1f)
-            )
-        }
-
-        // Texture UI hidden for now
-        /*
-        Spacer(Modifier.height(16.dp))
-        Text("Texture", style = MaterialTheme.typography.labelMedium)
-        Row(Modifier.fillMaxWidth().padding(top = 8.dp), horizontalArrangement = Arrangement.spacedBy(12.dp)) {
-            TextureOption("None", null, textureId == null) { textureId = null }
-            ReaderTexture.entries.forEach { tex ->
-                TextureOption(tex.displayName, tex.resId, textureId == tex.id) { textureId = tex.id }
-            }
-        }
-        */
-        Spacer(Modifier.height(16.dp))
-    }
-
-    editingColorType?.let { type ->
-        ThemeColorPickerDialog(
-            initialColor = if (type == "bg") bgColor else txtColor,
-            title = if (type == "bg") "Page Color" else "Text Color",
-            bgColor = bgColor,
-            textColor = txtColor,
-            editingColorType = type,
-            onDismiss = { editingColorType = null },
-            onColorChanged = { newColor ->
-                if (type == "bg") bgColor = newColor else txtColor = newColor
-            }
-        )
-    }
-}
-
-@OptIn(ExperimentalMaterial3Api::class)
-@Composable
-fun ColorSwatchItem(label: String, color: Color, onClick: () -> Unit, modifier: Modifier = Modifier) {
-    Column(modifier = modifier) {
-        Text(label, style = MaterialTheme.typography.labelMedium, modifier = Modifier.padding(bottom = 8.dp))
-        Surface(
-            onClick = onClick,
-            shape = RoundedCornerShape(12.dp),
-            color = color,
-            border = BorderStroke(1.dp, MaterialTheme.colorScheme.outlineVariant),
-            modifier = Modifier.fillMaxWidth().height(56.dp)
-        ) {}
-    }
-}
-
-@Composable
-fun ThemeColorPickerDialog(
-    initialColor: Color,
-    title: String,
-    bgColor: Color,
-    textColor: Color,
-    editingColorType: String,
-    onDismiss: () -> Unit,
-    onColorChanged: (Color) -> Unit
-) {
-    val initialHsv = remember(initialColor) {
-        val hsv = FloatArray(3)
-        android.graphics.Color.colorToHSV(initialColor.toArgb(), hsv)
-        hsv
-    }
-
-    var hue by remember { mutableFloatStateOf(initialHsv[0]) }
-    var saturation by remember { mutableFloatStateOf(initialHsv[1]) }
-    var value by remember { mutableFloatStateOf(initialHsv[2]) }
-
-    val currentColor by remember {
-        derivedStateOf {
-            val hsv = floatArrayOf(hue, saturation, value)
-            val argb = android.graphics.Color.HSVToColor(255, hsv)
-            Color(argb)
-        }
-    }
-
-    LaunchedEffect(currentColor) {
-        onColorChanged(currentColor)
-    }
-
-    fun updateFromColor(color: Color) {
-        val hsv = FloatArray(3)
-        android.graphics.Color.colorToHSV(color.toArgb(), hsv)
-        hue = hsv[0]
-        saturation = hsv[1]
-        value = hsv[2]
-    }
-
-    androidx.compose.ui.window.Dialog(
-        onDismissRequest = onDismiss,
-        properties = androidx.compose.ui.window.DialogProperties(usePlatformDefaultWidth = false)
-    ) {
-        Surface(
-            shape = RoundedCornerShape(24.dp),
-            color = Color(0xFF2C2C2C),
-            modifier = Modifier
-                .fillMaxWidth(0.85f)
-                .padding(8.dp)
-        ) {
-            Column(
-                modifier = Modifier.padding(20.dp),
-                horizontalAlignment = Alignment.CenterHorizontally
-            ) {
-                Box(
-                    modifier = Modifier
-                        .background(Color(0xFF3E3E3E), RoundedCornerShape(16.dp))
-                        .padding(horizontal = 24.dp, vertical = 8.dp)
-                ) {
-                    Text(
-                        text = title,
-                        style = MaterialTheme.typography.titleMedium,
-                        fontWeight = FontWeight.SemiBold,
-                        color = Color.White
-                    )
-                }
-
-                Spacer(Modifier.height(16.dp))
-
-                val liveBgColor = if (editingColorType == "bg") currentColor else bgColor
-                val liveTextColor = if (editingColorType == "text") currentColor else textColor
-
-                Surface(
-                    modifier = Modifier.fillMaxWidth().height(64.dp),
-                    shape = RoundedCornerShape(12.dp),
-                    color = liveBgColor,
-                    border = BorderStroke(1.dp, MaterialTheme.colorScheme.outlineVariant)
-                ) {
-                    Column(Modifier.fillMaxSize(), verticalArrangement = Arrangement.Center, horizontalAlignment = Alignment.CenterHorizontally) {
-                        Text(
-                            text = "Live Preview",
-                            color = liveTextColor,
-                            style = MaterialTheme.typography.bodyMedium,
-                            fontWeight = FontWeight.Bold
-                        )
-                        Text(
-                            text = "Reading is dreaming.",
-                            color = liveTextColor,
-                            style = MaterialTheme.typography.bodySmall
-                        )
-                    }
-                }
-
-                Spacer(Modifier.height(20.dp))
-
