diff --git a/app/src/main/java/com/example/login_v3/data/di/DataStoreModule.kt b/app/src/main/java/com/example/login_v3/data/di/DataStoreModule.kt
new file mode 100644
index 0000000..90c9cb2
--- /dev/null
+++ b/app/src/main/java/com/example/login_v3/data/di/DataStoreModule.kt
@@ -0,0 +1,31 @@
+package com.example.login_v3.data.di
+
+import android.content.Context
+import androidx.datastore.core.DataStore
+// 修正 1: 確保匯入的是 androidx 的 Preferences
+import androidx.datastore.preferences.core.Preferences
+import androidx.datastore.preferences.preferencesDataStore
+import com.example.login_v3.data.local.UserPreferences.UserPreferencesRepository
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.android.qualifiers.ApplicationContext
+import dagger.hilt.components.SingletonComponent
+import javax.inject.Singleton
+
+// 定義擴充屬性，這裡保持為檔案私有 (private) 是沒問題的
+private val Context.dataStore: DataStore<Preferences> by preferencesDataStore(name = "user_prefs")
+
+@Module
+@InstallIn(SingletonComponent::class)
+// 修正 2: 移除 private，讓 Hilt 可以訪問這個模組
+object DataStoreModule {
+
+    @Provides
+    @Singleton
+    fun provideUserPreferencesRepository(
+        @ApplicationContext context: Context
+    ): UserPreferencesRepository {
+        return UserPreferencesRepository(context.dataStore)
+    }
+}
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diff --git a/app/src/main/java/com/example/login_v3/home/setting/setting_detail_page/viewmodel/Theme_ViewModel.kt b/app/src/main/java/com/example/login_v3/home/setting/setting_detail_page/viewmodel/Theme_ViewModel.kt
index 22d455e..b6b0e41 100644
--- a/app/src/main/java/com/example/login_v3/home/setting/setting_detail_page/viewmodel/Theme_ViewModel.kt
+++ b/app/src/main/java/com/example/login_v3/home/setting/setting_detail_page/viewmodel/Theme_ViewModel.kt
@@ -1,21 +1,43 @@
 package com.example.login_v3.home.setting.setting_detail_page.viewmodel
 
 import android.util.Log
-import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.setValue
 import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import com.example.login_v3.data.local.UserPreferences.UserPreferencesRepository
 import com.example.login_v3.ui.theme.AppTheme
-import kotlinx.coroutines.flow.MutableStateFlow
+import dagger.hilt.android.lifecycle.HiltViewModel
+import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
-import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.launch
+import javax.inject.Inject
 
-class Theme_ViewModel : ViewModel() {
-    private val _currentTheme = MutableStateFlow(AppTheme.DARK)
-    val currentTheme: StateFlow<AppTheme> = _currentTheme.asStateFlow()
+@HiltViewModel // 1. 加上 Hilt 註解
+class Theme_ViewModel @Inject constructor(
+    private val repository: UserPreferencesRepository // 2. 注入 Repository
+) : ViewModel() {
 
+    // 3. 讀取：將 repository 的 Flow 映射為 AppTheme，並轉為 StateFlow
+    val currentTheme: StateFlow<AppTheme> = repository.themeModeFlow
+        .map { themeName ->
+            try {
+                AppTheme.valueOf(themeName.uppercase()) // 假設 AppTheme 是 Enum
+            } catch (e: Exception) {
+                AppTheme.DARK // 轉換失敗時的預設值
+            }
+        }
+        .stateIn(
+            scope = viewModelScope,
+            started = SharingStarted.WhileSubscribed(5000),
+            initialValue = AppTheme.DARK // 初始值
+        )
+
+    // 4. 更新：除了更新狀態，還要存入 DataStore
     fun updateTheme(newTheme: AppTheme) {
-        Log.d("ThemeDebug", "ViewModel 更新主題為: $newTheme")
-        _currentTheme.value = newTheme
+        Log.d("ThemeDebug", "ViewModel 更新主題並儲存至 DataStore: $newTheme")
+        viewModelScope.launch {
+            repository.saveThemeMode(newTheme.name) // 儲存 Enum 的名稱 (例如 "DARK")
+        }
     }
 }
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