diff --git a/.idea/deploymentTargetSelector.xml b/.idea/deploymentTargetSelector.xml
index 31a4bd1..768e340 100644
--- a/.idea/deploymentTargetSelector.xml
+++ b/.idea/deploymentTargetSelector.xml
@@ -4,10 +4,10 @@
     <selectionStates>
       <SelectionState runConfigName="app">
         <option name="selectionMode" value="DROPDOWN" />
-        <DropdownSelection timestamp="2024-07-19T09:50:49.472753800Z">
+        <DropdownSelection timestamp="2024-09-12T07:23:44.202200Z">
           <Target type="DEFAULT_BOOT">
             <handle>
-              <DeviceId pluginId="PhysicalDevice" identifier="serial=ZD2228B6BX" />
+              <DeviceId pluginId="PhysicalDevice" identifier="serial=9SYPJV65WOAYJZAM" />
             </handle>
           </Target>
         </DropdownSelection>
diff --git a/app/build.gradle.kts b/app/build.gradle.kts
index 9faf290..a121508 100644
--- a/app/build.gradle.kts
+++ b/app/build.gradle.kts
@@ -14,8 +14,8 @@ android {
         applicationId = "com.googol.android.apps.photos"
         minSdk = 24
         targetSdk = 35
-        versionCode = 13
-        versionName = "0.1.0-dev13"
+        versionCode = 14
+        versionName = "0.1.0-dev14"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
         vectorDrawables {
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
index 4581a69..1eff747 100644
--- a/app/src/main/AndroidManifest.xml
+++ b/app/src/main/AndroidManifest.xml
@@ -2,6 +2,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools">
 
+    <!--Required to provide app-lock feature.-->
+    <uses-permission android:name="android.permission.USE_BIOMETRIC" />
     <!-- Devices running Android 12L (API level 32) or lower  -->
     <uses-permission
         android:name="android.permission.WRITE_EXTERNAL_STORAGE"
@@ -11,6 +13,9 @@
     <uses-permission android:name="android.permission.READ_MEDIA_IMAGES" />
     <uses-permission android:name="android.permission.READ_MEDIA_VIDEO" />
 
+    <!-- Required to access GPS Data of Media -->
+    <uses-permission android:name="android.permission.ACCESS_MEDIA_LOCATION" />
+
     <!-- To handle the reselection within the app on devices running Android 14
          or higher if your app targets Android 14 (API level 34) or higher.  -->
     <uses-permission android:name="android.permission.READ_MEDIA_VISUAL_USER_SELECTED" />
diff --git a/app/src/main/java/com/zs/gallery/Home.kt b/app/src/main/java/com/zs/gallery/Gallery.kt
similarity index 64%
rename from app/src/main/java/com/zs/gallery/Home.kt
rename to app/src/main/java/com/zs/gallery/Gallery.kt
index ce00028..2e693f6 100644
--- a/app/src/main/java/com/zs/gallery/Home.kt
+++ b/app/src/main/java/com/zs/gallery/Gallery.kt
@@ -1,7 +1,7 @@
 /*
  * Copyright 2024 Zakir Sheikh
  *
- * Created by Zakir Sheikh on 23-07-2024.
+ * Created by 2024 on 11-09-2024.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,29 +19,22 @@
 package com.zs.gallery
 
 import android.os.Build
-import androidx.compose.animation.core.tween
-import androidx.compose.animation.fadeIn
-import androidx.compose.animation.fadeOut
-import androidx.compose.animation.scaleIn
-import androidx.compose.foundation.background
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.foundation.layout.PaddingValues
 import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.WindowInsets
-import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.foundation.layout.heightIn
 import androidx.compose.foundation.layout.navigationBars
 import androidx.compose.foundation.layout.size
 import androidx.compose.foundation.layout.statusBars
-import androidx.compose.foundation.layout.systemBars
-import androidx.compose.foundation.layout.width
+import androidx.compose.foundation.layout.widthIn
 import androidx.compose.foundation.shape.CircleShape
-import androidx.compose.foundation.shape.GenericShape
-import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.BottomAppBar
 import androidx.compose.material.BottomNavigation
 import androidx.compose.material.ButtonDefaults
 import androidx.compose.material.ExperimentalMaterialApi
 import androidx.compose.material.Icon
+import androidx.compose.material.LocalElevationOverlay
 import androidx.compose.material.NavigationRail
 import androidx.compose.material.SelectableChipColors
 import androidx.compose.material.icons.Icons
@@ -56,22 +49,18 @@ import androidx.compose.runtime.movableContentOf
 import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
-import androidx.compose.ui.geometry.Size
 import androidx.compose.ui.graphics.Color
-import androidx.compose.ui.graphics.Outline
-import androidx.compose.ui.graphics.Path
-import androidx.compose.ui.graphics.Shape
-import androidx.compose.ui.platform.LocalContext
+import androidx.compose.ui.platform.LocalDensity
+import androidx.compose.ui.platform.LocalView
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.unit.Density
-import androidx.compose.ui.unit.LayoutDirection
 import androidx.compose.ui.unit.dp
 import androidx.navigation.NavController
 import androidx.navigation.NavGraph.Companion.findStartDestination
 import androidx.navigation.NavGraphBuilder
+import androidx.navigation.NavHostController
 import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.currentBackStackEntryAsState
-import androidx.navigation.compose.rememberNavController
 import com.google.accompanist.permissions.ExperimentalPermissionsApi
 import com.google.accompanist.permissions.rememberMultiplePermissionsState
 import com.primex.core.plus
@@ -82,14 +71,15 @@ import com.zs.foundation.AppTheme
 import com.zs.foundation.LocalWindowSize
 import com.zs.foundation.Range
 import com.zs.foundation.WindowSize
-import com.zs.foundation.isPermissionGranted
 import com.zs.foundation.adaptive.BottomNavItem
 import com.zs.foundation.adaptive.NavRailItem
 import com.zs.foundation.adaptive.NavigationItemDefaults
 import com.zs.foundation.adaptive.NavigationSuiteScaffold
+import com.zs.foundation.calculateWindowSizeClass
+import com.zs.foundation.checkSelfPermissions
 import com.zs.foundation.renderInSharedTransitionScopeOverlay
+import com.zs.foundation.shapes.EndConcaveShape
 import com.zs.foundation.shapes.TopConcaveShape
-import com.zs.foundation.thenIf
 import com.zs.foundation.toast.ToastHostState
 import com.zs.gallery.bin.RouteTrash
 import com.zs.gallery.bin.Trash
@@ -97,10 +87,10 @@ import com.zs.gallery.common.LocalNavController
 import com.zs.gallery.common.LocalSystemFacade
 import com.zs.gallery.common.NightMode
 import com.zs.gallery.common.Route
+import com.zs.gallery.common.SystemFacade
 import com.zs.gallery.common.composable
 import com.zs.gallery.common.current
 import com.zs.gallery.common.domain
-import com.zs.gallery.common.preference
 import com.zs.gallery.files.Album
 import com.zs.gallery.files.Folder
 import com.zs.gallery.files.RouteAlbum
@@ -116,54 +106,110 @@ import com.zs.gallery.impl.SettingsViewModel
 import com.zs.gallery.impl.TimelineViewModel
 import com.zs.gallery.impl.TrashViewModel
 import com.zs.gallery.impl.ViewerViewModel
-import com.zs.gallery.viewer.RouteViewer
-import com.zs.gallery.viewer.Viewer
+import com.zs.gallery.lockscreen.LockScreen
+import com.zs.gallery.lockscreen.RouteLockScreen
 import com.zs.gallery.settings.RouteSettings
 import com.zs.gallery.settings.Settings
+import com.zs.gallery.viewer.RouteViewer
+import com.zs.gallery.viewer.Viewer
 import org.koin.androidx.compose.koinViewModel
 
-private const val TAG = "Home"
+private const val TAG = "Gallery"
+
+private val NAV_RAIL_MIN_WIDTH = 106.dp
+private val BOTTOM_NAV_MIN_HEIGHT = 56.dp
 