-                SpectrumBox(
-                    hue = hue,
-                    saturation = saturation,
-                    currentColor = currentColor,
-                    onHueSatChanged = { h, s -> hue = h; saturation = s },
-                    modifier = Modifier.fillMaxWidth().height(220.dp)
-                )
-
-                Spacer(Modifier.height(20.dp))
-
-                BrightnessSlider(
-                    hue = hue,
-                    saturation = saturation,
-                    value = value,
-                    onValueChanged = { value = it },
-                    modifier = Modifier.fillMaxWidth().height(24.dp).clip(RoundedCornerShape(12.dp))
-                )
-
-                Spacer(Modifier.height(24.dp))
-
-                Row(
-                    modifier = Modifier.fillMaxWidth(),
-                    verticalAlignment = Alignment.Bottom,
-                    horizontalArrangement = Arrangement.spacedBy(12.dp)
-                ) {
-                    ColorComparePill(
-                        oldColor = initialColor,
-                        newColor = currentColor,
-                        modifier = Modifier.width(64.dp).height(36.dp)
-                    )
-
-                    Column(
-                        modifier = Modifier.weight(1.6f),
-                        horizontalAlignment = Alignment.CenterHorizontally
-                    ) {
-                        Text("Hex", color = Color.Gray, fontSize = 12.sp, maxLines = 1)
-                        Spacer(Modifier.height(4.dp))
-                        HexInput(color = currentColor, onHexChanged = { updateFromColor(it) })
-                    }
-
-                    Row(
-                        modifier = Modifier.weight(2.4f),
-                        horizontalArrangement = Arrangement.spacedBy(6.dp)
-                    ) {
-                        RgbInputColumn(
-                            label = "R", value = currentColor.red,
-                            onValueChange = { r -> updateFromColor(currentColor.copy(red = r)) },
-                            modifier = Modifier.weight(1f)
-                        )
-                        RgbInputColumn(
-                            label = "G", value = currentColor.green,
-                            onValueChange = { g -> updateFromColor(currentColor.copy(green = g)) },
-                            modifier = Modifier.weight(1f)
-                        )
-                        RgbInputColumn(
-                            label = "B", value = currentColor.blue,
-                            onValueChange = { b -> updateFromColor(currentColor.copy(blue = b)) },
-                            modifier = Modifier.weight(1f)
-                        )
-                    }
-                }
-
-                Spacer(Modifier.height(24.dp))
-
-                Row(
-                    modifier = Modifier.fillMaxWidth(),
-                    horizontalArrangement = Arrangement.End,
-                    verticalAlignment = Alignment.CenterVertically
-                ) {
-                    Button(
-                        onClick = onDismiss,
-                        colors = androidx.compose.material3.ButtonDefaults.buttonColors(
-                            containerColor = Color.White,
-                            contentColor = Color.Black
-                        )
-                    ) {
-                        Text("Done")
-                    }
-                }
-            }
-        }
-    }
-}
-
-@Composable
-fun TextureOption(name: String, resId: Int?, isSelected: Boolean, onClick: () -> Unit) {
-    Column(horizontalAlignment = Alignment.CenterHorizontally, modifier = Modifier.clickable(onClick = onClick)) {
-        Box(modifier = Modifier.size(48.dp).clip(CircleShape).border(if (isSelected) 3.dp else 1.dp, if (isSelected) MaterialTheme.colorScheme.primary else MaterialTheme.colorScheme.outlineVariant, CircleShape).run {
-            if (resId != null) {
-                val bmp = ImageBitmap.imageResource(LocalResources.current, resId)
-                this.drawBehind { drawRect(ShaderBrush(ImageShader(bmp, TileMode.Repeated, TileMode.Repeated))) }
-            } else this.background(MaterialTheme.colorScheme.surfaceVariant)
-        })
-        Text(name, style = MaterialTheme.typography.labelSmall, modifier = Modifier.padding(top = 4.dp))
-    }
-}
-
-@Composable
-fun ColorSlider(color: Color, onColorChanged: (Color) -> Unit) {
-    Row(verticalAlignment = Alignment.CenterVertically, horizontalArrangement = Arrangement.spacedBy(8.dp)) {
-        Slider(value = color.red, onValueChange = { onColorChanged(color.copy(red = it)) }, colors = androidx.compose.material3.SliderDefaults.colors(thumbColor = Color.Red, activeTrackColor = Color.Red), modifier = Modifier.weight(1f))
-        Slider(value = color.green, onValueChange = { onColorChanged(color.copy(green = it)) }, colors = androidx.compose.material3.SliderDefaults.colors(thumbColor = Color.Green, activeTrackColor = Color.Green), modifier = Modifier.weight(1f))
-        Slider(value = color.blue, onValueChange = { onColorChanged(color.copy(blue = it)) }, colors = androidx.compose.material3.SliderDefaults.colors(thumbColor = Color.Blue, activeTrackColor = Color.Blue), modifier = Modifier.weight(1f))
-    }
 }

