diff --git a/app/src/main/java/com/example/login_v3/navigation/Main_Screen_tab.kt b/app/src/main/java/com/example/login_v3/navigation/Main_Screen_tab.kt
index 46c6cc7..717eae8 100644
--- a/app/src/main/java/com/example/login_v3/navigation/Main_Screen_tab.kt
+++ b/app/src/main/java/com/example/login_v3/navigation/Main_Screen_tab.kt
@@ -22,62 +22,62 @@ import androidx.compose.ui.graphics.Color
 import androidx.compose.ui.graphics.graphicsLayer
 import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.dp
+import androidx.hilt.navigation.compose.hiltViewModel
 import com.example.login_v3.home.Tg_MarketPlace
 import com.example.login_v3.home.Message.UI.Tg_Message
 import com.example.login_v3.home.Tg_Server
 import com.example.login_v3.home.setting.Tg_Setting
 import androidx.lifecycle.viewmodel.compose.viewModel
+import com.example.login_v3.home.setting.setting_detail_page.viewmodel.Theme_ViewModel
 
 
+import androidx.hilt.navigation.compose.hiltViewModel // 確保有引入 hiltViewModel
+import com.example.login_v3.navigation.components.AppWallpaperBackground
 
 @Composable
-fun MainScreen_tab() {
-
+fun MainScreen_tab(
+    // 注入 Theme_ViewModel 來讀取壁紙狀態
+    themeViewModel: Theme_ViewModel = hiltViewModel()
+) {
     val screensViewModel: ScreensViewModel = viewModel()
     val bottomBarViewModel: BottomBarViewModel = viewModel()
 
-    //show bottom bar or not
+    // show bottom bar or not
     val showBottomBar by bottomBarViewModel.showBottomBar.collectAsState()
     val navHeight = 64.dp
     val gap = 40.dp
     val bottomBarHeight = navHeight + gap
 
-    Scaffold(
-        containerColor = Color.Transparent,
-        modifier = Modifier
-            .fillMaxSize()
-            .background(brush = Brush.verticalGradient(
-                colors = listOf(
-                    Color(0xFFDA7029),
-                    Color(0xFF777777),
-                    Color(0xFFB34800)
-                )
-            )),
-
-        bottomBar = {
-            BottomBarAnimated(
-                visible = showBottomBar,
-                height = bottomBarHeight,
-                content = {
-                    Column(modifier = Modifier.fillMaxWidth()) {
-                        Box(
-                            modifier = Modifier
-                                .fillMaxWidth()
-                                .height(navHeight)
-                        ) {
-                            nav_Wheel_display_block(screensViewModel = screensViewModel)
+    // 使用剛剛做好的壁紙元件包在最外層
+    AppWallpaperBackground(viewModel = themeViewModel) {
+        Scaffold(
+            containerColor = Color.Transparent, // 必須保持透明，底層的壁紙才看得到
+            modifier = Modifier.fillMaxSize(),
+            bottomBar = {
+                BottomBarAnimated(
+                    visible = showBottomBar,
+                    height = bottomBarHeight,
+                    content = {
+                        Column(modifier = Modifier.fillMaxWidth()) {
+                            Box(
+                                modifier = Modifier
+                                    .fillMaxWidth()
+                                    .height(navHeight)
+                            ) {
+                                nav_Wheel_display_block(screensViewModel = screensViewModel)
+                            }
+                            Spacer(modifier = Modifier.height(gap))
                         }
-                        Spacer(modifier = Modifier.height(gap)) // 真正的底下空白
                     }
-                }
+                )
+            }
+        ) { innerPadding ->
+            Screens_NavGraph(
+                paddingValues = innerPadding,
+                screensViewModel = screensViewModel,
+                bottomBarViewModel = bottomBarViewModel
             )
         }
-    ) { innerPadding ->
-        Screens_NavGraph(
-            paddingValues = innerPadding,
-            screensViewModel = screensViewModel,
-            bottomBarViewModel = bottomBarViewModel
-        )
     }
 }
 
diff --git a/app/src/main/java/com/example/login_v3/navigation/components/App_Wallpaper_Background.kt b/app/src/main/java/com/example/login_v3/navigation/components/App_Wallpaper_Background.kt
new file mode 100644
index 0000000..1e18bbc
--- /dev/null
+++ b/app/src/main/java/com/example/login_v3/navigation/components/App_Wallpaper_Background.kt
@@ -0,0 +1,59 @@
+package com.example.login_v3.navigation.components
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.collectAsState
+import androidx.compose.runtime.getValue
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Brush
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.layout.ContentScale
+import coil.compose.AsyncImage
+import com.example.login_v3.home.setting.setting_detail_page.viewmodel.Theme_ViewModel
+import java.io.File
+
+@Composable
+fun AppWallpaperBackground(
+    viewModel: Theme_ViewModel,
+    modifier: Modifier = Modifier,
+    content: @Composable () -> Unit
+) {
+    // 監聽來自 DataStore 的壁紙路徑
+    val wallpaperPath by viewModel.customWallpaperPath.collectAsState()
+
+    // 檢查檔案是否真的存在
+    val wallpaperFile = wallpaperPath?.let { File(it) }
+    val hasCustomWallpaper = wallpaperFile != null && wallpaperFile.exists()
+
+    Box(modifier = modifier.fillMaxSize()) {
+        if (hasCustomWallpaper) {
+            // 1. 如果有自訂壁紙，使用 Coil 填滿背景
+            AsyncImage(
+                model = wallpaperFile,
+                contentDescription = "App Custom Wallpaper",
+                modifier = Modifier.fillMaxSize(),
+                contentScale = ContentScale.Crop // 裁切填滿
+            )
+        } else {
+            // 2. 如果沒有，使用你原本的三色漸層
+            Box(
+                modifier = Modifier
+                    .fillMaxSize()
+                    .background(
+                        brush = Brush.verticalGradient(
+                            colors = listOf(
+                                Color(0xFFDA7029),
+                                Color(0xFF777777),
+                                Color(0xFFB34800)
+                            )
+                        )
+                    )
+            )
+        }
+
+        // 3. 將原本的 Scaffold 或內容蓋在背景上方
+        content()
+    }
+}
\ No newline at end of file