diff --git a/lib/app/home_shell.dart b/lib/app/home_shell.dart
index 1696f32..934c102 100644
--- a/lib/app/home_shell.dart
+++ b/lib/app/home_shell.dart
@@ -28,11 +28,14 @@ class _HomeShellState extends State<HomeShell> {
     final l10n = AppLocalizations.of(context)!;
     return Scaffold(
       body: LiquidGlassView(
-        backgroundWidget: Image.asset(
-          AppConstants.wallpaperAsset,
-          fit: BoxFit.cover,
-          errorBuilder: (context, error, stackTrace) =>
-              const ColoredBox(color: Color(0xFF1A1A2E)),
+        backgroundWidget: Opacity(
+          opacity: AppConstants.wallpaperOpacity,
+          child: Image.asset(
+            AppConstants.wallpaperAsset,
+            fit: BoxFit.cover,
+            errorBuilder: (context, error, stackTrace) =>
+                const ColoredBox(color: Color(0xFF1A1A2E)),
+          ),
         ),
         realTimeCapture: false,
         child: Stack(
diff --git a/lib/core/constants/app_constants.dart b/lib/core/constants/app_constants.dart
index 879b2e9..4b16487 100644
--- a/lib/core/constants/app_constants.dart
+++ b/lib/core/constants/app_constants.dart
@@ -51,4 +51,10 @@ class AppConstants {
   /// `assets/images/` 配下の壁紙画像を指定する。変更時は `pubspec.yaml` の
   /// `flutter.assets` も合わせて更新すること。
   static const String wallpaperAsset = 'assets/images/wallpaper3.jpg';
+
+  /// 壁紙の不透明度 (0.0: 透明 〜 1.0: 不透明)。
+  ///
+  /// `HomeShell` の背景画像に適用される。値を下げると壁紙が薄くなり、
+  /// Liquid Glass の視認性が上がる。
+  static const double wallpaperOpacity = 1.0;
 }