app/src/main/java/com/aryan/reader/paginatedreader/PaginatedReader.kt

@@ -158,6 +158,7 @@ import coil.compose.AsyncImage
 import coil.imageLoader
 import coil.request.ImageRequest.Builder
 import com.aryan.reader.R
+import com.aryan.reader.ReaderTexture
 import com.aryan.reader.countWords
 import com.aryan.reader.epub.EpubBook
 import com.aryan.reader.epubreader.HighlightColor
@@ -529,7 +530,7 @@ fun PaginatedReaderScreen(
     val context = LocalContext.current
     val textureBitmap = remember(activeTextureId) {
         activeTextureId?.let { id ->
-            com.aryan.reader.epubreader.ReaderTexture.entries.find { it.id == id }?.resId?.let { resId ->
+            ReaderTexture.entries.find { it.id == id }?.resId?.let { resId ->
                 androidx.compose.ui.graphics.ImageBitmap.imageResource(context.resources, resId)
             }
         }

app/src/main/java/com/aryan/reader/pdf/PdfPageComposable.kt

@@ -407,7 +407,7 @@ internal fun PdfPageComposable(
     clearSelectionTrigger: Long = 0L,
     onTtsHighlightCenterCalculated: ((Float) -> Unit)? = null,
     onSearchHighlightCenterCalculated: ((Float) -> Unit)? = null,
-    isDarkMode: Boolean = false,
+    activeTheme: com.aryan.reader.ReaderTheme = com.aryan.reader.ReaderTheme("no_theme", "No Theme", Color.Unspecified, Color.Unspecified, false),
     onDoubleTap: ((Offset) -> Unit)? = null,
     isEditMode: Boolean = false,
     drawingState: PdfDrawingState? = null,
@@ -534,41 +534,55 @@ internal fun PdfPageComposable(
     val canvasWidthPx = remember { mutableFloatStateOf(0f) }
     val canvasHeightPx = remember { mutableFloatStateOf(0f) }
 
-    val colorFilter = remember(isDarkMode) {
+    val isDarkMode = activeTheme.isDark || activeTheme.id == "reverse"
-        if (isDarkMode) {
+
-            val colorMatrix = floatArrayOf(
+    val colorFilter = remember(activeTheme) {
-                -1f,
+        when (activeTheme.id) {
-                0f,
+            "no_theme", "system" -> null
-                0f,
+            "reverse" -> {
-                0f,
+                val colorMatrix = floatArrayOf(
-                255f,
+                    -1f,  0f,  0f,  0f, 255f,
-                0f,
+                    0f, -1f,  0f,  0f, 255f,
-                -1f,
+                    0f,  0f, -1f,  0f, 255f,
-                0f,
+                    0f,  0f,  0f,  1f,   0f
-                0f,
+                )
-                255f,
+                ColorFilter.colorMatrix(ColorMatrix(colorMatrix))
-                0f,
+            }
-                0f,
+            else -> {
-                -1f,
+                val bgR = activeTheme.backgroundColor.red * 255f
-                0f,
+                val bgG = activeTheme.backgroundColor.green * 255f
-                255f,
+                val bgB = activeTheme.backgroundColor.blue * 255f
-                0f,
+
-                0f,
+                val fgR = activeTheme.textColor.red * 255f
-                0f,
+                val fgG = activeTheme.textColor.green * 255f
-                1f,
+                val fgB = activeTheme.textColor.blue * 255f
-                0f
+
-            )
+                val dr = (bgR - fgR) / 255f
-            ColorFilter.colorMatrix(ColorMatrix(colorMatrix))
+                val dg = (bgG - fgG) / 255f
-        } else {
+                val db = (bgB - fgB) / 255f
-            null
+
+                val lumR = 0.2126f
+                val lumG = 0.7152f
+                val lumB = 0.0722f
+
+                val colorMatrix = floatArrayOf(
+                    dr * lumR, dr * lumG, dr * lumB, 0f, fgR,
+                    dg * lumR, dg * lumG, dg * lumB, 0f, fgG,
+                    db * lumR, db * lumG, db * lumB, 0f, fgB,
+                    0f, 0f, 0f, 1f, 0f
+                )
+                ColorFilter.colorMatrix(ColorMatrix(colorMatrix))
+            }
         }
     }
 