 /**
- * Observes whether the app is in light mode based on the user's preference and system settings.
+ * Adjusts the [WindowSize] by consuming either the navigation rail width or the bottom navigation height.
  *
- * @return `true` if the app is in light mode, `false` otherwise.
+ * @param rail Boolean indicating whether to consume the navigation rail width.
+ * @return [WindowSize] with the specified dimension consumed.
  */
-@Composable
-@NonRestartableComposable
-private fun isPreferenceDarkTheme(): Boolean {
-    val mode by preference(key = Settings.KEY_NIGHT_MODE)
-    return when (mode) {
-        NightMode.YES -> true
-        NightMode.NO -> false
-        NightMode.FOLLOW_SYSTEM -> isSystemInDarkTheme()
+private fun WindowSize.consume(rail: Boolean) =
+    if (rail) consume(width = NAV_RAIL_MIN_WIDTH) else consume(height = BOTTOM_NAV_MIN_HEIGHT)
+
+/**
+ * @return if preferred orientation of layout is portrait
+ */
+private inline val WindowSize.portrait
+    get() = widthRange < Range.Medium
+
+/**
+ *Navigates to the specified route, managing the back stack for a seamless experience.
+ * Pops up to the start destination and uses launchSingleTop to prevent duplicate destinations.
+ *
+ * @param route The destination route.
+ */
+private fun NavController.toRoute(route: Route) {
+    navigate(route()) {
+        // Pop up to the start destination of the graph to
+        // avoid building up a large stack of destinations
+        // on the back stack as users select items
+        popUpTo(graph.findStartDestination().id) {
+            saveState = true
+        }
+        // Avoid multiple copies of the same destination when
+        // re-selecting the same item
+        launchSingleTop = true
+        // Restore state when re-selecting a previously selected item
+        restoreState = true
     }
 }
 
 /**
- * The route to permission screen.
+ * The set of domains that require the navigation bar to be shown.
+ * For other domains, the navigation bar will be hidden.
  */
-private object RoutePermission : Route
+private val DOMAINS_REQUIRING_NAV_BAR =
+    arrayOf(RouteTimeline.domain, RouteFolders.domain, RouteSettings.domain)
 
 /**
- * List of required storage permissions, adapted for different Android versions.
+ * Provides a [Density] object that reflects the user's preferred font scale.
+ *
+ * This extension function on [Preferences] observes the `KEY_FONT_SCALE` preference
+ * and returns a modified [Density] object if the user has set a custom font scale.
+ * If the font scale is set to -1 (default), the current [LocalDensity] is returned.
+ *
+ * @return A [Density] object with the appropriate font scale applied.
  */
-private val ADAPTIVE_STORAGE_PERMISSIONS =
-    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE) listOf(
-        android.Manifest.permission.READ_MEDIA_VIDEO,
-        android.Manifest.permission.READ_MEDIA_IMAGES,
-        android.Manifest.permission.READ_MEDIA_VISUAL_USER_SELECTED,
-    )
-    else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) listOf(
-        android.Manifest.permission.READ_MEDIA_VIDEO,
-        android.Manifest.permission.READ_MEDIA_IMAGES
-    )
-    else listOf(android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
+private val SystemFacade.density: Density
+    @NonRestartableComposable
+    @Composable
+    get() {
+        // Observe font scale preference and create a modified Density if necessary
+        val fontScale by observeAsState(key = Settings.KEY_FONT_SCALE)
+        val density = LocalDensity.current
+        return if (fontScale == -1f) density else Density(density.density, fontScale)
+    }
+
+/**
+ * List of permissions required to run the app.
+ *
+ * This list is constructed based on the device's Android version to ensure
+ * compatibility with scoped storage and legacy storage access.
+ */
+private val REQUIRED_PERMISSIONS = buildList {
+    // For Android Tiramisu (33) and above, use media permissions for scoped storage
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+        this += android.Manifest.permission.ACCESS_MEDIA_LOCATION
+        this += android.Manifest.permission.READ_MEDIA_VIDEO
+        this += android.Manifest.permission.READ_MEDIA_IMAGES
+    }
+    // For Android Upside Down Cake (34) and above, add permission for user-selected visual media
+    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.UPSIDE_DOWN_CAKE)
+        this += android.Manifest.permission.READ_MEDIA_VISUAL_USER_SELECTED
+    // For Android versions below Tiramisu 10(29), request WRITE_EXTERNAL_STORAGE for
+    // legacy storage access
+    if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.Q)
+        this += android.Manifest.permission.WRITE_EXTERNAL_STORAGE
+}
+
+private object RoutePermission : Route
 
 /**
  * Represents the permission screen
- * @see ADAPTIVE_STORAGE_PERMISSIONS
- * @see PERMISSION_ROUTE
+ * @see REQUIRED_PERMISSIONS
+ * @see RoutePermission
  */
 @OptIn(ExperimentalPermissionsApi::class)
 @Composable
@@ -172,15 +218,17 @@ private fun Permission() {
     // Compose the permission state.
     // Once granted set different route like folders as start.
     // Navigate from here to there.
-    val permission = rememberMultiplePermissionsState(permissions = ADAPTIVE_STORAGE_PERMISSIONS) {
-        if (!it.all { (_, state) -> state }) return@rememberMultiplePermissionsState
-        controller.graph.setStartDestination(RouteTimeline())
-        controller.navigate(RouteTimeline()) {
-            popUpTo(RoutePermission()) {
-                inclusive = true
+    val permission =
+        rememberMultiplePermissionsState(permissions = REQUIRED_PERMISSIONS) {
+            if (!it.all { (_, state) -> state }) return@rememberMultiplePermissionsState
+            controller.graph.setStartDestination(RouteTimeline())
+            controller.navigate(RouteTimeline()) {
+                popUpTo(RoutePermission()) {
+                    inclusive = true
+                }
             }
         }
-    }
+    // If the permissions are not granted, show the permission screen.
     com.zs.gallery.common.Placeholder(
         iconResId = R.raw.lt_permission,
         title = stringResource(R.string.permission_screen_title),
@@ -200,52 +248,66 @@ private fun Permission() {
 }
 
 /**
- * return the navigation type based on the window size.
+ *  The navigation graph for the app.
  */
-private inline val WindowSize.navTypeRail get() = widthRange > Range.Medium
+private val navGraphBuilder: NavGraphBuilder.() -> Unit = {
+    // Route for handling storage permissions.
+    composable(RoutePermission) { Permission() }
 
-private val NAV_RAIL_WIDTH = 96.dp
+    // Route for the Timeline screen.
+    composable(RouteTimeline) {
+        val state = koinViewModel<TimelineViewModel>()
+        Timeline(viewState = state)
+    }
 
-/**
- * Calculates an returns newWindowSizeClass after consuming sapce occupied by  [navType].
- *
- * @return consumed window class.
- * @see [navType]
- */
-private inline val WindowSize.remaining
-    get() = when {
-        !navTypeRail -> consume(height = 56.dp)
-        else -> consume(width = NAV_RAIL_WIDTH)
+    // Folders
+    composable(RouteFolders) {
+        val state = koinViewModel<FoldersViewModel>()
+        Folders(viewState = state)
     }
 
-/**
- *Navigates to the specified route, managing the back stack for a seamless experience.
- * Pops up to the start destination and uses launchSingleTop to prevent duplicate destinations.
- *
- * @param route The destination route.
- */
-private fun NavController.toRoute(route: String) {
-    navigate(route) {
-        // Pop up to the start destination of the graph to
-        // avoid building up a large stack of destinations
-        // on the back stack as users select items
-        popUpTo(graph.findStartDestination().id) {
-            saveState = true
-        }
-        // Avoid multiple copies of the same destination when
-        // re-selecting the same item
-        launchSingleTop = true
-        // Restore state when re-selecting a previously selected item
-        restoreState = true
+    // Settings
+    composable(RouteSettings) {
+        val state = koinViewModel<SettingsViewModel>()
+        Settings(viewState = state)
+    }
+
+    // Viewer
+    composable(RouteViewer) {
+        val state = koinViewModel<ViewerViewModel>()
+        Viewer(viewState = state)
+    }
+
+    // Folder - That displays files
+    composable(RouteFolder) {
+        val state = koinViewModel<FolderViewModel>()
+        Folder(viewState = state)
+    }
+
+    // Album
+    composable(RouteAlbum) {
+        val state = koinViewModel<AlbumViewModel>()
+        Album(viewState = state)
+    }
+
+    // Trash
+    composable(RouteTrash) {
+        val state = koinViewModel<TrashViewModel>()
+        Trash(viewState = state)
+    }
+
+    // LockScreen
+    composable(RouteLockScreen) {
+        LockScreen()
     }
 }
 
