diff --git a/app-ios/Native/Sources/Root/RootScreen.swift b/app-ios/Native/Sources/Root/RootScreen.swift
index f38ce830f..e0bcf4295 100644
--- a/app-ios/Native/Sources/Root/RootScreen.swift
+++ b/app-ios/Native/Sources/Root/RootScreen.swift
@@ -50,10 +50,13 @@ public struct RootScreen: View {
     @State private var composeMultiplatformEnabled = false
     @State private var favoriteScreenUiMode: FavoriteScreenUiModePicker.UiMode = .swiftui
     private let presenter = RootPresenter()
+
     @State private var notificationCoordinator: NotificationNavigationCoordinator?
     @Dependency(\.notificationUseCase) private var notificationUseCase
     @Dependency(\.timetableUseCase) private var timetableUseCase
 
+    @State private var notificationCoordinator: NotificationNavigationCoordinator?
+
     public init() {
         UITabBar.appearance().unselectedItemTintColor = UIColor(named: "tab_inactive")
     }
@@ -396,15 +399,41 @@ public struct RootScreen: View {
                 }
             }
             .frame(width: geometry.size.width, height: geometry.size.height)
+            .padding(.horizontal, 12)
+            .modifier(TabBarBackground())
         }
         .frame(height: 64)
         .frame(maxWidth: .infinity)
-        .padding(.horizontal, 12)
-        .background(.ultraThinMaterial, in: Capsule())
-        .overlay(Capsule().stroke(AssetColors.outline.swiftUIColor, lineWidth: 1))
         .environment(\.colorScheme, .dark)
         .padding(.horizontal, 48)
     }
+
+    /// 背景用のカスタム Modifier
+    private struct TabBarBackground: ViewModifier {
+        @Environment(\.accessibilityReduceTransparency) private var reduceTransparency
+
+        func body(content: Content) -> some View {
+            if reduceTransparency {
+                // 透明度を下げる設定が有効 → 単色背景
+                content
+                    .background(AssetColors.surface.swiftUIColor, in: Capsule())
+                    .overlay(
+                        Capsule().stroke(AssetColors.outline.swiftUIColor, lineWidth: 1)
+                    )
+            } else {
+                if #available(iOS 26.0, *) {
+                    content
+                        .glassEffect(in: Capsule())
+                } else {
+                    content
+                        .background(.ultraThinMaterial, in: Capsule())
+                        .overlay(
+                            Capsule().stroke(AssetColors.outline.swiftUIColor, lineWidth: 1)
+                        )
+                }
+            }
+        }
+    }
 }
 
 #Preview {