-    val backgroundColor = remember(isDarkMode, isVerticalScroll) {
+    val backgroundColor = remember(activeTheme, isVerticalScroll) {
-        if (isDarkMode) {
+        if (activeTheme.id == "no_theme" || activeTheme.id == "system") {
-            Color(0xFF2A2A2A)
-        } else {
             if (isVerticalScroll) Color.White else Color.Black
+        } else if (activeTheme.id == "reverse") {
+            if (isVerticalScroll) Color.Black else Color.White
+        } else {
+            activeTheme.backgroundColor
         }
     }
 
@@ -1628,10 +1642,6 @@ internal fun PdfPageComposable(
                         }
                     }
 
-                    if (selectedTool == InkType.ERASER) {
-                        eraserPosition = down.position
-                    }
-
                     if (dragStartedOnHandle) {
                         Timber.d(
                             "PointerInput: Drag started on handle $activeDraggingHandle"
@@ -3091,8 +3101,12 @@ internal fun PdfPageComposable(
         }
 
         LaunchedEffect(
-            this@BoxWithConstraints.maxWidth, this@BoxWithConstraints.maxHeight, pageIndex
+            this@BoxWithConstraints.maxWidth, this@BoxWithConstraints.maxHeight
         ) {
+            scale = 1f
+            offset = Offset.Zero
+            onScaleChanged(1f)
+
             Timber.d(
                 "PdfPageComposable Page $pageIndex | Constraints: maxWidth=${this@BoxWithConstraints.maxWidth}, maxHeight=${this@BoxWithConstraints.maxHeight}"
             )
@@ -3861,7 +3875,6 @@ private fun PdfBitmapLayer(
         .fillMaxSize()
         .graphicsLayer()) {
         translate(left = centeringOffsetX, top = centeringOffsetY) {
-            // THIS is the fix: Hard clip to the target bounds so edge tiles can't bleed out.
             clipRect(left = 0f, top = 0f, right = targetWidth.toFloat(), bottom = targetHeight.toFloat()) {
                 if (bitmapState != null && !bitmapState.isRecycled) {
                     val dstW = if (targetWidth > 0) targetWidth else bitmapState.width
@@ -3869,17 +3882,16 @@ private fun PdfBitmapLayer(
                     val srcSize = IntSize(bitmapState.width, bitmapState.height)
                     val dstSize = IntSize(dstW, dstH)
 
-                    // 1. Draw Base Bitmap
                     drawImage(
                         image = bitmapState.asImageBitmap(),
                         srcOffset = IntOffset.Zero,
                         srcSize = srcSize,
                         dstOffset = IntOffset.Zero,
                         dstSize = dstSize,
-                        colorFilter = colorFilter
+                        colorFilter = colorFilter,
+                        filterQuality = androidx.compose.ui.graphics.FilterQuality.High
                     )
 
-                    // 2. Draw High-Res Tiles
                     if (effectiveScale > 1f) {
                         tiles.forEach { tile ->
                             if (!tile.bitmap.isRecycled) {
@@ -3891,7 +3903,8 @@ private fun PdfBitmapLayer(
                                     dstSize = IntSize(
                                         tile.renderRect.width(), tile.renderRect.height()
                                     ),
-                                    colorFilter = colorFilter
+                                    colorFilter = colorFilter,
+                                    filterQuality = androidx.compose.ui.graphics.FilterQuality.High
                                 )
                             }
                         }

