增加深色模式

android/app/src/main/java/com/memory/app/MainActivity.kt

@@ -14,6 +14,8 @@ import coil.Coil
 import coil.ImageLoader
 import coil.disk.DiskCache
 import coil.memory.MemoryCache
+import com.memory.app.data.ThemeManager
+import com.memory.app.data.ThemeMode
 import com.memory.app.data.model.User
 import com.memory.app.data.repository.AuthRepository
 import com.memory.app.ui.navigation.MainNavigation
@@ -25,11 +27,14 @@ import okhttp3.OkHttpClient
 
 class MainActivity : ComponentActivity() {
     private lateinit var authRepository: AuthRepository
+    private lateinit var themeManager: ThemeManager
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         enableEdgeToEdge()
 
+        themeManager = ThemeManager(this)
+
         // 配置 Coil 图片加载器
         val imageLoader = ImageLoader.Builder(this)
             .okHttpClient {
@@ -55,7 +60,10 @@ class MainActivity : ComponentActivity() {
         authRepository = AuthRepository(this)
 
         setContent {
-            MemoryTheme {
+            val themeMode by themeManager.themeMode.collectAsState()
+            val isDarkTheme = themeMode == ThemeMode.DARK
+            
+            MemoryTheme(darkTheme = isDarkTheme) {
                 Surface(
                     modifier = Modifier.fillMaxSize(),
                     color = MaterialTheme.colorScheme.background
@@ -126,12 +134,16 @@ class MainActivity : ComponentActivity() {
                                 user = currentUser,
                                 postCount = 0,
                                 likeCount = 0,
+                                isDarkTheme = isDarkTheme,
                                 onLogout = {
                                     lifecycleScope.launch {
                                         authRepository.logout()
                                         isLoggedIn = false
                                         currentUser = null
                                     }
+                                },
+                                onToggleTheme = {
+                                    themeManager.toggleTheme()
                                 }
                             )
                         }

android/app/src/main/java/com/memory/app/ui/components/PostCard.kt

@@ -60,7 +60,7 @@ fun PostCard(
     Column(
         modifier = modifier
             .fillMaxWidth()
-            .background(Color.White)
+            .background(MaterialTheme.colorScheme.surface)
             .clickable(onClick = onPostClick)
             .padding(horizontal = 20.dp, vertical = 20.dp)
     ) {
@@ -70,7 +70,7 @@ fun PostCard(
                 modifier = Modifier
                     .size(40.dp)
                     .clip(CircleShape)
-                    .background(Slate100),
+                    .background(MaterialTheme.colorScheme.surfaceVariant),
                 contentAlignment = Alignment.Center
             ) {
                 if (post.user?.avatarUrl?.isNotEmpty() == true) {
@@ -83,7 +83,7 @@ fun PostCard(
                 } else {
                     Text(
                         text = post.user?.nickname?.firstOrNull()?.toString() ?: "?",
-                        color = Slate600,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
                         fontWeight = FontWeight.Bold,
                         fontSize = 16.sp
                     )
@@ -99,7 +99,7 @@ fun PostCard(
                         text = post.user?.nickname ?: post.user?.username ?: "",
                         fontWeight = FontWeight.Bold,
                         fontSize = 15.sp,
-                        color = Slate900
+                        color = MaterialTheme.colorScheme.onSurface
                     )
                     // 认证徽章
                     Spacer(modifier = Modifier.width(4.dp))
@@ -112,13 +112,13 @@ fun PostCard(
                     Text(
                         text = " · ${TimeUtils.formatRelative(post.createdAt)}",
                         fontSize = 12.sp,
-                        color = Slate400
+                        color = MaterialTheme.colorScheme.onSurfaceVariant
                     )
                     if (post.updatedAt != null) {
                         Text(
                             text = " · 已编辑",
                             fontSize = 12.sp,
-                            color = Slate400
+                            color = MaterialTheme.colorScheme.onSurfaceVariant
                         )
                     }
                 }
@@ -130,7 +130,7 @@ fun PostCard(
                     text = post.content,
                     fontSize = 15.sp,
                     lineHeight = 22.sp,
-                    color = Slate800
+                    color = MaterialTheme.colorScheme.onSurface
                 )
 
                 // Media
@@ -154,7 +154,7 @@ fun PostCard(
                         post.reactions.take(5).forEach { reaction ->
                             Surface(
                                 shape = RoundedCornerShape(16.dp),
-                                color = if (reaction.reacted) Brand500.copy(alpha = 0.1f) else Slate100,
+                                color = if (reaction.reacted) Brand500.copy(alpha = 0.1f) else MaterialTheme.colorScheme.surfaceVariant,
                                 modifier = Modifier.clickable { onReactionClick(reaction.emoji) }
                             ) {
                                 Row(
@@ -167,7 +167,7 @@ fun PostCard(
                                         text = reaction.count.toString(),
                                         fontSize = 12.sp,
                                         fontWeight = FontWeight.Medium,
-                                        color = if (reaction.reacted) Brand500 else Slate600
+                                        color = if (reaction.reacted) Brand500 else MaterialTheme.colorScheme.onSurfaceVariant
                                     )
                                 }
                             }
@@ -178,6 +178,8 @@ fun PostCard(
                 Spacer(modifier = Modifier.height(16.dp))
 
                 // Actions Row
+                val actionTint = MaterialTheme.colorScheme.onSurfaceVariant
+                val disabledTint = MaterialTheme.colorScheme.outlineVariant
                 Row(
                     modifier = Modifier.fillMaxWidth(),
                     horizontalArrangement = Arrangement.SpaceBetween,
@@ -188,7 +190,7 @@ fun PostCard(
                         icon = Icons.Outlined.ChatBubbleOutline,
                         count = post.commentCount,
                         onClick = onCommentClick,
-                        tint = Slate400
+                        tint = actionTint
                     )
 