 @OptIn(ExperimentalMaterialApi::class)
 @Composable
-fun NavItem(
-    onClick: () -> Unit,
-    icon: @Composable () -> Unit,
-    label: @Composable (() -> Unit),
+private inline fun NavItem(
+    noinline onClick: () -> Unit,
+    noinline icon: @Composable () -> Unit,
+    noinline label: @Composable (() -> Unit),
     modifier: Modifier = Modifier,
     checked: Boolean = false,
     typeRail: Boolean = false,
@@ -257,8 +319,8 @@ fun NavItem(
     }
 }
 
-
-private val BottomNavShape = RoundedCornerShape(16)
+private val BottomNavShape = TopConcaveShape(radius = 20.dp)
+private val NavRailShape = EndConcaveShape(16.dp)
 
 /**
  * A composable function that represents a navigation bar, combining both rail and bottom bar elements.
@@ -288,7 +350,7 @@ private fun NavigationBar(
                 label = { Label(text = textResource(R.string.photos)) },
                 icon = { Icon(imageVector = Icons.Filled.PhotoLibrary, contentDescription = null) },
                 checked = domain == RouteTimeline.domain,
-                onClick = { facade.launchReviewFlow(); navController.toRoute(RouteTimeline()) },
+                onClick = { facade.launchReviewFlow(); navController.toRoute(RouteTimeline) },
                 typeRail = typeRail,
                 colors = colors
             )
@@ -298,7 +360,7 @@ private fun NavigationBar(
                 label = { Label(text = textResource(R.string.folders)) },
                 icon = { Icon(imageVector = Icons.Filled.FolderCopy, contentDescription = null) },
                 checked = domain == RouteFolders.domain,
-                onClick = { facade.launchReviewFlow(); navController.toRoute(RouteFolders()) },
+                onClick = { facade.launchReviewFlow(); navController.toRoute(RouteFolders) },
                 typeRail = typeRail,
                 colors = colors
             )
@@ -308,19 +370,23 @@ private fun NavigationBar(
                 label = { Label(text = textResource(R.string.settings)) },
                 icon = { Icon(imageVector = Icons.Filled.Settings, contentDescription = null) },
                 checked = domain == RouteSettings.domain,
-                onClick = { facade.launchReviewFlow(); navController.toRoute(RouteSettings()) },
+                onClick = { facade.launchReviewFlow(); navController.toRoute(RouteSettings) },
                 typeRail = typeRail,
                 colors = colors
             )
         }
     }
+
+    // Get the current theme colors
     val colors = AppTheme.colors
     when (typeRail) {
         true -> NavigationRail(
-            modifier = modifier.width(NAV_RAIL_WIDTH),
+            modifier = modifier
+                .clip(NavRailShape)
+                .widthIn(NAV_RAIL_MIN_WIDTH),
             windowInsets = WindowInsets.statusBars,
             contentColor = colors.onBackground,
-            backgroundColor = Color.Transparent,
+            backgroundColor = colors.background(1.dp),
             elevation = 0.dp,
             content = {
                 // Display routes at the top of the navRail.
@@ -340,8 +406,8 @@ private fun NavigationBar(
                 vertical = AppTheme.padding.medium
             ) + PaddingValues(top = 16.dp),
             modifier = modifier
-                .clip(TopConcaveShape(radius = 20.dp))
-            ,
+                .heightIn(BOTTOM_NAV_MIN_HEIGHT)
+                .clip(BottomNavShape),
             content = {
                 Spacer(modifier = Modifier.weight(1f))
                 // Display routes at the contre of available space
@@ -352,138 +418,74 @@ private fun NavigationBar(
     }
 }
 
-/**
- * The shape of the content inside the scaffold when in horizontal orientation and navbar is shown.
- */
-private val HORIZONTAL_CONTENT_SHAPE =
-    RoundedCornerShape(topStartPercent = 8, bottomStartPercent = 8)
-
-/**
- * The set of domains that require the navigation bar to be shown.
- * For other domains, the navigation bar will be hidden.
- */
-private val DOMAINS_REQUIRING_NAV_BAR =
-    arrayOf(RouteTimeline.domain, RouteFolders.domain, RouteSettings.domain)
-
-/**
- * Defines the navigation graph for the application.
- */
-private val NavGraphBuilder: NavGraphBuilder.() -> Unit = {
-    // Route for handling storage permissions.
-    composable(RoutePermission) { Permission() }
-
-    // Route for the Timeline screen.
-    composable(RouteTimeline) {
-        val state = koinViewModel<TimelineViewModel>()
-        Timeline(viewState = state)
-    }
-
-    // Folders
-    composable(RouteFolders) {
-        val state = koinViewModel<FoldersViewModel>()
-        Folders(viewState = state)
-    }
-
-    // Settings
-    composable(RouteSettings) {
-        val state = koinViewModel<SettingsViewModel>()
-        Settings(viewState = state)
-    }
-
-    // Viewer
-    composable(RouteViewer) {
-        val state = koinViewModel<ViewerViewModel>()
-        Viewer(viewState = state)
-    }
-
-    // Folder - That displays files
-    composable(RouteFolder) {
-        val state = koinViewModel<FolderViewModel>()
-        Folder(viewState = state)
-    }
-
-    // Album
-    composable(RouteAlbum) {
-        val state = koinViewModel<AlbumViewModel>()
-        Album(viewState = state)
-    }
-
-    // Trash
-    composable(RouteTrash) {
-        val state = koinViewModel<TrashViewModel>()
-        Trash(viewState = state)
-    }
-}
-
-/**
- * Composable function representing the Home screen.
- *
- * @param toastHostState The [ToastHostState] used to display toasts.
- */
 @Composable
-fun Home(toastHostState: ToastHostState) {
-    // Check if light theme is preferred
-    // Create a NavController for navigation
-    val isLight = !isPreferenceDarkTheme()
-    val navController = rememberNavController()
-    // Layout Configuration
-    // Adjust layout configuration based on window size and navigation state.
-    // Hide navigation bar and uses vertical layout on smaller screens.
-    val clazz = LocalWindowSize.current
+fun Gallery(
+    toastHostState: ToastHostState,
+    navController: NavHostController,
+    // TODO- Find why i can't pass Route just an argument.
+    startDestination: () -> Route,
+) {
+    // dependencies
+    val activity = LocalView.current.context as MainActivity
+    val clazz = calculateWindowSizeClass(activity = activity)
     val current = navController.current
-    val hideNavigationBar = current?.domain !in DOMAINS_REQUIRING_NAV_BAR
-    val vertical = clazz.widthRange < Range.Medium
-    // Construct the actual content of the layout
+
+    // variables
+    val requiresNavBar = current?.domain in DOMAINS_REQUIRING_NAV_BAR
+    val portrait = clazz.portrait
+    // content
     val content = @Composable {
-        val context = LocalContext.current
-        // Load start destination based on if storage permission is set or not.
-        val granted =
-            context.isPermissionGranted(ADAPTIVE_STORAGE_PERMISSIONS[0])
-        val startDestination = if (granted) RouteTimeline else RoutePermission
-        NavHost(
-            navController = navController,
-            startDestination = startDestination.route,
-            builder = NavGraphBuilder,
-            modifier = Modifier
-                .thenIf(!vertical && !hideNavigationBar, Modifier.clip(HORIZONTAL_CONTENT_SHAPE))
-                .background(AppTheme.colors.background)
-                .fillMaxSize(),
-            enterTransition = {
-                scaleIn(tween(220, 90), 0.98f) +
-                        fadeIn(tween(700))
+        NavigationSuiteScaffold(
+            vertical = portrait,
+            toastHostState = toastHostState,
+            hideNavigationBar = !requiresNavBar,
+            background = AppTheme.colors.background,
+            // Set up the navigation bar using the NavBar composable
+            navBar = {
+                NavigationBar(
+                    !portrait,
+                    navController,
+                    Modifier.renderInSharedTransitionScopeOverlay(0.2f)
+                )
             },
-            exitTransition = { fadeOut(animationSpec = tween(700)) },
+            // Display the main content of the app using the NavGraph composable
+            content = {
+                // Load start destination based on if storage permission is set or not.
+                val granted = activity.checkSelfPermissions(REQUIRED_PERMISSIONS)
+                NavHost(
+                    navController = navController,
+                    startDestination = if (!granted) RoutePermission() else startDestination().route,
+                    builder = navGraphBuilder
+                )
+            }
         )
     }
+
+    // Check if light theme is preferred
+    val isDark = run {
+        val mode by activity.observeAsState(key = Settings.KEY_NIGHT_MODE)
+        when (mode) {
+            NightMode.YES -> true
+            NightMode.NO -> false
+            NightMode.FOLLOW_SYSTEM -> isSystemInDarkTheme()
+        }
+    }
+
     // Setup App Theme and provide necessary dependencies.
     // Provide the navController and window size class to child composable.
     AppTheme(
-        isLight = isLight,
+        isLight = !isDark,
         fontFamily = Settings.DefaultFontFamily,
         content = {
             // Provide the navController, newWindowClass through LocalComposition.
             CompositionLocalProvider(
                 LocalNavController provides navController,
-                LocalWindowSize provides clazz.remaining,
-                content = {
-                    NavigationSuiteScaffold(
-                        vertical = vertical,
-                        toastHostState = toastHostState,
-                        hideNavigationBar = hideNavigationBar,
-                        background = AppTheme.colors.background(elevation = 1.dp),
-                        // Set up the navigation bar using the NavBar composable
-                        navBar = {
-                            NavigationBar(
-                                clazz.navTypeRail,
-                                navController,
-                                Modifier.renderInSharedTransitionScopeOverlay(0.2f)
-                            )
-                        },
-                        // Display the main content of the app using the NavGraph composable
-                        content = content
-                    )
-                }
+                LocalElevationOverlay provides null,  // Disable absolute elevation.
+                LocalSystemFacade provides (activity as SystemFacade),
+                LocalDensity provides activity.density,
+                LocalWindowSize provides if (!requiresNavBar) clazz else clazz.consume(!portrait),
+                content = content
             )
-        },
+        }
     )
-}
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/zs/gallery/MainActivity.kt b/app/src/main/java/com/zs/gallery/MainActivity.kt
index ae14afa..1a0a01e 100644
--- a/app/src/main/java/com/zs/gallery/MainActivity.kt
+++ b/app/src/main/java/com/zs/gallery/MainActivity.kt
@@ -18,18 +18,24 @@
 