app/src/main/java/com/aryan/reader/pdf/PdfVerticalReader.kt

@@ -111,7 +111,6 @@ import com.aryan.reader.SearchResult
 import com.aryan.reader.pdf.data.PdfAnnotation
 import com.aryan.reader.pdf.data.PdfTextBox
 import com.aryan.reader.pdf.data.VirtualPage
-import io.legere.pdfiumandroid.suspend.PdfDocumentKt
 import kotlinx.coroutines.FlowPreview
 import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.delay
@@ -177,7 +176,7 @@ private data class DividerLayout(val y: Float, val width: Float, val height: Flo
 internal fun PdfVerticalReader(
     state: VerticalPdfReaderState,
     pdfDocument: StableHolder<ReaderDocument>,
-    isDarkMode: Boolean,
+    activeTheme: com.aryan.reader.ReaderTheme,
     totalPages: Int,
     modifier: Modifier = Modifier,
     virtualPages: List<VirtualPage> = emptyList(),
@@ -243,6 +242,7 @@ internal fun PdfVerticalReader(
         }
     }
     var globalEraserPosition by remember { mutableStateOf<Offset?>(null) }
+    val isDarkMode = activeTheme.isDark || activeTheme.id == "reverse"
     BoxWithConstraints(modifier = modifier.fillMaxSize(), contentAlignment = Alignment.TopStart) {
         val imeInsets = WindowInsets.ime
         val density = LocalDensity.current
@@ -1497,7 +1497,7 @@ internal fun PdfVerticalReader(
                                     pageIndex = page.index,
                                     virtualPage = virtualPage,
                                     totalPages = totalPages,
-                                    isDarkMode = isDarkMode,
+                                    activeTheme = activeTheme,
                                     externalScale = highResScale,
                                     onScaleChanged = {},
                                     showAllTextHighlights = showAllTextHighlights,

app/src/main/java/com/aryan/reader/pdf/PdfViewerScreen.kt

@@ -259,6 +259,7 @@ import com.aryan.reader.DeviceVoiceSettingsSheet
 import com.aryan.reader.FileType
 import com.aryan.reader.MainViewModel
 import com.aryan.reader.R
+import com.aryan.reader.ReaderThemePanel
 import com.aryan.reader.SearchResult
 import com.aryan.reader.SearchTopBar
 import com.aryan.reader.SummarizationPopup
@@ -270,6 +271,7 @@ import com.aryan.reader.epubreader.AutoScrollControls
 import com.aryan.reader.epubreader.DictionarySettingsDialog
 import com.aryan.reader.epubreader.ExternalDictionaryHelper
 import com.aryan.reader.fetchAiDefinition
+import com.aryan.reader.loadCustomThemes
 import com.aryan.reader.paginatedreader.TtsChunk
 import com.aryan.reader.pdf.data.AnnotationSettingsRepository
 import com.aryan.reader.pdf.data.PdfAnnotation
@@ -281,6 +283,7 @@ import com.aryan.reader.pdf.data.SmartSearchResult
 import com.aryan.reader.pdf.data.TextStyleConfig
 import com.aryan.reader.pdf.data.VirtualPage
 import com.aryan.reader.rememberSearchState
+import com.aryan.reader.saveCustomThemes
 import com.aryan.reader.summarizationUrl
 import com.aryan.reader.tts.SpeakerSamplePlayer
 import com.aryan.reader.tts.TtsPlaybackManager
@@ -343,6 +346,27 @@ private const val PREF_USE_ONLINE_DICT = "use_online_dictionary"
 private const val PREF_EXTERNAL_DICT_PKG = "external_dictionary_package"
 private const val PREF_EXTERNAL_TRANSLATE_PKG = "external_translate_package"
 private const val PREF_EXTERNAL_SEARCH_PKG = "external_search_package"
+private const val PDF_THEME_KEY = "pdf_reader_theme"
+
+private fun savePdfThemeId(context: Context, themeId: String) {
+    val prefs = context.getSharedPreferences(SETTINGS_PREFS_NAME, Context.MODE_PRIVATE)
+    prefs.edit { putString(PDF_THEME_KEY, themeId) }
+}
+
+private fun loadPdfThemeId(context: Context): String {
+    val prefs = context.getSharedPreferences(SETTINGS_PREFS_NAME, Context.MODE_PRIVATE)
+    return prefs.getString(PDF_THEME_KEY, "no_theme") ?: "no_theme"
+}
+
+val PdfBuiltInThemes = listOf(
+    com.aryan.reader.ReaderTheme("no_theme", "No Theme", Color.Unspecified, Color.Unspecified, false),
+    com.aryan.reader.ReaderTheme("reverse", "Reverse", Color.Black, Color.White, true),
+    com.aryan.reader.ReaderTheme("light", "Light", Color(0xFFFFFFFF), Color(0xFF000000), false),
+    com.aryan.reader.ReaderTheme("dark", "Dark", Color(0xFF121212), Color(0xFFE0E0E0), true),
+    com.aryan.reader.ReaderTheme("sepia", "Sepia", Color(0xFFFBF0D9), Color(0xFF5F4B32), false),
+    com.aryan.reader.ReaderTheme("slate", "Slate", Color(0xFF2E3440), Color(0xFFECEFF4), true),
+    com.aryan.reader.ReaderTheme("oled", "OLED", Color(0xFF000000), Color(0xFFB0B0B0), true)
+)
 