                     // Edit (only show if user owns the post)
@@ -196,13 +198,13 @@ fun PostCard(
                         ActionButton(
                             icon = Icons.Outlined.Edit,
                             onClick = { onEditClick(post) },
-                            tint = Slate400
+                            tint = actionTint
                         )
                     } else {
                         ActionButton(
                             icon = Icons.Outlined.Edit,
                             onClick = { },
-                            tint = Slate200
+                            tint = disabledTint
                         )
                     }
 
@@ -211,14 +213,14 @@ fun PostCard(
                         icon = if (post.liked) Icons.Filled.Favorite else Icons.Outlined.FavoriteBorder,
                         count = post.likeCount,
                         onClick = onLikeClick,
-                        tint = if (post.liked) LikeRed else Slate400
+                        tint = if (post.liked) LikeRed else actionTint
                     )
 
                     // Emoji - using Mood icon like design
                     ActionButton(
                         icon = Icons.Outlined.Mood,
                         onClick = { showEmojiPicker = true },
-                        tint = Slate400
+                        tint = actionTint
                     )
                 }
             }
@@ -307,7 +309,7 @@ fun EmojiPickerDialog(
     ) {
         Surface(
             shape = RoundedCornerShape(28.dp),
-            color = Color.White,
+            color = MaterialTheme.colorScheme.surface,
             shadowElevation = 16.dp,
             modifier = Modifier
                 .fillMaxWidth()
@@ -332,7 +334,7 @@ fun EmojiPickerDialog(
                         text = "选择表情",
                         fontWeight = FontWeight.Bold,
                         fontSize = 20.sp,
-                        color = Slate900
+                        color = MaterialTheme.colorScheme.onSurface
                     )
                     Spacer(modifier = Modifier.weight(1f))
                     IconButton(
@@ -342,7 +344,7 @@ fun EmojiPickerDialog(
                         Icon(
                             imageVector = Icons.Outlined.Close,
                             contentDescription = "关闭",
-                            tint = Slate400,
+                            tint = MaterialTheme.colorScheme.onSurfaceVariant,
                             modifier = Modifier.size(20.dp)
                         )
                     }
@@ -391,7 +393,7 @@ fun EditPostDialog(
     Dialog(onDismissRequest = onDismiss) {
         Surface(
             shape = RoundedCornerShape(20.dp),
-            color = Color.White,
+            color = MaterialTheme.colorScheme.surface,
             tonalElevation = 8.dp,
             modifier = Modifier.fillMaxWidth()
         ) {
@@ -400,7 +402,7 @@ fun EditPostDialog(
                     text = "编辑帖子",
                     fontWeight = FontWeight.Bold,
                     fontSize = 18.sp,
-                    color = Slate900,
+                    color = MaterialTheme.colorScheme.onSurface,
                     modifier = Modifier.padding(bottom = 16.dp)
                 )
                 
@@ -410,10 +412,10 @@ fun EditPostDialog(
                     modifier = Modifier
                         .fillMaxWidth()
                         .heightIn(min = 120.dp),
-                    placeholder = { Text("写点什么...", color = Slate400) },
+                    placeholder = { Text("写点什么...", color = MaterialTheme.colorScheme.onSurfaceVariant) },
                     colors = OutlinedTextFieldDefaults.colors(
                         focusedBorderColor = Brand500,
-                        unfocusedBorderColor = Slate200
+                        unfocusedBorderColor = MaterialTheme.colorScheme.outline
                     ),
                     shape = RoundedCornerShape(12.dp)
                 )
@@ -425,7 +427,7 @@ fun EditPostDialog(
                     horizontalArrangement = Arrangement.End
                 ) {
                     TextButton(onClick = onDismiss) {
-                        Text("取消", color = Slate500)
+                        Text("取消", color = MaterialTheme.colorScheme.onSurfaceVariant)
                     }
                     Spacer(modifier = Modifier.width(8.dp))
                     Button(

android/app/src/main/java/com/memory/app/ui/navigation/Navigation.kt

@@ -47,7 +47,9 @@ fun MainNavigation(
     user: User?,
     postCount: Int,
     likeCount: Int,
-    onLogout: () -> Unit
+    isDarkTheme: Boolean = false,
+    onLogout: () -> Unit,
+    onToggleTheme: () -> Unit = {}
 ) {
     val navController = rememberNavController()
     var showCreatePost by remember { mutableStateOf(false) }
@@ -114,6 +116,7 @@ fun MainNavigation(
                     postCount = profilePostCount.takeIf { it > 0 } ?: postCount,
                     likeCount = profileLikeCount.takeIf { it > 0 } ?: likeCount,
                     dayCount = profileDayCount,
+                    isDarkTheme = isDarkTheme,
                     onEditProfile = { },
                     onLogout = onLogout,
                     onUpdateNickname = { nickname ->
@@ -121,7 +124,8 @@ fun MainNavigation(
                     },
                     onUpdateAvatar = { uri ->
                         profileViewModel.updateAvatar(context, uri)
-                    }
+                    },
+                    onToggleTheme = onToggleTheme
                 )
             }
 