 package com.zs.gallery
 
+import android.annotation.SuppressLint
 import android.content.Intent
 import android.content.res.Configuration
+import android.hardware.biometrics.BiometricManager.Authenticators.BIOMETRIC_STRONG
+import android.hardware.biometrics.BiometricManager.Authenticators.DEVICE_CREDENTIAL
+import android.hardware.biometrics.BiometricPrompt
+import android.os.Build
 import android.os.Bundle
+import android.os.CancellationSignal
 import android.util.Log
 import android.view.WindowManager
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
-import androidx.compose.material.LocalElevationOverlay
+import androidx.annotation.RequiresApi
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.outlined.Downloading
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.runtime.DisposableEffect
 import androidx.compose.runtime.NonRestartableComposable
 import androidx.compose.runtime.mutableFloatStateOf
 import androidx.compose.ui.graphics.Color
@@ -40,6 +46,10 @@ import androidx.core.splashscreen.SplashScreen.Companion.installSplashScreen
 import androidx.core.view.WindowCompat
 import androidx.core.view.WindowInsetsCompat
 import androidx.lifecycle.lifecycleScope
+import androidx.navigation.NavController
+import androidx.navigation.NavDestination
+import androidx.navigation.NavHostController
+import androidx.navigation.compose.rememberNavController
 import com.google.android.play.core.appupdate.AppUpdateManagerFactory
 import com.google.android.play.core.ktx.AppUpdateResult
 import com.google.android.play.core.ktx.requestAppUpdateInfo
@@ -47,6 +57,9 @@ import com.google.android.play.core.ktx.requestReview
 import com.google.android.play.core.ktx.requestUpdateFlow
 import com.google.android.play.core.review.ReviewManagerFactory
 import com.google.firebase.Firebase
+import com.google.firebase.analytics.FirebaseAnalytics
+import com.google.firebase.analytics.analytics
+import com.google.firebase.analytics.logEvent
 import com.google.firebase.crashlytics.crashlytics
 import com.primex.core.MetroGreen
 import com.primex.core.getText2
@@ -56,14 +69,14 @@ import com.primex.preferences.Preferences
 import com.primex.preferences.longPreferenceKey
 import com.primex.preferences.observeAsState
 import com.primex.preferences.value
-import com.zs.foundation.LocalWindowSize
-import com.zs.foundation.calculateWindowSizeClass
 import com.zs.foundation.toast.Toast
 import com.zs.foundation.toast.ToastHostState
-import com.zs.gallery.common.LocalSystemFacade
 import com.zs.gallery.common.NightMode
 import com.zs.gallery.common.SystemFacade
+import com.zs.gallery.common.domain
 import com.zs.gallery.common.getPackageInfoCompat
+import com.zs.gallery.files.RouteTimeline
+import com.zs.gallery.lockscreen.RouteLockScreen
 import com.zs.gallery.settings.Settings
 import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.combine
@@ -72,6 +85,8 @@ import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
 import org.koin.android.ext.android.inject
 import kotlin.time.Duration.Companion.days
+import kotlin.time.Duration.Companion.minutes
+import android.widget.Toast as PlatformToast
 
 private const val TAG = "MainActivity"
 
@@ -95,29 +110,173 @@ private val STANDARD_REVIEW_DELAY = 5.days
 private val KEY_LAST_REVIEW_TIME =
     longPreferenceKey(TAG + "_last_review_time", 0)
 
-/**
- * Manages SplashScreen
- */
-context(ComponentActivity)
-private fun configureSplashScreen(isColdStart: Boolean) {
-    // Installs the Splash Screen provided by the SplashScreen compat library
-    installSplashScreen().let { screen ->
-        // Only animate the exit if this is a cold start of the app
-        if (!isColdStart) return@let
-    }
-}
-
 /**
  * @property inAppUpdateProgress A simple property that represents the progress of the in-app update.
  *        The progress value is a float between 0.0 and 1.0, indicating the percentage of the
  *        update that has been completed. The Float.NaN represents a default value when no update
  *        is going on.
+ * @property timeAppWentToBackground The time in mills until the app was in background state. default value -1L
+ * @property isAuthenticationRequired A boolean flag indicating whether authentication is required.
  */
-class MainActivity : ComponentActivity(), SystemFacade {
+class MainActivity : ComponentActivity(), SystemFacade, NavController.OnDestinationChangedListener {
     private val toastHostState: ToastHostState by inject()
     private val preferences: Preferences by inject()
+    private var navController: NavHostController? = null
     private val inAppUpdateProgress = mutableFloatStateOf(Float.NaN)
 
