fix(home): 首页深色底部导航补齐安全区底色

lib/core/widgets/app_bottom_nav.dart

@@ -43,37 +43,35 @@ class AppBottomNav extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
+    final bar = Container(
+      key: barKey,
+      height: AppDimens.navHeight,
+      decoration: BoxDecoration(
+        color: dark ? Colors.black : backgroundColor.withValues(alpha: 0.95),
+        border: Border(
+          top: BorderSide(color: dark ? Colors.white12 : AppColors.border),
+        ),
+      ),
+      child: Row(
+        children: [
+          for (final item in items)
+            _NavDestination(
+              item: item,
+              unselectedColor: dark ? Colors.white70 : AppColors.navUnselected,
+            ),
+        ],
+      ),
+    );
+    if (dark) {
+      return ColoredBox(
+        color: Colors.black,
+        child: SafeArea(top: false, child: bar),
+      );
+    }
     return ClipRect(
       child: BackdropFilter(
         filter: ImageFilter.blur(sigmaX: 20, sigmaY: 20),
-        child: SafeArea(
+        child: SafeArea(top: false, child: bar),
-          top: false,
-          child: Container(
-            key: barKey,
-            height: AppDimens.navHeight,
-            decoration: BoxDecoration(
-              color: dark
-                  ? const Color(0xE6000000)
-                  : backgroundColor.withValues(alpha: 0.95),
-              border: Border(
-                top: BorderSide(
-                  color: dark ? Colors.white12 : AppColors.border,
-                ),
-              ),
-            ),
-            child: Row(
-              children: [
-                for (final item in items)
-                  _NavDestination(
-                    item: item,
-                    unselectedColor: dark
-                        ? Colors.white70
-                        : AppColors.navUnselected,
-                  ),
-              ],
-            ),
-          ),
-        ),
       ),
     );
   }

test/home/app_bottom_nav_test.dart

@@ -82,4 +82,68 @@ void main() {
     await tester.tap(find.byKey(const Key('tab-theater')));
     expect(theaterTaps, 1);
   });
+
+  testWidgets('should_fill_dark_bottom_safe_area_with_black_background', (
+    tester,
+  ) async {
+    const barKey = Key('dark-nav-bar');
+    await tester.pumpWidget(
+      MaterialApp(
+        home: MediaQuery(
+          data: const MediaQueryData(padding: EdgeInsets.only(bottom: 34)),
+          child: Scaffold(
+            bottomNavigationBar: AppBottomNav(
+              dark: true,
+              barKey: barKey,
+              items: [
+                AppBottomNavItem(
+                  tabKey: const Key('tab-home'),
+                  icon: Icons.movie_outlined,
+                  selectedIcon: Icons.movie_rounded,
+                  label: 'Home',
+                  selected: true,
+                  onTap: () {},
+                ),
+                AppBottomNavItem(
+                  tabKey: const Key('tab-theater'),
+                  icon: Icons.explore_outlined,
+                  selectedIcon: Icons.explore_rounded,
+                  label: 'Theater',
+                  onTap: () {},
+                ),
+                AppBottomNavItem(
+                  tabKey: const Key('tab-create'),
+                  icon: Icons.add_box_outlined,
+                  selectedIcon: Icons.add_box_rounded,
+                  label: 'Create',
+                  onTap: () {},
+                ),
+                AppBottomNavItem(
+                  tabKey: const Key('tab-mine'),
+                  icon: Icons.person_outline_rounded,
+                  selectedIcon: Icons.person_rounded,
+                  label: 'Me',
+                  onTap: () {},
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+
+    expect(
+      tester.getSize(find.byType(AppBottomNav)).height,
+      AppDimens.navHeight + 34,
+    );
+    expect(tester.getSize(find.byKey(barKey)).height, AppDimens.navHeight);
+
+    final coloredBox = tester.widget<ColoredBox>(
+      find.descendant(
+        of: find.byType(AppBottomNav),
+        matching: find.byType(ColoredBox),
+      ),
+    );
+    expect(coloredBox.color, Colors.black);
+  });
 }

test/home/home_nav_ui_test.dart

@@ -53,7 +53,7 @@ void main() {
     final decoration = bar.decoration as BoxDecoration;
     final border = decoration.border as Border;
     // 首页 feed 用深色导航。
-    expect(decoration.color, const Color(0xE6000000));
+    expect(decoration.color, Colors.black);
     expect(border.top.color, Colors.white12);
     expect(
       tester