@@ -175,11 +179,11 @@ fun MainNavigation(
                 modifier = Modifier
                     .fillMaxWidth()
                     .align(androidx.compose.ui.Alignment.BottomCenter),
-                color = Color.White,
+                color = MaterialTheme.colorScheme.surface,
                 shadowElevation = 0.dp
             ) {
                 Column {
-                    HorizontalDivider(color = Slate100, thickness = 1.dp)
+                    HorizontalDivider(color = MaterialTheme.colorScheme.outlineVariant, thickness = 1.dp)
                     Row(
                         modifier = Modifier
                             .fillMaxWidth()
@@ -209,7 +213,7 @@ fun MainNavigation(
                                 Icon(
                                     imageVector = if (selected) screen.selectedIcon else screen.unselectedIcon,
                                     contentDescription = screen.title,
-                                    tint = if (selected) Brand500 else Slate300,
+                                    tint = if (selected) Brand500 else Slate400,
                                     modifier = Modifier.size(24.dp)
                                 )
                             }

android/app/src/main/java/com/memory/app/ui/screen/ArchiveScreen.kt

@@ -65,14 +65,14 @@ fun ArchiveScreen(
     Column(
         modifier = Modifier
             .fillMaxSize()
-            .background(Color.White)
+            .background(MaterialTheme.colorScheme.background)
     ) {
         // Header
         Text(
             text = "归档",
             fontSize = 24.sp,
             fontWeight = FontWeight.Bold,
-            color = Slate900,
+            color = MaterialTheme.colorScheme.onBackground,
             modifier = Modifier
                 .statusBarsPadding()
                 .padding(horizontal = 20.dp, vertical = 16.dp)
@@ -158,12 +158,12 @@ fun ArchiveScreen(
                             text = "${selectedYear}年 ${getLastMonthOfQuarter(selectedQuarter)}月",
                             fontSize = 14.sp,
                             fontWeight = FontWeight.Bold,
-                            color = Slate900
+                            color = MaterialTheme.colorScheme.onSurface
                         )
                         Text(
                             text = "共${recentPosts.size}条",
                             fontSize = 12.sp,
-                            color = Slate400
+                            color = MaterialTheme.colorScheme.onSurfaceVariant
                         )
                     }
                 }
@@ -242,8 +242,8 @@ private fun StatCard(
     Column(
         modifier = modifier
             .clip(RoundedCornerShape(16.dp))
-            .background(Slate50)
-            .border(1.dp, Slate100, RoundedCornerShape(16.dp))
+            .background(MaterialTheme.colorScheme.surfaceVariant)
+            .border(1.dp, MaterialTheme.colorScheme.outline, RoundedCornerShape(16.dp))
             .padding(12.dp),
         horizontalAlignment = Alignment.CenterHorizontally
     ) {
@@ -258,13 +258,13 @@ private fun StatCard(
             text = value,
             fontSize = 20.sp,
             fontWeight = FontWeight.Bold,
-            color = Slate900
+            color = MaterialTheme.colorScheme.onSurface
         )
         Text(
             text = label,
             fontSize = 10.sp,
             fontWeight = FontWeight.Bold,
-            color = Slate400,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
             letterSpacing = 0.5.sp
         )
     }
@@ -290,7 +290,7 @@ private fun QuarterSelector(
             Icon(
                 Icons.AutoMirrored.Filled.KeyboardArrowLeft,
                 contentDescription = "上一季度",
-                tint = Slate400,
+                tint = MaterialTheme.colorScheme.onSurfaceVariant,
                 modifier = Modifier.size(20.dp)
             )
         }
@@ -300,13 +300,13 @@ private fun QuarterSelector(
                 text = "${year}年",
                 fontSize = 12.sp,
                 fontWeight = FontWeight.Bold,
-                color = Slate400
+                color = MaterialTheme.colorScheme.onSurfaceVariant
             )
             Text(
                 text = getQuarterMonthRange(quarter),
                 fontSize = 20.sp,
                 fontWeight = FontWeight.Bold,
-                color = Slate900
+                color = MaterialTheme.colorScheme.onSurface
             )
         }
 
@@ -318,7 +318,7 @@ private fun QuarterSelector(
             Icon(
                 Icons.AutoMirrored.Filled.KeyboardArrowRight,
                 contentDescription = "下一季度",
-                tint = if (canGoNext) Slate400 else Slate200,
+                tint = if (canGoNext) MaterialTheme.colorScheme.onSurfaceVariant else MaterialTheme.colorScheme.outlineVariant,
                 modifier = Modifier.size(20.dp)
             )
         }
@@ -534,13 +534,13 @@ private fun DatePostItem(
                 text = dayOfWeek,
                 fontSize = 12.sp,
                 fontWeight = FontWeight.Bold,
-                color = Slate400
+                color = MaterialTheme.colorScheme.onSurfaceVariant
             )
             Text(
                 text = date.dayOfMonth.toString(),
                 fontSize = 18.sp,
                 fontWeight = FontWeight.Bold,
-                color = Slate900
+                color = MaterialTheme.colorScheme.onSurface
             )
         }
 
@@ -550,12 +550,12 @@ private fun DatePostItem(
         Surface(
             modifier = Modifier.weight(1f),
             shape = RoundedCornerShape(12.dp),
-            color = Slate50
+            color = MaterialTheme.colorScheme.surfaceVariant
         ) {
             Text(
                 text = post.content.take(30) + if (post.content.length > 30) "..." else "",
                 fontSize = 14.sp,
-                color = Slate600,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
                 maxLines = 1,
                 overflow = TextOverflow.Ellipsis,
                 modifier = Modifier.padding(12.dp)
@@ -577,7 +577,7 @@ private fun DatePostsSheet(
     ModalBottomSheet(
         onDismissRequest = onDismiss,
         sheetState = sheetState,
-        containerColor = Color.White
+        containerColor = MaterialTheme.colorScheme.surface
     ) {
         Column(
             modifier = Modifier
@@ -595,16 +595,16 @@ private fun DatePostsSheet(
                     text = date,
                     fontSize = 18.sp,
                     fontWeight = FontWeight.Bold,
-                    color = Slate900
+                    color = MaterialTheme.colorScheme.onSurface
                 )
                 Text(
                     text = "${posts.size}条记录",
                     fontSize = 14.sp,
-                    color = Slate400
+                    color = MaterialTheme.colorScheme.onSurfaceVariant
                 )
             }
 