+    /**
+     * Timestamp (mills) indicating when the app last went to the background.
+     *
+     * Possible values:
+     * - `-1L`: The app has just started and hasn't been in the background yet.
+     * - `0L`: The app was launched for the first time (initial launch).
+     * - `> 0L`: The time in milliseconds when the app last entered the background.
+     */
+    private var timeAppWentToBackground = -1L
+
+    /**
+     * Checks if authentication is required.
+     *
+     * Authentication is not supported on Android versions below P.
+     *
+     * @return `true` if authentication should be shown, `false` otherwise.
+     */
+    private val isAuthenticationRequired: Boolean
+        get() {
+            // App lock is not supported on Android versions below P.
+            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.P) {
+                return false
+            }
+
+            // If the timestamp is 0L, the user has recently unlocked the app,
+            // so authentication is not required.
+            if (timeAppWentToBackground == 0L) {
+                return false
+            }
+
+            // Check the app lock timeout setting.
+            return when (val timeoutValue = preferences.value(Settings.KEY_APP_LOCK_TIME_OUT)) {
+                -1 -> false // App lock is disabled (timeout value of -1)
+                0 -> true // Immediate authentication required (timeout value of 0)
+                else -> {
+                    // Calculate the time elapsed since the app went to background.
+                    val currentTime = System.currentTimeMillis()
+                    val timeSinceBackground = currentTime - timeAppWentToBackground
+                    timeSinceBackground >= timeoutValue.minutes.inWholeMilliseconds
+                }
+            }
+
+        }
+
+    override fun onPause() {
+        super.onPause()
+        // The time when app went to background.
+        // irrespective of what value it holds update it.
+        Log.d(TAG, "onPause")
+        timeAppWentToBackground = System.currentTimeMillis()
+    }
+
+    @SuppressLint("NewApi")
+    override fun onResume() {
+        super.onResume()
+        Log.d(TAG, "onStart")
+        // Only navigate to the lock screen if authentication is required and
+        // this is not a fresh app start.
+
+        // On a fresh start, timeAppWentToBackground is -1L.
+        // If authentication is required on a fresh start, the app will be
+        // automatically navigated to the lock screen in onCreate().
+        if (timeAppWentToBackground != -1L && isAuthenticationRequired) {
+            navController?.navigate(RouteLockScreen())
+            unlock()
+        }
+    }
+
+    override fun enroll() {
+        TODO("Not yet implemented")
+    }
+
+    override fun showPlatformToast(string: Int) =
+        PlatformToast.makeText(this, getString(string), PlatformToast.LENGTH_SHORT).show()
+
+    override fun showPlatformToast(string: String) =
+        PlatformToast.makeText(this, string, PlatformToast.LENGTH_SHORT).show()
+
+    @RequiresApi(Build.VERSION_CODES.P)
+    override fun authenticate(desc: String?, onAuthenticated: () -> Unit) {
+        Log.d(TAG, "preparing to show authentication dialog.")
+        // Build the BiometricPrompt
+        val prompt = BiometricPrompt.Builder(this).apply {
+            setTitle(getString(R.string.scr_lock_screen_title))
+            setSubtitle(getString(R.string.scr_lock_screen_subtitle))
+            if (desc != null) setDescription(desc)
+            // Set allowed authenticators for Android R and above
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R)
+                setAllowedAuthenticators(BIOMETRIC_STRONG or DEVICE_CREDENTIAL)
+            // Allow device credential fallback for Android Q
+            if (Build.VERSION.SDK_INT == Build.VERSION_CODES.Q)
+                setDeviceCredentialAllowed(true)
+            // On Android P and below, BiometricPrompt crashes if a negative button is not set.
+            // We provide a "Dismiss" button to avoid the crash, but this does not offer alternative
+            // authentication (like PIN).
+            // Future versions might include support for alternative authentication on older Android versions
+            // if a compatibility library or API becomes available.
+            if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.P)
+                setNegativeButton("Dismiss", mainExecutor, { _, _ -> })
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q)
+                setConfirmationRequired(false)
+            /*if (Build.VERSION.SDK_INT >= 35) {
+                setLogoRes(R.drawable.ic_app)
+            }*/
+        }.build()
+        // Start the authentication process
+        prompt.authenticate(
+            CancellationSignal(),
+            mainExecutor,
+            object : BiometricPrompt.AuthenticationCallback() {
+                // Implement callback methods for authentication events (success, error, etc.)
+                override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult?) {
+                    showPlatformToast("Authentication Successful! Welcome back.")
+                    onAuthenticated()
+                }
+
+                override fun onAuthenticationFailed() {
+                    super.onAuthenticationFailed()
+                    showPlatformToast("Authentication Failed! Please try again or use an alternative method.")
+                }
+
+                override fun onAuthenticationError(errorCode: Int, errString: CharSequence?) {
+                    super.onAuthenticationError(errorCode, errString)
+                    showPlatformToast("Authentication Error: $errString")
+                }
+            }
+        )
+    }
+
+    @SuppressLint("NewApi")
+    override fun unlock() = authenticate(getString(R.string.src_lock_screen_desc)) {
+        val navController = navController ?: return@authenticate
+        // if it is initial app_lock update timeAppWentToBackground to 0
+        if (timeAppWentToBackground == -1L)
+            timeAppWentToBackground = 0L
+        // Check if the start destination needs to be updated
+        // Update the start destination to RouteTimeline
+        if (navController.graph.startDestinationRoute == RouteLockScreen()) {
+            Log.d(TAG, "unlock: updating start destination")
+            navController.graph.setStartDestination(RouteTimeline())
+            navController.navigate(RouteTimeline()) {
+                popUpTo(RouteLockScreen()) {
+                    inclusive = true
+                }
+            }
+            // return from here;
+            return@authenticate
+        }
+        Log.d(TAG, "unlock: poping lock_screen from graph")
+        // If the start destination is already RouteTimeline, just pop back
+        navController.popBackStack()
+    }
+
     override fun enableEdgeToEdge(
         hide: Boolean?,
         translucent: Boolean?,
@@ -133,7 +292,8 @@ class MainActivity : ComponentActivity(), SystemFacade {
         // Otherwise, show the system bars
         controller.show(WindowInsetsCompat.Type.systemBars())
         // Determine translucency based on provided value or preference
-        val translucent = translucent ?: !preferences.value(Settings.KEY_TRANSPARENT_SYSTEM_BARS)
+        val translucent =
+            translucent ?: !preferences.value(Settings.KEY_TRANSPARENT_SYSTEM_BARS)
         // Set the color for status and navigation bars based on translucency
         val color = when (translucent) {
             false -> Color.Transparent.toArgb()
@@ -180,7 +340,8 @@ class MainActivity : ComponentActivity(), SystemFacade {
         duration: Int
     ) {
         lifecycleScope.launch {
-            val action = if (action == ResourcesCompat.ID_NULL) null else resources.getText2(action)
+            val action =
+                if (action == ResourcesCompat.ID_NULL) null else resources.getText2(action)
             toastHostState.showToast(
                 resources.getText2(id = message),
                 action,
@@ -208,6 +369,7 @@ class MainActivity : ComponentActivity(), SystemFacade {
         // caused the change in config. means the system bars need to be configured again
         // but what would happen if the system bars are already configured?
         enableEdgeToEdge()
+        Log.d(TAG, "onConfigurationChanged: ${navController?.currentDestination?.route}")
     }
 
     private fun initialize() {
@@ -296,7 +458,8 @@ class MainActivity : ComponentActivity(), SystemFacade {
             // Get the first install time of the app.
             // Check if enough time has passed since the first install.
             val firstInstallTime =
-                packageManager.getPackageInfoCompat(BuildConfig.APPLICATION_ID)?.firstInstallTime ?: 0
+                packageManager.getPackageInfoCompat(BuildConfig.APPLICATION_ID)?.firstInstallTime
+                    ?: 0
             val currentTime = System.currentTimeMillis()
             if (currentTime - firstInstallTime < INITIAL_REVIEW_DELAY.inWholeMilliseconds)
                 return@launch
@@ -319,24 +482,46 @@ class MainActivity : ComponentActivity(), SystemFacade {
         }
     }
 
+    override fun onDestinationChanged(
+        controller: NavController,
+        destination: NavDestination,
+        arguments: Bundle?
+    ) {
+        // Log the event.
+        Firebase.analytics.logEvent(FirebaseAnalytics.Event.SCREEN_VIEW) {
+            // create params for the event.
+            val domain = destination.domain ?: "unknown"
+            Log.d(TAG, "onNavDestChanged: $domain")
+            param(FirebaseAnalytics.Param.SCREEN_NAME, domain)
+        }
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        // The app has started from scratch if savedInstanceState is null.
-        val isColdStart = savedInstanceState == null //why?
-
+        Log.d(TAG, "onCreate")
         // Manage SplashScreen
-        configureSplashScreen(isColdStart)
+        installSplashScreen()
         // init the heavy duty tasks in initialize()
         initialize()
-        // Configure system bars
+        // Set the content of the activity
         setContent {
-            val windowSizeClass = calculateWindowSizeClass(activity = this)
-            CompositionLocalProvider(
-                LocalWindowSize provides windowSizeClass,
-                LocalElevationOverlay provides null,  // Disable absolute elevation.
-                LocalSystemFacade provides this,
-                content = { Home(toastHostState) }
+            val navController = rememberNavController()
+            // if authentication is required move to lock screen
+            Gallery(
+                toastHostState,
+                navController,
+                { if (isAuthenticationRequired) RouteLockScreen else RouteTimeline }
             )
+
+            DisposableEffect(Unit) {
+                navController.addOnDestinationChangedListener(this@MainActivity)
+                if (isAuthenticationRequired) unlock()
+                this@MainActivity.navController = navController
+                onDispose {
+                    navController.removeOnDestinationChangedListener(this@MainActivity)
+                    this@MainActivity.navController = null
+                }
+            }
         }
     }
 }
\ No newline at end of file
diff --git a/app/src/main/java/com/zs/gallery/common/Route.kt b/app/src/main/java/com/zs/gallery/common/Route.kt
index f4ffb72..15b42c2 100644
--- a/app/src/main/java/com/zs/gallery/common/Route.kt
+++ b/app/src/main/java/com/zs/gallery/common/Route.kt
@@ -114,4 +114,5 @@ fun NavGraphBuilder.composable(
  * @see androidx.navigation.NavGraph.setStartDestination(java.lang.String)
  */
 fun <T> NavGraph.setStartDestination(route: Route) =
-    setStartDestination(route.route)
\ No newline at end of file
+    setStartDestination(route.route)
+
diff --git a/app/src/main/java/com/zs/gallery/common/SystemFacade.kt b/app/src/main/java/com/zs/gallery/common/SystemFacade.kt
index 285cef3..437b435 100644
--- a/app/src/main/java/com/zs/gallery/common/SystemFacade.kt
+++ b/app/src/main/java/com/zs/gallery/common/SystemFacade.kt
@@ -22,7 +22,9 @@ package com.zs.gallery.common
 