 object PdfiumCoreProvider {
     val core: PdfiumCoreKt by lazy {
@@ -1065,7 +1089,16 @@ fun PdfViewerScreen(
     val focusManager = LocalFocusManager.current
     val drawerState = rememberDrawerState(initialValue = DrawerValue.Closed)
     var displayMode by remember { mutableStateOf(loadDisplayMode(context)) }
-    var isPdfDarkMode by remember { mutableStateOf(loadPdfDarkMode(context)) }
+    var showThemePanel by remember { mutableStateOf(false) }
+    var currentThemeId by remember { mutableStateOf(loadPdfThemeId(context)) }
+    var customThemes by remember { mutableStateOf(loadCustomThemes(context)) }
+
+    val activeTheme = remember(currentThemeId, customThemes) {
+        PdfBuiltInThemes.find { it.id == currentThemeId }
+            ?: customThemes.find { it.id == currentThemeId }
+            ?: PdfBuiltInThemes[0]
+    }
+    val isPdfDarkMode = activeTheme.isDark || activeTheme.id == "reverse"
     var pageAspectRatios by remember { mutableStateOf<List<Float>>(emptyList()) }
     var showBars by rememberSaveable { mutableStateOf(true) }
     var isFullScreen by remember { mutableStateOf(false) }
@@ -1364,7 +1397,6 @@ fun PdfViewerScreen(
     LaunchedEffect(ocrLanguage) { OcrHelper.init(ocrLanguage) }
 
     LaunchedEffect(displayMode) { saveDisplayMode(context, displayMode) }
-    LaunchedEffect(isPdfDarkMode) { savePdfDarkMode(context, isPdfDarkMode) }
 
     val annotationSettingsRepo = remember(context) { AnnotationSettingsRepository(context) }
     val toolSettings by annotationSettingsRepo.settings.collectAsState()
@@ -2724,21 +2756,24 @@ fun PdfViewerScreen(
     ): Boolean {
         if (annotation.points.isEmpty()) return false
 
+        val effectiveThreshold = threshold + (annotation.strokeWidth / 2f)
+        val thresholdSq = effectiveThreshold * effectiveThreshold
+
         if (annotation.points.size == 1) {
             val p = annotation.points[0]
-            val dx = (p.x - hitPoint.x) * pageAspectRatio
+            val dx = (p.x - hitPoint.x)
-            val dy = (p.y - hitPoint.y)
+            val dy = (p.y - hitPoint.y) / pageAspectRatio
-            return (dx * dx + dy * dy) < (threshold * threshold)
+            return (dx * dx + dy * dy) < thresholdSq
         }
 
         for (i in 0 until annotation.points.size - 1) {
             val a = annotation.points[i]
             val b = annotation.points[i + 1]
 
-            val pax = (hitPoint.x - a.x) * pageAspectRatio
+            val pax = (hitPoint.x - a.x)
-            val pay = (hitPoint.y - a.y)
+            val pay = (hitPoint.y - a.y) / pageAspectRatio
-            val bax = (b.x - a.x) * pageAspectRatio
+            val bax = (b.x - a.x)
-            val bay = (b.y - a.y)
+            val bay = (b.y - a.y) / pageAspectRatio
 
             val segmentLenSq = (bax * bax + bay * bay).coerceAtLeast(1e-6f)
             val t = (pax * bax + pay * bay) / segmentLenSq
@@ -2749,7 +2784,7 @@ fun PdfViewerScreen(
 
             val distSq = (pax - closestX) * (pax - closestX) + (pay - closestY) * (pay - closestY)
 