-            HorizontalDivider(color = Slate100)
+            HorizontalDivider(color = MaterialTheme.colorScheme.outlineVariant)
 
             if (posts.isEmpty()) {
                 Box(
@@ -615,7 +615,7 @@ private fun DatePostsSheet(
                 ) {
                     Text(
                         text = "这一天没有记录",
-                        color = Slate500
+                        color = MaterialTheme.colorScheme.onSurfaceVariant
                     )
                 }
             } else {
@@ -630,7 +630,7 @@ private fun DatePostsSheet(
                             onCommentClick = { onPostClick(post.id) },
                             onReactionClick = { }
                         )
-                        HorizontalDivider(color = Slate100, thickness = 1.dp)
+                        HorizontalDivider(color = MaterialTheme.colorScheme.outlineVariant, thickness = 1.dp)
                     }
                 }
             }

android/app/src/main/java/com/memory/app/ui/screen/HomeScreen.kt

@@ -51,13 +51,13 @@ fun HomeScreen(
     Box(
         modifier = Modifier
             .fillMaxSize()
-            .background(Slate50.copy(alpha = 0.5f))
+            .background(MaterialTheme.colorScheme.background)
     ) {
         Column(modifier = Modifier.fillMaxSize()) {
             // Sticky Header
             Surface(
                 modifier = Modifier.fillMaxWidth(),
-                color = Color.White.copy(alpha = 0.9f),
+                color = MaterialTheme.colorScheme.surface.copy(alpha = 0.95f),
                 shadowElevation = 0.dp
             ) {
                 Row(
@@ -74,7 +74,7 @@ fun HomeScreen(
                             .size(36.dp)
                             .shadow(2.dp, CircleShape)
                             .clip(CircleShape)
-                            .background(Slate200),
+                            .background(MaterialTheme.colorScheme.surfaceVariant),
                         contentAlignment = Alignment.Center
                     ) {
                         if (user?.avatarUrl?.isNotEmpty() == true) {
@@ -87,7 +87,7 @@ fun HomeScreen(
                         } else {
                             Text(
                                 text = user?.nickname?.firstOrNull()?.toString() ?: "?",
-                                color = Slate600,
+                                color = MaterialTheme.colorScheme.onSurfaceVariant,
                                 fontWeight = FontWeight.Bold,
                                 fontSize = 14.sp
                             )
@@ -99,7 +99,7 @@ fun HomeScreen(
                         text = "时间轴",
                         fontSize = 18.sp,
                         fontWeight = FontWeight.Bold,
-                        color = Slate800
+                        color = MaterialTheme.colorScheme.onSurface
                     )
 
                     // Bell Icon
@@ -110,7 +110,7 @@ fun HomeScreen(
                         Icon(
                             Icons.Outlined.Notifications,
                             contentDescription = "通知",
-                            tint = Slate400,
+                            tint = MaterialTheme.colorScheme.onSurfaceVariant,
                             modifier = Modifier.size(20.dp)
                         )
                     }
@@ -118,7 +118,7 @@ fun HomeScreen(
             }
 
             // Divider
-            HorizontalDivider(color = Slate100, thickness = 1.dp)
+            HorizontalDivider(color = MaterialTheme.colorScheme.outlineVariant, thickness = 1.dp)
 
             // Content
             PullToRefreshBox(
@@ -146,7 +146,7 @@ fun HomeScreen(
                                 modifier = Modifier
                                     .size(64.dp)
                                     .clip(CircleShape)
-                                    .background(Slate100),
+                                    .background(MaterialTheme.colorScheme.surfaceVariant),
                                 contentAlignment = Alignment.Center
                             ) {
                                 Text(text = "📝", fontSize = 28.sp)
@@ -156,13 +156,13 @@ fun HomeScreen(
                                 text = "还没有帖子",
                                 fontSize = 16.sp,
                                 fontWeight = FontWeight.Medium,
-                                color = Slate800
+                                color = MaterialTheme.colorScheme.onSurface
                             )
                             Spacer(modifier = Modifier.height(4.dp))
                             Text(
                                 text = "点击右下角按钮发布第一条",
                                 fontSize = 14.sp,
-                                color = Slate500
+                                color = MaterialTheme.colorScheme.onSurfaceVariant
                             )
                         }
                     }
@@ -190,7 +190,7 @@ fun HomeScreen(
                                 modifier = Modifier
                                     .fillMaxWidth()
                                     .height(8.dp)
-                                    .background(Slate100.copy(alpha = 0.5f))
+                                    .background(MaterialTheme.colorScheme.surfaceVariant.copy(alpha = 0.5f))
                             )
                         }
 

android/app/src/main/java/com/memory/app/ui/screen/PostDetailScreen.kt

@@ -52,12 +52,12 @@ fun PostDetailScreen(
     Column(
         modifier = Modifier
             .fillMaxSize()
-            .background(Color.White)
+            .background(MaterialTheme.colorScheme.background)
     ) {
         // Header
         Surface(
             modifier = Modifier.fillMaxWidth(),
-            color = Color.White.copy(alpha = 0.95f)
+            color = MaterialTheme.colorScheme.surface.copy(alpha = 0.95f)
         ) {
             Row(
                 modifier = Modifier
@@ -71,7 +71,7 @@ fun PostDetailScreen(
                     Icon(
                         Icons.AutoMirrored.Filled.ArrowBack,
                         contentDescription = "返回",
-                        tint = Slate900,
+                        tint = MaterialTheme.colorScheme.onSurface,
                         modifier = Modifier.size(24.dp)
                     )
                 }
@@ -80,7 +80,7 @@ fun PostDetailScreen(
                     text = "帖子详情",
                     fontSize = 18.sp,
                     fontWeight = FontWeight.Bold,
-                    color = Slate900
+                    color = MaterialTheme.colorScheme.onSurface
                 )
                 Spacer(modifier = Modifier.weight(1f))
                 if (post?.userId == currentUserId) {
@@ -96,7 +96,7 @@ fun PostDetailScreen(
             }
         }
 