 import android.content.Intent
 import android.net.Uri
+import android.os.Build
 import android.os.Bundle
+import androidx.annotation.RequiresApi
 import androidx.annotation.StringRes
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.NonRestartableComposable
@@ -139,6 +141,56 @@ interface SystemFacade {
      * It considers [MIN_LAUNCH_COUNT], [MAX_DAYS_BEFORE_FIRST_REVIEW], and [MAX_DAYS_AFTER_FIRST_REVIEW] to prevent excessive prompting.
      */
     fun launchReviewFlow()
+
+    /**
+     * Unlocks the app, granting access to its content.
+     *
+     * This function initiates the authentication process, typically using biometric verification or
+     * other security measures, to unlock the app and allow the user to access its features.
+     */
+    fun unlock()
+
+    /**
+     * Initiates biometric authentication.
+     *
+     * Displays a biometric prompt to the user. If authentication is successful, the [onAuthenticated]
+     * callback will be executed. This function requires Android P (API level 28) or higher.
+     *
+     * @param onAuthenticated A callback function that will be executed upon successful authentication.
+     * @param desc A description of the authentication process. This description will be displayed
+     */
+    @RequiresApi(Build.VERSION_CODES.P)
+    fun authenticate(desc: String? = null, onAuthenticated: () -> Unit)
+
+    /**
+     * Guides the user to the system settings for biometric enrollment.
+     *
+     * This function helps users set up biometric authentication (e.g., fingerprint, face recognition)
+     * by directing them to the appropriate settings on their device. This is necessary before the app
+     * can use biometric authentication features.
+     *
+     * Requires Android P (API level 28) or higher.
+     */
+    @RequiresApi(Build.VERSION_CODES.P)
+    fun enroll()
+
+    /**
+     * Displays a toast message using the platform's default toast mechanism.
+     *
+     * This function shows a short toast message with the provided text.
+     *
+     * @param string The text message to display in the toast.
+     */
+    fun showPlatformToast(string: String)
+
+    /**
+     * Displays a toast message using the platform's default toast mechanism.
+     *
+     * This function shows a short toast message with the text from the specified string resource.
+     *
+     * @param string The string resource ID of the text message to display in the toast.
+     */
+    fun showPlatformToast(@StringRes string: Int)
 }
 
 /**
diff --git a/app/src/main/java/com/zs/gallery/impl/MainViewModel.kt b/app/src/main/java/com/zs/gallery/impl/MainViewModel.kt
index e67b919..e424ba4 100644
--- a/app/src/main/java/com/zs/gallery/impl/MainViewModel.kt
+++ b/app/src/main/java/com/zs/gallery/impl/MainViewModel.kt
@@ -363,7 +363,7 @@ abstract class MainViewModel<T>(
         provider.observer(MediaProvider.EXTERNAL_CONTENT_URI)
             .onEach { refresh() }
             .catch { exception ->
-                Log.e(TAG, "provider: ${exception.message}")
+                Log.d(TAG, "provider: ${exception.stackTraceToString()}")
                 // Handle any exceptions that occur during the flow.
                 // This might involve logging the exception using Firebase Crashlytics.
                 // Display a toast message to the user, indicating something went wrong and suggesting they report the issue.
diff --git a/app/src/main/java/com/zs/gallery/lockscreen/LockScreen.kt b/app/src/main/java/com/zs/gallery/lockscreen/LockScreen.kt
new file mode 100644
index 0000000..2c48dc5
--- /dev/null
+++ b/app/src/main/java/com/zs/gallery/lockscreen/LockScreen.kt
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2024 Zakir Sheikh
+ *
+ * Created by 2024 on 12-09-2024.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.zs.gallery.lockscreen
+
+import android.annotation.SuppressLint
+import androidx.compose.foundation.layout.size
+import androidx.compose.foundation.shape.CircleShape
+import androidx.compose.material.ButtonDefaults
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.unit.dp
+import com.primex.core.textResource
+import com.primex.material2.OutlinedButton
+import com.zs.foundation.LocalWindowSize
+import com.zs.foundation.Range
+import com.zs.gallery.R
+import com.zs.gallery.common.LocalSystemFacade
+import com.zs.gallery.common.Route
+
+object RouteLockScreen: Route
+
+@SuppressLint("NewApi")
+@Composable
+fun LockScreen() {
+    // If the permissions are not granted, show the permission screen.
+    val facade = LocalSystemFacade.current
+    com.zs.gallery.common.Placeholder(
+        iconResId = R.raw.lt_app_lock,
+        title = stringResource(R.string.scr_lock_screen_title),
+        message = textResource(R.string.src_lock_screen_desc),
+        vertical = LocalWindowSize.current.widthRange == Range.Compact,
+    ) {
+        OutlinedButton(
+            onClick = facade::unlock,
+            modifier = Modifier.size(width = 200.dp, height = 46.dp),
+            elevation = null,
+            label = stringResource(R.string.allow),
+            border = ButtonDefaults.outlinedBorder,
+            shape = CircleShape,
+            colors = ButtonDefaults.outlinedButtonColors(backgroundColor = Color.Transparent)
+        )
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/com/zs/gallery/settings/Settings.kt b/app/src/main/java/com/zs/gallery/settings/Settings.kt
index f857bb3..c023051 100644
--- a/app/src/main/java/com/zs/gallery/settings/Settings.kt
+++ b/app/src/main/java/com/zs/gallery/settings/Settings.kt
@@ -41,6 +41,7 @@ import androidx.compose.ui.graphics.RectangleShape
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.compose.ui.input.nestedscroll.nestedScroll
 import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.unit.dp
 import com.primex.core.textResource
 import com.primex.material2.DropDownPreference
@@ -219,17 +220,21 @@ private inline fun Appearance(
         title = prefFontScale.title,
         summery = prefFontScale.summery,
         icon = prefFontScale.vector,
-        steps = 11,
-        valueRange = 0.5f..1.5f,
+        // (2.0 - 0.7) / 0.1 = 13 steps
+        steps = 13,
+        valueRange = 0.7f..2.0f,
         defaultValue = prefFontScale.value,
-        onValueChange = { sliderValue ->
-            val it = (sliderValue * 10).roundToInt() / 10f
-            viewState.set(Settings.KEY_FONT_SCALE, it)
+        onValueChange = { value ->
+            val newValue = if (value < 0.76f) -1f else value
+            viewState.set(Settings.KEY_FONT_SCALE, newValue)
         },
         modifier = Modifier
             .background(AppTheme.colors.tileBackgroundColor, BottomTileShape),
         preview = {
-            Label(text = stringResource(R.string.times_factor_x_f, prefFontScale.value))
+            Label(
+                text = if (prefFontScale.value == -1f) "System" else stringResource(R.string.times_factor_x_f, prefFontScale.value),
+                fontWeight = FontWeight.Bold
+            )
         }
     )
 }
diff --git a/app/src/main/java/com/zs/gallery/settings/SettingsViewState.kt b/app/src/main/java/com/zs/gallery/settings/SettingsViewState.kt
index 8dcbe8d..4da18d7 100644
--- a/app/src/main/java/com/zs/gallery/settings/SettingsViewState.kt
+++ b/app/src/main/java/com/zs/gallery/settings/SettingsViewState.kt
@@ -26,7 +26,6 @@ import androidx.compose.ui.text.googlefonts.Font
 import androidx.compose.ui.text.googlefonts.GoogleFont
 import androidx.compose.ui.unit.dp
 import com.primex.preferences.Key
-import com.zs.gallery.common.Route
 import com.primex.preferences.StringSaver
 import com.primex.preferences.booleanPreferenceKey
 import com.primex.preferences.floatPreferenceKey
@@ -34,6 +33,19 @@ import com.primex.preferences.intPreferenceKey
 import com.primex.preferences.stringPreferenceKey
 import com.zs.gallery.R
 import com.zs.gallery.common.NightMode
+import com.zs.gallery.common.Route
+import com.zs.gallery.settings.Settings.KEY_APP_LOCK_TIME_OUT
+import com.zs.gallery.settings.Settings.KEY_DYNAMIC_GALLERY
+import com.zs.gallery.settings.Settings.KEY_FAVOURITE_FILES
+import com.zs.gallery.settings.Settings.KEY_FONT_SCALE
+import com.zs.gallery.settings.Settings.KEY_GRID_ITEM_SIZE_MULTIPLIER
+import com.zs.gallery.settings.Settings.KEY_IMMERSIVE_VIEW
+import com.zs.gallery.settings.Settings.KEY_LAUNCH_COUNTER
+import com.zs.gallery.settings.Settings.KEY_NIGHT_MODE
+import com.zs.gallery.settings.Settings.KEY_SECURE_MODE
+import com.zs.gallery.settings.Settings.KEY_TRANSPARENT_SYSTEM_BARS
+import com.zs.gallery.settings.Settings.KEY_TRASH_CAN_ENABLED
+import com.zs.gallery.settings.Settings.STANDARD_TILE_SIZE
 