-            if (distSq < (threshold * threshold)) return true
+            if (distSq < thresholdSq) return true
         }
 
         return false
@@ -3580,6 +3615,7 @@ fun PdfViewerScreen(
             }
 
             showTtsSettingsSheet -> showTtsSettingsSheet = false
+            showThemePanel -> showThemePanel = false
 
             else -> {
                 saveStateAndExit()
@@ -4257,7 +4293,7 @@ fun PdfViewerScreen(
                                                 pageIndex = pageIndex,
                                                 virtualPage = virtualPage,
                                                 totalPages = totalDisplayPages,
-                                                isDarkMode = isPdfDarkMode,
+                                                activeTheme = activeTheme,
                                                 isScrollLocked = isScrollLocked,
                                                 onScaleChanged = { newScale ->
                                                     if (pagerState.currentPage == pageIndex) {
@@ -4636,7 +4672,7 @@ fun PdfViewerScreen(
                                         PdfVerticalReader(
                                             state = verticalReaderState,
                                             pdfDocument = docHolder,
-                                            isDarkMode = isPdfDarkMode,
+                                            activeTheme = activeTheme,
                                             isScrollLocked = isScrollLocked,
                                             totalPages = totalDisplayPages,
                                             pageAspectRatios = ratiosHolder,
@@ -5223,22 +5259,14 @@ fun PdfViewerScreen(
                                 )
 
                                 TooltipIconButton(
-                                    text = if (isPdfDarkMode)
+                                    text = "Theme",
-                                        stringResource(R.string.tooltip_dark_mode_off)
+                                    description = "Theme Settings",
-                                    else
+                                    onClick = { showThemePanel = true }
-                                        stringResource(R.string.tooltip_dark_mode_on),
-                                    description = if (isPdfDarkMode)
-                                        stringResource(R.string.tooltip_dark_mode_off_desc)
-                                    else
-                                        stringResource(R.string.tooltip_dark_mode_on_desc),
-                                    onClick = { isPdfDarkMode = !isPdfDarkMode }
                                 ) {
                                     Icon(
-                                        painter = painterResource(id = R.drawable.dark_mode),
+                                        painter = painterResource(id = R.drawable.palette),
-                                        contentDescription = if (isPdfDarkMode) "Disable Dark Mode"
+                                        contentDescription = "Theme Settings",
-                                        else "Enable Dark Mode",
+                                        tint = MaterialTheme.colorScheme.onSurfaceVariant
-                                        tint = if (isPdfDarkMode) MaterialTheme.colorScheme.primary
-                                        else MaterialTheme.colorScheme.onSurfaceVariant
                                     )
                                 }
 
@@ -6926,6 +6954,25 @@ fun PdfViewerScreen(
                     )
                 }
 
+                if (showThemePanel) {
+                    ReaderThemePanel(
+                        isVisible = true,
+                        currentThemeId = currentThemeId,
+                        builtInThemes = PdfBuiltInThemes,
+                        onThemeSelected = {
+                            currentThemeId = it
+                            savePdfThemeId(context, it)
+                            showThemePanel = false
+                        },
+                        onDismiss = { showThemePanel = false },
+                        customThemes = customThemes,
+                        onCustomThemesUpdated = {
+                            customThemes = it
+                            saveCustomThemes(context, it)
+                        }
+                    )
+                }
+
                 if (clickedLinkUrl != null) {
                     val url = clickedLinkUrl!!
                     AlertDialog(

app/src/main/java/com/aryan/reader/pdf/ToolSettingsPopup.kt

@@ -128,7 +128,7 @@ fun ToolSettingsPopup(
 
     val thicknessRange = when {
         isHighlighter -> 0.01f..0.06f
-        isEraser -> 0.01f..0.1f
+        isEraser -> 0.002f..0.1f
         else -> 0.001f..0.015f
     }
     @Suppress("UnusedExpression") if (isHighlighter) 0.005f else 0.001f
@@ -170,9 +170,9 @@ fun ToolSettingsPopup(
                         .height(125.dp),
                     contentAlignment = Alignment.Center
                 ) {
-                    val radiusDp = (activeToolThickness * 1000).coerceIn(10f, 100f).dp
+                    val diameterDp = (activeToolThickness * 800).coerceIn(4f, 150f).dp
                     Box(
-                        modifier = Modifier.size(radiusDp),
+                        modifier = Modifier.size(diameterDp),
                         contentAlignment = Alignment.Center
                     ) {
                         Canvas(modifier = Modifier.fillMaxSize()) {

app/src/main/java/com/aryan/reader/pdf/UniversalDocument.kt

@@ -219,8 +219,7 @@ class ArchiveDocumentWrapper(private val file: File) : ReaderDocument {
                         tempEntries.add(Pair(path, extractedFile))
 