-        HorizontalDivider(color = Slate100, thickness = 1.dp)
+        HorizontalDivider(color = MaterialTheme.colorScheme.outlineVariant, thickness = 1.dp)
 
         // Content
         Box(modifier = Modifier.weight(1f)) {
@@ -121,7 +121,7 @@ fun PostDetailScreen(
                                     modifier = Modifier
                                         .size(48.dp)
                                         .clip(CircleShape)
-                                        .background(Slate100),
+                                        .background(MaterialTheme.colorScheme.surfaceVariant),
                                     contentAlignment = Alignment.Center
                                 ) {
                                     if (post.user?.avatarUrl?.isNotEmpty() == true) {
@@ -134,7 +134,7 @@ fun PostDetailScreen(
                                     } else {
                                         Text(
                                             text = post.user?.nickname?.firstOrNull()?.toString() ?: "?",
-                                            color = Slate600,
+                                            color = MaterialTheme.colorScheme.onSurfaceVariant,
                                             fontWeight = FontWeight.Bold,
                                             fontSize = 18.sp
                                         )
@@ -147,7 +147,7 @@ fun PostDetailScreen(
                                             text = post.user?.nickname ?: "",
                                             fontWeight = FontWeight.Bold,
                                             fontSize = 18.sp,
-                                            color = Slate900
+                                            color = MaterialTheme.colorScheme.onSurface
                                         )
                                         Spacer(modifier = Modifier.width(4.dp))
                                         Icon(
@@ -159,7 +159,7 @@ fun PostDetailScreen(
                                     }
                                     Text(
                                         text = "@${post.user?.username} · ${TimeUtils.formatRelative(post.createdAt)}",
-                                        color = Slate400,
+                                        color = MaterialTheme.colorScheme.onSurfaceVariant,
                                         fontSize = 14.sp
                                     )
                                 }
@@ -172,7 +172,7 @@ fun PostDetailScreen(
                                 text = post.content,
                                 fontSize = 15.sp,
                                 lineHeight = 22.sp,
-                                color = Slate800
+                                color = MaterialTheme.colorScheme.onSurface
                             )
 
                             // Media
@@ -204,12 +204,12 @@ fun PostDetailScreen(
                                         text = "${post.likeCount}",
                                         fontWeight = FontWeight.Bold,
                                         fontSize = 15.sp,
-                                        color = Slate900
+                                        color = MaterialTheme.colorScheme.onSurface
                                     )
                                     Text(
                                         text = " 获赞",
                                         fontSize = 15.sp,
-                                        color = Slate500
+                                        color = MaterialTheme.colorScheme.onSurfaceVariant
                                     )
                                 }
                                 Row(verticalAlignment = Alignment.CenterVertically) {
@@ -217,18 +217,18 @@ fun PostDetailScreen(
                                         text = "${comments.size}",
                                         fontWeight = FontWeight.Bold,
                                         fontSize = 15.sp,
-                                        color = Slate900
+                                        color = MaterialTheme.colorScheme.onSurface
                                     )
                                     Text(
                                         text = " 评论",
                                         fontSize = 15.sp,
-                                        color = Slate500
+                                        color = MaterialTheme.colorScheme.onSurfaceVariant
                                     )
                                 }
                             }
                         }
 
-                        HorizontalDivider(color = Slate50, thickness = 8.dp)
+                        HorizontalDivider(color = MaterialTheme.colorScheme.surfaceVariant, thickness = 8.dp)
                     }
 
                     // Comments
@@ -250,7 +250,7 @@ fun PostDetailScreen(
                             ) {
                                 Text(
                                     text = "还没有评论，快来抢沙发吧！",
-                                    color = Slate400,
+                                    color = MaterialTheme.colorScheme.onSurfaceVariant,
                                     fontSize = 14.sp
                                 )
                             }
@@ -263,9 +263,9 @@ fun PostDetailScreen(
         // Comment Input
         Surface(
             modifier = Modifier.fillMaxWidth(),
-            color = Color.White
+            color = MaterialTheme.colorScheme.surface
         ) {
-            HorizontalDivider(color = Slate100, thickness = 1.dp)
+            HorizontalDivider(color = MaterialTheme.colorScheme.outlineVariant, thickness = 1.dp)
             Row(
                 modifier = Modifier
                     .fillMaxWidth()
@@ -276,14 +276,14 @@ fun PostDetailScreen(
                 OutlinedTextField(
                     value = commentText,
                     onValueChange = { commentText = it },
-                    placeholder = { Text("写下你的评论...", color = Slate400, fontSize = 15.sp) },
+                    placeholder = { Text("写下你的评论...", color = MaterialTheme.colorScheme.onSurfaceVariant, fontSize = 15.sp) },
                     modifier = Modifier
                         .weight(1f)
                         .heightIn(min = 48.dp),
                     shape = RoundedCornerShape(24.dp),
                     colors = OutlinedTextFieldDefaults.colors(
-                        focusedContainerColor = Slate50,
-                        unfocusedContainerColor = Slate50,
+                        focusedContainerColor = MaterialTheme.colorScheme.surfaceVariant,
+                        unfocusedContainerColor = MaterialTheme.colorScheme.surfaceVariant,
                         focusedBorderColor = Color.Transparent,
                         unfocusedBorderColor = Color.Transparent
                     ),
@@ -293,7 +293,7 @@ fun PostDetailScreen(
                 Spacer(modifier = Modifier.width(12.dp))
                 Text(
                     text = "发送",
-                    color = if (commentText.isNotBlank()) Brand500 else Slate300,
+                    color = if (commentText.isNotBlank()) Brand500 else MaterialTheme.colorScheme.outlineVariant,
                     fontWeight = FontWeight.Bold,
                     fontSize = 15.sp,
                     modifier = Modifier
@@ -314,7 +314,7 @@ fun PostDetailScreen(
         Dialog(onDismissRequest = { showDeleteDialog = false }) {
             Surface(
                 shape = RoundedCornerShape(28.dp),
-                color = Color.White,
+                color = MaterialTheme.colorScheme.surface,
                 shadowElevation = 16.dp,
                 modifier = Modifier
                     .fillMaxWidth()
@@ -336,7 +336,7 @@ fun PostDetailScreen(
                             text = "删除帖子",
                             fontWeight = FontWeight.Bold,
                             fontSize = 20.sp,
-                            color = Slate900
+                            color = MaterialTheme.colorScheme.onSurface
                         )
                     }
 