 object RouteSettings : Route
 
@@ -45,6 +57,9 @@ private val provider by lazy {
     )
 }
 
+private val OutfitFontFamily = FontFamily("Outfit")
+val FontFamily.Companion.OutfitFontFamily get() = com.zs.gallery.settings.OutfitFontFamily
+
 /**
  * Creates a [FontFamily] from the given Google Font name.
  *
@@ -80,21 +95,87 @@ private fun FontFamily(name: String): FontFamily {
     )
 }
 
+/**
+ * Immutable data class representing a preference.
+ *
+ * @property value The value of the preference.
+ * @property title The title text of the preference.
+ * @property vector The optional vector image associated with the preference.
+ * @property summery The optional summary text of the preference.
+ * @param P The type of the preference value.
+ */
+@Stable
+data class Preference<out P>(
+    val value: P,
+    @JvmField val title: CharSequence,
+    val vector: ImageVector? = null,
+    @JvmField val summery: CharSequence? = null,
+)
 
-object Settings {
+interface SettingsViewState {
+    val nightMode: Preference<NightMode>
+    val trashCanEnabled: Preference<Boolean>
+    val gridItemSizeMultiplier: Preference<Float>
+    val liveGallery: Preference<Boolean>
+    val fontScale: Preference<Float>
+
+    val isSystemBarsTransparent: Preference<Boolean>
+    val immersiveView: Preference<Boolean>
+    val secureMode: Preference<Boolean>
 
+    fun <S, O> set(key: Key<S, O>, value: O)
+}
+
+/**
+ * ## Settings
+ *
+ * This object contains various preference keys and their default values used throughout the app.
+ *
+ * @property STANDARD_TILE_SIZE The default min size of the single cell in grid.
+ * @property KEY_NIGHT_MODE Preference key for the night mode strategy [NightMode].
+ * @property KEY_TRASH_CAN_ENABLED Preference key for enabling/disabling the trash can feature
+ *                                (boolean). When enabled, deleted items are moved to a trashcan
+ *                                instead of being permanently deleted.
+ * @property KEY_GRID_ITEM_SIZE_MULTIPLIER Grid Size Multiplier. Preference key for the grid item
+ *                                         size multiplier (float between 0.6 and 1.5). Controls
+ *                                         the size of grid items based on user preference.
+ * @property KEY_DYNAMIC_GALLERY Preference key for enabling/disabling live gallery mode (boolean).
+ *                              When enabled, videos in the gallery autoplay while browsing.
+ * @property KEY_FONT_SCALE Font Scale Preference. This constant represents the scaling factor
+ *                          applied to the system font. Users can adjust this value to control
+ *                          the size of the font, with the default being the system default font
+ *                          size. The acceptable range is from 1.0f to 2.0f (twice the system
+ *                          default size).
+ * @property KEY_TRANSPARENT_SYSTEM_BARS Preference key for controlling the appearance of system
+ *                                       bars (boolean). When enabled, system bars become
+ *                                       transparent. When disabled, a dark background is applied
+ *                                       to the status bar.
+ * @property KEY_IMMERSIVE_VIEW Preference key for enabling/disabling immersive view mode (boolean).
+ *                              When enabled, system bars are hidden to provide a more immersive
+ *                              experience. When disabled, system bars are shown.
+ * @property KEY_FAVOURITE_FILES Preference key for enabling/disabling immersive view mode (boolean).
+ *                               When enabled, system bars are hidden to provide a more immersive
+ *                               experience. When disabled, system bars are shown.
+ * @property KEY_SECURE_MODE Preference key for enabling/disabling secure mode (boolean). When
+ *                           enabled, the app's content is obscured in the app preview,
+ *                           enhancing privacy.
+ * @property KEY_LAUNCH_COUNTER The counter counts the number of times this app was launched.
+ * @property KEY_APP_LOCK_TIME_OUT Representing the timeout duration (in minutes) for app lock.
+ * This preference determines how long the app can be in the background
+ * before the user needs to authenticate to regain access.
+ *
+ * Possible values:
+ *
+ * - `-1`: App lock is disabled.
+ * - `0`:  The app locks immediately when it enters the background.
+ * - `1`:  The app locks after 1 minute in the background.
+ * - `30`: The app locks after 30 minutes in the background.
+ * - ... and so on.
+ */
+object Settings {
     // The keys for the preferences
     private const val PREFIX = "global"
-
-    /**
-     * The default min size of the single cell in grid.
-     */
     val STANDARD_TILE_SIZE = 100.dp
-
-    /**
-     * Preference key for the night mode setting (String).
-     * Possible values: "on", "off","system"
-     */
     val KEY_NIGHT_MODE =
         stringPreferenceKey(
             "${PREFIX}_night_mode",
@@ -109,54 +190,17 @@ object Settings {
                 }
             }
         )
-
-    /**
-     * Preference key for enabling/disabling the trash can feature (boolean).
-     * When enabled, deleted items are moved to a trashcan instead of being permanently deleted.
-     */
     val KEY_TRASH_CAN_ENABLED =
         booleanPreferenceKey(PREFIX + "_trash_can_enabled", defaultValue = true)
-
-    /**
-     * Grid Size Multiplier.
-     * Preference key for the grid item size multiplier (float between 0.6 and 1.5).
-     * Controls the size of grid items based on user preference.
-     */
     val KEY_GRID_ITEM_SIZE_MULTIPLIER =
         floatPreferenceKey(PREFIX + "_grid_item_size_multiplier", defaultValue = 1.0f)
-
-    /**
-     * Preference key for enabling/disabling live gallery mode (boolean).
-     * When enabled, videos in the gallery autoplay while browsing.
-     */
     val KEY_DYNAMIC_GALLERY =
         booleanPreferenceKey(PREFIX + "_dynamic_gallery", defaultValue = true)
-
-    /**
-     * Font Scale Preference.
-     *
-     * This constant represents the scaling factor applied to the system font.
-     * Users can adjust this value to control the size of the font, with the default being the system default font size.
-     * The acceptable range is from 1.0f to 2.0f (twice the system default size).
-     */
     val KEY_FONT_SCALE = floatPreferenceKey(PREFIX + "_font_scale", -1f)
-
-    /**
-     * Preference key for controlling the appearance of system bars (boolean).
-     * When enabled, system bars become transparent.
-     * When disabled, a dark background is applied to the status bar.
-     */
     val KEY_TRANSPARENT_SYSTEM_BARS =
         booleanPreferenceKey(PREFIX + "_transparent_system_bars", defaultValue = false)
-
     val KEY_IMMERSIVE_VIEW =
         booleanPreferenceKey(PREFIX + "_immersive_view", defaultValue = false)
-
-    /**
-     * Preference key for enabling/disabling immersive view mode (boolean).
-     * When enabled, system bars are hidden to provide a more immersive experience.
-     * When disabled, system bars are shown.
-     */
     val KEY_FAVOURITE_FILES =
         stringPreferenceKey(
             "${PREFIX}_favourite_files",
@@ -173,56 +217,14 @@ object Settings {
                 }
             }
         )
-
-    /**
-     * Preference key for enabling/disabling secure mode (boolean).
-     * When enabled, the app's content is obscured in theapp preview, enhancing privacy.
-     */
     val KEY_SECURE_MODE =
         booleanPreferenceKey(PREFIX + "_secure_gallery", defaultValue = false)
-
-    /**
-     * The counter counts the number of times this app was launched.
-     */
     val KEY_LAUNCH_COUNTER =
-        intPreferenceKey( PREFIX + "_launch_counter", 0)
-
-    // Prompt
-    // Nunito Sans
-    // Ubuntu
-    // Kanit
-    val OutfitFontFamily = FontFamily("Outfit")
-    val DefaultFontFamily = FontFamily.Default
-    val DancingScriptFontFamily = FontFamily.Cursive
-}
-
-/**
- * Immutable data class representing a preference.
- *
- * @property value The value of the preference.
- * @property title The title text of the preference.
- * @property vector The optional vector image associated with the preference.
- * @property summery The optional summary text of the preference.
- * @param P The type of the preference value.
- */
-@Stable
-data class Preference<out P>(
-    val value: P,
-    @JvmField val title: CharSequence,
-    val vector: ImageVector? = null,
-    @JvmField val summery: CharSequence? = null,
-)
+        intPreferenceKey(PREFIX + "_launch_counter", 0)
+    val KEY_APP_LOCK_TIME_OUT =
+        intPreferenceKey("${PREFIX}_app_lock_time_out", 0)
 