                         var pfd: android.os.ParcelFileDescriptor? = null
-                        try {
+                        @Suppress("ConvertTryFinallyToUseCall") try {
-                            // Extract seamlessly using fd to avoid ByteBuffer's state sync bug
                             pfd = android.os.ParcelFileDescriptor.open(extractedFile, android.os.ParcelFileDescriptor.MODE_READ_WRITE or android.os.ParcelFileDescriptor.MODE_CREATE)
                             Archive.readDataIntoFd(archive, pfd.fd)
                         } finally {
@@ -231,7 +230,7 @@ class ArchiveDocumentWrapper(private val file: File) : ReaderDocument {
                     }
                 }
 
-                tempEntries.sortBy { it.first } // Natural sorting order based on the filename inside the archive
+                tempEntries.sortBy { it.first }
                 tempEntries.forEach { imageEntries.add(it.second.absolutePath) }
 
             } catch (e: Exception) {
@@ -306,15 +305,42 @@ class ArchivePageWrapper(imageBytes: ByteArray) : ReaderPage {
         val scaleX = drawSizeX.toFloat() / originalWidth
         val scaleY = drawSizeY.toFloat() / originalHeight
 
-        val srcLeft = (-startX / scaleX).toInt().coerceAtLeast(0)
+        val pageOffsetX = -startX.toFloat()
-        val srcTop = (-startY / scaleY).toInt().coerceAtLeast(0)
+        val pageOffsetY = -startY.toFloat()
-        val srcRight = (srcLeft + (bitmap.width / scaleX).toInt()).coerceAtMost(originalWidth)
+
-        val srcBottom = (srcTop + (bitmap.height / scaleY).toInt()).coerceAtMost(originalHeight)
+        val exactSrcLeft = pageOffsetX / scaleX
+        val exactSrcTop = pageOffsetY / scaleY
+        val exactSrcRight = (pageOffsetX + bitmap.width) / scaleX
+        val exactSrcBottom = (pageOffsetY + bitmap.height) / scaleY
+
+        val srcLeft = kotlin.math.floor(exactSrcLeft).toInt().coerceAtLeast(0)
+        val srcTop = kotlin.math.floor(exactSrcTop).toInt().coerceAtLeast(0)
+        val srcRight = kotlin.math.ceil(exactSrcRight).toInt().coerceAtMost(originalWidth)
+        val srcBottom = kotlin.math.ceil(exactSrcBottom).toInt().coerceAtMost(originalHeight)
 
         val rect = Rect(srcLeft, srcTop, srcRight, srcBottom)
         if (rect.width() <= 0 || rect.height() <= 0) return
 
-        val options = BitmapFactory.Options().apply { inPreferredConfig = Bitmap.Config.ARGB_8888 }
+        val options = BitmapFactory.Options().apply {
+            inPreferredConfig = Bitmap.Config.ARGB_8888
+            inScaled = false
+            @Suppress("DEPRECATION")
+            inDither = true
+
+            var sampleSize = 1
+            val srcWidth = rect.width()
+            val srcHeight = rect.height()
+
+            if (srcHeight > bitmap.height || srcWidth > bitmap.width) {
+                val halfHeight = srcHeight / 2
+                val halfWidth = srcWidth / 2
+                while (halfHeight / sampleSize >= bitmap.height && halfWidth / sampleSize >= bitmap.width) {
+                    sampleSize *= 2
+                }
+            }
+            inSampleSize = sampleSize
+        }
+
         val region = try {
             decoder.decodeRegion(rect, options)
         } catch (_: Exception) {
@@ -323,8 +349,17 @@ class ArchivePageWrapper(imageBytes: ByteArray) : ReaderPage {
 
         if (region != null) {
             val canvas = Canvas(bitmap)
-            val destRect = Rect(0, 0, bitmap.width, bitmap.height)
+
-            canvas.drawBitmap(region, null, destRect, Paint(Paint.FILTER_BITMAP_FLAG))
+            val destLeft = (srcLeft * scaleX) - pageOffsetX
+            val destTop = (srcTop * scaleY) - pageOffsetY
+            val destRight = (srcRight * scaleX) - pageOffsetX
+            val destBottom = (srcBottom * scaleY) - pageOffsetY
+
+            val destRect = RectF(destLeft, destTop, destRight, destBottom)
+
+            val paint = Paint(Paint.FILTER_BITMAP_FLAG or Paint.ANTI_ALIAS_FLAG or Paint.DITHER_FLAG)
+
+            canvas.drawBitmap(region, null, destRect, paint)
             region.recycle()
         }
     }