@@ -346,7 +346,7 @@ fun PostDetailScreen(
                     Text(
                         text = "确定要删除这条帖子吗？此操作不可撤销。",
                         fontSize = 15.sp,
-                        color = Slate600,
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
                         lineHeight = 22.sp
                     )
 
@@ -363,7 +363,7 @@ fun PostDetailScreen(
                         ) {
                             Text(
                                 "取消",
-                                color = Slate500,
+                                color = MaterialTheme.colorScheme.onSurfaceVariant,
                                 fontSize = 15.sp,
                                 fontWeight = FontWeight.Medium
                             )
@@ -469,7 +469,7 @@ private fun CommentItem(
                 text = comment.user?.nickname ?: "",
                 fontWeight = FontWeight.Bold,
                 fontSize = 14.sp,
-                color = Slate900
+                color = MaterialTheme.colorScheme.onSurface
             )
             
             Spacer(modifier = Modifier.height(4.dp))
@@ -477,12 +477,12 @@ private fun CommentItem(
             // Comment bubble
             Surface(
                 shape = RoundedCornerShape(topStart = 4.dp, topEnd = 16.dp, bottomStart = 16.dp, bottomEnd = 16.dp),
-                color = Slate50
+                color = MaterialTheme.colorScheme.surfaceVariant
             ) {
                 Text(
                     text = comment.content,
                     fontSize = 14.sp,
-                    color = Slate700,
+                    color = MaterialTheme.colorScheme.onSurfaceVariant,
                     lineHeight = 20.sp,
                     modifier = Modifier.padding(12.dp)
                 )
@@ -497,12 +497,12 @@ private fun CommentItem(
                     text = "回复",
                     fontSize = 12.sp,
                     fontWeight = FontWeight.Bold,
-                    color = Slate400
+                    color = MaterialTheme.colorScheme.onSurfaceVariant
                 )
                 Text(
                     text = " · ${TimeUtils.formatRelative(comment.createdAt)}",
                     fontSize = 12.sp,
-                    color = Slate400
+                    color = MaterialTheme.colorScheme.onSurfaceVariant
                 )
             }
         }
@@ -516,7 +516,7 @@ private fun CommentItem(
                     Icons.Default.Delete,
                     contentDescription = "删除",
                     modifier = Modifier.size(16.dp),
-                    tint = Slate300
+                    tint = MaterialTheme.colorScheme.outline
                 )
             }
         }
@@ -526,7 +526,7 @@ private fun CommentItem(
         Dialog(onDismissRequest = { showDeleteDialog = false }) {
             Surface(
                 shape = RoundedCornerShape(28.dp),
-                color = Color.White,
+                color = MaterialTheme.colorScheme.surface,
                 shadowElevation = 16.dp,
                 modifier = Modifier
                     .fillMaxWidth()
@@ -547,7 +547,7 @@ private fun CommentItem(
                             text = "删除评论",
                             fontWeight = FontWeight.Bold,
                             fontSize = 20.sp,
-                            color = Slate900
+                            color = MaterialTheme.colorScheme.onSurface
                         )
                     }
 
@@ -556,7 +556,7 @@ private fun CommentItem(
                     Text(
                         text = "确定要删除这条评论吗？",
                         fontSize = 15.sp,
-                        color = Slate600
+                        color = MaterialTheme.colorScheme.onSurfaceVariant
                     )
 
                     Spacer(modifier = Modifier.height(24.dp))
@@ -571,7 +571,7 @@ private fun CommentItem(
                         ) {
                             Text(
                                 "取消",
-                                color = Slate500,
+                                color = MaterialTheme.colorScheme.onSurfaceVariant,
                                 fontSize = 15.sp,
                                 fontWeight = FontWeight.Medium
                             )