-interface SettingsViewState {
-    val nightMode: Preference<NightMode>
-    val trashCanEnabled: Preference<Boolean>
-    val gridItemSizeMultiplier: Preference<Float>
-    val liveGallery: Preference<Boolean>
-    val fontScale: Preference<Float>
 
-    val isSystemBarsTransparent: Preference<Boolean>
-    val immersiveView: Preference<Boolean>
-    val secureMode: Preference<Boolean>
+    val DefaultFontFamily get() = FontFamily.Default
+}
 
-    fun <S, O> set(key: Key<S, O>, value: O)
-}
\ No newline at end of file
diff --git a/app/src/main/res/raw/lt_app_lock.lottie b/app/src/main/res/raw/lt_app_lock.lottie
new file mode 100644
index 0000000..87f2f50
Binary files /dev/null and b/app/src/main/res/raw/lt_app_lock.lottie differ
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index eb019e3..7365879 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -107,5 +107,8 @@
     <string name="msg_new_update_downloaded">Update ready! Installation can proceed now.</string>
     <string name="install">Install</string>
     <string name="pref_app_version">App Version</string>
+    <string name="scr_lock_screen_title">Verify Your Identity</string>
+    <string name="scr_lock_screen_subtitle">Authenticate with Biometrics</string>
+    <string name="src_lock_screen_desc">Authenticate with your fingerprint or facial recognition to continue. This step is crucial for safeguarding your data.</string>
 
 </resources>
\ No newline at end of file
diff --git a/domain/src/main/java/com/zs/domain/store/MediaProviderImpl.kt b/domain/src/main/java/com/zs/domain/store/MediaProviderImpl.kt
index 0d8b10f..84fffc8 100644
--- a/domain/src/main/java/com/zs/domain/store/MediaProviderImpl.kt
+++ b/domain/src/main/java/com/zs/domain/store/MediaProviderImpl.kt
@@ -30,6 +30,7 @@ import android.net.Uri
 import android.os.Build
 import android.provider.MediaStore
 import android.util.Log
+import android.webkit.MimeTypeMap
 import androidx.activity.ComponentActivity
 import androidx.activity.result.ActivityResult
 import androidx.activity.result.ActivityResultLauncher
@@ -69,11 +70,11 @@ private val Cursor.toMediaFile: MediaFile
     inline get() {
         return MediaFile(
             id = getLong(0),
-            name = getString(1),
+            name = getString(1) ?: "",
             dateAdded = getLong(2) * 1000,
             dateModified = getLong(3) * 1000,
             size = getLong(4),
-            mimeType = getString(5),
+            mimeType = getString(5) ?: "",
             orientation = getInt(6),
             height = getInt(7),
             width = getInt(8),
@@ -86,11 +87,11 @@ private val Cursor.toMediaFile: MediaFile
 private val Cursor.toTrashedFile: Trashed
     inline get() = Trashed(
         id = getLong(0),
-        name = getString(1),
+        name = getString(1) ?: "",
         expires = getLong(2) * 1000,
-        path = getString(3),
+        path = getString(3) ?: "",
         size = getLong(4),
-        mimeType = getString(5),
+        mimeType = getString(5) ?: "",
         duration = getInt(6)
     )
 
diff --git a/foundation/src/main/java/com/zs/foundation/Utils.kt b/foundation/src/main/java/com/zs/foundation/Utils.kt
index 11a13c6..3c7023b 100644
--- a/foundation/src/main/java/com/zs/foundation/Utils.kt
+++ b/foundation/src/main/java/com/zs/foundation/Utils.kt
@@ -17,6 +17,11 @@ import kotlin.contracts.contract
 fun Context.isPermissionGranted(permission: String) =
     ContextCompat.checkSelfPermission(this, permission) == PackageManager.PERMISSION_GRANTED
 
+/**
+ * @see isPermissionGranted
+ */
+fun Context.checkSelfPermissions(values: List<String>) =
+    values.all { isPermissionGranted(it) }
 
 /**
  * Conditionally applies another [Modifier] if the given [condition] is true.
diff --git a/foundation/src/main/java/com/zs/foundation/shapes/EndConcaveShape.kt b/foundation/src/main/java/com/zs/foundation/shapes/EndConcaveShape.kt
new file mode 100644
index 0000000..d0dd28f
--- /dev/null
+++ b/foundation/src/main/java/com/zs/foundation/shapes/EndConcaveShape.kt
@@ -0,0 +1,34 @@
+package com.zs.foundation.shapes
+
+import androidx.compose.ui.geometry.Size
+import androidx.compose.ui.graphics.Outline
+import androidx.compose.ui.graphics.Path
+import androidx.compose.ui.graphics.Shape
+import androidx.compose.ui.unit.Density
+import androidx.compose.ui.unit.Dp
+import androidx.compose.ui.unit.LayoutDirection
+
+private const val TAG = "EndConcaveShape"
+
+/**
+ * A shape that represents a rectangle with a concave top.
+ *
+ * @param radius the radius of the concave curve at the top of the shape.
+ */
+class EndConcaveShape(private val radius: Dp) : Shape {
+    override fun createOutline(size: Size, layoutDirection: LayoutDirection, density: Density): Outline {
+        val (w, h) = size
+        val radiusPx = with(density) { radius.toPx() }
+
+        val path = Path().apply {
+            moveTo(w, 0f)
+            quadraticTo(w -radiusPx, 0f, w - radiusPx, radiusPx)
+            lineTo(w-radiusPx, h- radiusPx)
+            quadraticTo(w - radiusPx, h, w, h)
+            lineTo(0f, h)
+            lineTo(0f, 0f)
+            lineTo(w, 0f)
+        }
+        return Outline.Generic(path)
+    }
+}
\ No newline at end of file
diff --git a/gradle/libs.versions.toml b/gradle/libs.versions.toml
index b3ef9dd..3f9ea92 100644
--- a/gradle/libs.versions.toml
+++ b/gradle/libs.versions.toml
@@ -16,6 +16,7 @@ crashanlytics = { id = "com.google.firebase.crashlytics", version = "3.0.2" }
 
 [libraries]
 accompanist-permissions = { module = "com.google.accompanist:accompanist-permissions", version = "0.36.0" }
+androidx-biometric-ktx = { module = "androidx.biometric:biometric-ktx", version = "1.4.0-alpha02" }
 androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version = "1.13.1" }
 androidx-exifinterface = { module = "androidx.exifinterface:exifinterface", version = "1.3.7" }
 androidx-ui = { group = "androidx.compose.ui", name = "ui", version.ref = "compose" }