android/app/src/main/java/com/memory/app/ui/screen/ProfileScreen.kt

@@ -11,7 +11,9 @@ import androidx.compose.foundation.shape.CircleShape
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.icons.Icons
 import androidx.compose.material.icons.filled.CameraAlt
+import androidx.compose.material.icons.outlined.DarkMode
 import androidx.compose.material.icons.outlined.Edit
+import androidx.compose.material.icons.outlined.LightMode
 import androidx.compose.material3.*
 import androidx.compose.runtime.*
 import androidx.compose.ui.Alignment
@@ -34,10 +36,12 @@ fun ProfileScreen(
     postCount: Int,
     likeCount: Int,
     dayCount: Int = 1,
+    isDarkTheme: Boolean = false,
     onEditProfile: () -> Unit,
     onLogout: () -> Unit,
     onUpdateNickname: ((String) -> Unit)? = null,
-    onUpdateAvatar: ((Uri) -> Unit)? = null
+    onUpdateAvatar: ((Uri) -> Unit)? = null,
+    onToggleTheme: (() -> Unit)? = null
 ) {
     var isEditing by remember { mutableStateOf(false) }
     var editedNickname by remember(user) { mutableStateOf(user?.nickname ?: "") }
@@ -55,16 +59,43 @@ fun ProfileScreen(
     Column(
         modifier = Modifier
             .fillMaxSize()
-            .background(Color.White)
+            .background(MaterialTheme.colorScheme.background)
     ) {
-        // Header with logout button
+        // Header with theme toggle and logout button
         Row(
             modifier = Modifier
                 .fillMaxWidth()
                 .statusBarsPadding()
                 .padding(horizontal = 20.dp, vertical = 12.dp),
-            horizontalArrangement = Arrangement.End
+            horizontalArrangement = Arrangement.SpaceBetween,
+            verticalAlignment = Alignment.CenterVertically
         ) {
+            // Theme Toggle Button
+            Surface(
+                onClick = { onToggleTheme?.invoke() },
+                shape = RoundedCornerShape(50),
+                color = MaterialTheme.colorScheme.surfaceVariant
+            ) {
+                Row(
+                    modifier = Modifier.padding(horizontal = 12.dp, vertical = 8.dp),
+                    verticalAlignment = Alignment.CenterVertically
+                ) {
+                    Icon(
+                        imageVector = if (isDarkTheme) Icons.Outlined.DarkMode else Icons.Outlined.LightMode,
+                        contentDescription = "切换主题",
+                        modifier = Modifier.size(18.dp),
+                        tint = MaterialTheme.colorScheme.onSurfaceVariant
+                    )
+                    Spacer(modifier = Modifier.width(6.dp))
+                    Text(
+                        text = if (isDarkTheme) "深色" else "浅色",
+                        color = MaterialTheme.colorScheme.onSurfaceVariant,
+                        fontSize = 14.sp,
+                        fontWeight = FontWeight.Medium
+                    )
+                }
+            }
+            
             // Logout Button
             Surface(
                 onClick = onLogout,
@@ -97,8 +128,8 @@ fun ProfileScreen(
                     modifier = Modifier
                         .size(96.dp)
                         .clip(CircleShape)
-                        .background(Slate100)
-                        .border(1.dp, Slate100, CircleShape)
+                        .background(MaterialTheme.colorScheme.surfaceVariant)
+                        .border(1.dp, MaterialTheme.colorScheme.outline, CircleShape)
                         .clickable { imagePicker.launch("image/*") },
                     contentAlignment = Alignment.Center
                 ) {
@@ -124,7 +155,7 @@ fun ProfileScreen(
                                 text = user?.nickname?.firstOrNull()?.toString() ?: "?",
                                 fontSize = 36.sp,
                                 fontWeight = FontWeight.Bold,
-                                color = Slate600
+                                color = MaterialTheme.colorScheme.onSurfaceVariant
                             )
                         }
                     }
@@ -192,14 +223,14 @@ fun ProfileScreen(
                         text = user?.nickname ?: "",
                         fontSize = 24.sp,
                         fontWeight = FontWeight.Bold,
-                        color = Slate900
+                        color = MaterialTheme.colorScheme.onBackground
                     )
                     Spacer(modifier = Modifier.width(4.dp))
                     Icon(
                         Icons.Outlined.Edit,
                         contentDescription = "编辑昵称",
                         modifier = Modifier.size(16.dp),
-                        tint = Slate300
+                        tint = MaterialTheme.colorScheme.outline
                     )
                 }
             }
@@ -211,7 +242,7 @@ fun ProfileScreen(
                 text = "@${user?.username ?: ""}",
                 fontSize = 14.sp,
                 fontWeight = FontWeight.Medium,
-                color = Slate400
+                color = MaterialTheme.colorScheme.onSurfaceVariant
             )
 
             Spacer(modifier = Modifier.height(32.dp))
@@ -229,7 +260,7 @@ fun ProfileScreen(
             Spacer(modifier = Modifier.height(32.dp))
 
             // Divider
-            HorizontalDivider(color = Slate50, thickness = 1.dp)
+            HorizontalDivider(color = MaterialTheme.colorScheme.outlineVariant, thickness = 1.dp)
         }
     }
 }
@@ -247,14 +278,14 @@ private fun StatColumn(count: Int, label: String) {
             },
             fontSize = 24.sp,
             fontWeight = FontWeight.Bold,
-            color = Slate900
+            color = MaterialTheme.colorScheme.onBackground
         )
         Spacer(modifier = Modifier.height(4.dp))
         Text(
             text = label,
             fontSize = 12.sp,
             fontWeight = FontWeight.Bold,
-            color = Slate400,
+            color = MaterialTheme.colorScheme.onSurfaceVariant,
             letterSpacing = 0.5.sp
         )
     }

android/app/src/main/java/com/memory/app/ui/screen/SearchScreen.kt

@@ -57,14 +57,14 @@ fun SearchScreen(
     LazyColumn(
         modifier = Modifier
             .fillMaxSize()
-            .background(Color.White)
+            .background(MaterialTheme.colorScheme.background)
     ) {
         // Header
         item {
             Column(
                 modifier = Modifier
                     .fillMaxWidth()
-                    .background(Color.White)
+                    .background(MaterialTheme.colorScheme.background)
                     .statusBarsPadding()
                     .padding(horizontal = 20.dp, vertical = 16.dp)
             ) {
@@ -73,7 +73,7 @@ fun SearchScreen(
                     text = "搜索",
                     fontSize = 24.sp,
                     fontWeight = FontWeight.Bold,
-                    color = Slate900,
+                    color = MaterialTheme.colorScheme.onBackground,
                     modifier = Modifier.padding(bottom = 20.dp)
                 )
 
@@ -81,12 +81,12 @@ fun SearchScreen(
                 OutlinedTextField(
                     value = searchQuery,
                     onValueChange = { viewModel.updateQuery(it) },
-                    placeholder = { Text("搜索内容关键词...", color = Slate400, fontSize = 15.sp) },
+                    placeholder = { Text("搜索内容关键词...", color = MaterialTheme.colorScheme.onSurfaceVariant, fontSize = 15.sp) },
                     leadingIcon = {
                         Icon(
                             Icons.Outlined.Search,
                             contentDescription = null,
-                            tint = Slate400,
+                            tint = MaterialTheme.colorScheme.onSurfaceVariant,
                             modifier = Modifier.size(20.dp)
                         )
                     },
@@ -95,10 +95,10 @@ fun SearchScreen(
                         .shadow(2.dp, RoundedCornerShape(16.dp)),
                     shape = RoundedCornerShape(16.dp),
                     colors = OutlinedTextFieldDefaults.colors(
-                        focusedContainerColor = Slate50,
-                        unfocusedContainerColor = Slate50,
+                        focusedContainerColor = MaterialTheme.colorScheme.surfaceVariant,
+                        unfocusedContainerColor = MaterialTheme.colorScheme.surfaceVariant,
                         focusedBorderColor = Brand500,
-                        unfocusedBorderColor = Slate100,
+                        unfocusedBorderColor = MaterialTheme.colorScheme.outline,
                         cursorColor = Brand500
                     ),
                     singleLine = true
@@ -247,13 +247,13 @@ fun SearchScreen(
                             modifier = Modifier
                                 .size(64.dp)
                                 .clip(CircleShape)
-                                .background(Slate100),
+                                .background(MaterialTheme.colorScheme.surfaceVariant),
                             contentAlignment = Alignment.Center
                         ) {
                             Icon(
                                 Icons.Outlined.Search,
                                 contentDescription = null,
-                                tint = Slate400,
+                                tint = MaterialTheme.colorScheme.onSurfaceVariant,
                                 modifier = Modifier.size(32.dp)
                             )
                         }
@@ -261,12 +261,12 @@ fun SearchScreen(
                         Text(
                             text = "输入关键词或选择日期",
                             fontSize = 14.sp,
-                            color = Slate500
+                            color = MaterialTheme.colorScheme.onSurfaceVariant
                         )
                         Text(
                             text = "探索过去的足迹",
                             fontSize = 14.sp,
-                            color = Slate500
+                            color = MaterialTheme.colorScheme.onSurfaceVariant
                         )
                     }
                 }
@@ -280,7 +280,7 @@ fun SearchScreen(
                         onCommentClick = { onPostClick(post.id) },
                         onReactionClick = { }
                     )
-                    HorizontalDivider(color = Slate100, thickness = 1.dp)
+                    HorizontalDivider(color = MaterialTheme.colorScheme.outlineVariant, thickness = 1.dp)
                 }
                 // 底部留白
                 item {
@@ -333,7 +333,7 @@ private fun DatePickerDialog(
     androidx.compose.ui.window.Dialog(onDismissRequest = onDismiss) {
         Surface(
             shape = RoundedCornerShape(28.dp),
-            color = Color.White,
+            color = MaterialTheme.colorScheme.surface,
             shadowElevation = 16.dp,
             modifier = Modifier
                 .fillMaxWidth()
@@ -356,7 +356,7 @@ private fun DatePickerDialog(
                         text = "选择日期",
                         fontWeight = FontWeight.Bold,
                         fontSize = 20.sp,
-                        color = Slate900
+                        color = MaterialTheme.colorScheme.onSurface
                     )
                 }
 

android/app/src/main/java/com/memory/app/ui/theme/Theme.kt

@@ -3,6 +3,7 @@ package com.memory.app.ui.theme
 import android.app.Activity
 import androidx.compose.foundation.isSystemInDarkTheme
 import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.darkColorScheme
 import androidx.compose.material3.lightColorScheme
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.SideEffect
@@ -34,21 +35,45 @@ private val LightColorScheme = lightColorScheme(
     onError = Color.White
 )
 
+private val DarkColorScheme = darkColorScheme(
+    primary = Brand400,
+    onPrimary = Brand900,
+    primaryContainer = Brand700,
+    onPrimaryContainer = Brand100,
+    secondary = Slate300,
+    onSecondary = Slate900,
+    secondaryContainer = Slate700,
+    onSecondaryContainer = Slate100,
+    tertiary = Brand400,
+    onTertiary = Brand900,
+    background = Slate900,
+    onBackground = Slate100,
+    surface = Slate800,
+    onSurface = Slate100,
+    surfaceVariant = Slate700,
+    onSurfaceVariant = Slate300,
+    outline = Slate600,
+    outlineVariant = Slate700,
+    error = Color(0xFFFF6B6B),
+    onError = Color.White
+)
+
 @Composable
 fun MemoryTheme(
+    darkTheme: Boolean = isSystemInDarkTheme(),
     content: @Composable () -> Unit
 ) {
-    val colorScheme = LightColorScheme
+    val colorScheme = if (darkTheme) DarkColorScheme else LightColorScheme
     val view = LocalView.current
 
     if (!view.isInEditMode) {
         SideEffect {
             val window = (view.context as Activity).window
             window.statusBarColor = Color.Transparent.toArgb()
-            window.navigationBarColor = Color.White.toArgb()
+            window.navigationBarColor = if (darkTheme) Slate900.toArgb() else Color.White.toArgb()
             WindowCompat.getInsetsController(window, view).apply {
-                isAppearanceLightStatusBars = true
-                isAppearanceLightNavigationBars = true
+                isAppearanceLightStatusBars = !darkTheme
+                isAppearanceLightNavigationBars = !darkTheme
             }
         }
     }