diff --git a/app/lib/core/theme/app_theme.dart b/app/lib/core/theme/app_theme.dart
index f2ceb66..0f36e8b 100644
--- a/app/lib/core/theme/app_theme.dart
+++ b/app/lib/core/theme/app_theme.dart
@@ -16,6 +16,14 @@ ThemeData buildAppTheme() {
     onPrimary: AppColors.onCosmicAccent,
     secondary: AppColors.neonViolet,
     onSecondary: AppColors.onNeonViolet,
+    // 컨테이너 슬롯을 비워 두면 Material 이 기본 시드(보라)에서 값을 만들어 낸다.
+    // ChoiceChip 의 선택 상태가 그 색을 쓰므로 코스믹 다크 위에 남색 칩이 뜬다.
+    primaryContainer: AppColors.cosmicSurfaceRaised,
+    onPrimaryContainer: AppColors.cosmicAccent,
+    secondaryContainer: AppColors.cosmicSurfaceRaised,
+    onSecondaryContainer: AppColors.cosmicAccent,
+    tertiaryContainer: AppColors.cosmicSurfaceRaised,
+    onTertiaryContainer: AppColors.neonCyan,
     tertiary: AppColors.neonCyan,
     onTertiary: AppColors.onNeonCyan,
     error: AppColors.error,
@@ -58,6 +66,110 @@ ThemeData buildAppTheme() {
       ),
     ),
     dividerTheme: const DividerThemeData(color: AppColors.cosmicOutline, thickness: 1),
+
+    // ── 아래는 테마를 주지 않으면 Material 3 기본값(보라 시드)으로 칠해지는 것들이다.
+    //    코스믹 다크 위에서 눈에 띄게 어긋나므로 전부 토큰으로 고정한다.
+    chipTheme: ChipThemeData(
+      backgroundColor: AppColors.cosmicSurfaceContainer,
+      selectedColor: AppColors.cosmicSurfaceRaised,
+      // 선택 상태는 색면이 아니라 테두리와 글자색으로 알린다 — 악센트는 행동에만 쓴다.
+      side: const BorderSide(color: AppColors.cosmicOutline),
+      shape: RoundedRectangleBorder(
+        borderRadius: BorderRadius.circular(AppRadius.full),
+      ),
+      labelStyle: _style(AppType.labelL, AppColors.onCosmicVariant),
+      secondaryLabelStyle: _style(AppType.labelL, AppColors.cosmicAccent),
+      checkmarkColor: AppColors.cosmicAccent,
+      showCheckmark: false,
+      padding: const EdgeInsets.symmetric(
+        horizontal: AppSpace.s3,
+        vertical: AppSpace.s2,
+      ),
+    ),
+    cardTheme: CardThemeData(
+      color: AppColors.cosmicSurfaceContainer,
+      surfaceTintColor: Colors.transparent,
+      elevation: 0,
+      margin: EdgeInsets.zero,
+      shape: RoundedRectangleBorder(
+        borderRadius: BorderRadius.circular(AppRadius.md),
+      ),
+    ),
+    floatingActionButtonTheme: FloatingActionButtonThemeData(
+      backgroundColor: AppColors.cosmicAccent,
+      foregroundColor: AppColors.onCosmicAccent,
+      elevation: 0,
+      extendedTextStyle: _styleNoColor(AppType.titleM),
+      shape: RoundedRectangleBorder(
+        borderRadius: BorderRadius.circular(AppRadius.full),
+      ),
+    ),
+    inputDecorationTheme: InputDecorationTheme(
+      // 채워진 상자 대신 밑줄을 쓴다. 어두운 서피스에서 상자를 겹치면 층이 흐려진다.
+      labelStyle: _style(AppType.bodyM, AppColors.onCosmicVariant),
+      floatingLabelStyle: _style(AppType.caption, AppColors.cosmicAccent),
+      helperStyle: _style(AppType.caption, AppColors.onCosmicVariant),
+      counterStyle: _style(AppType.caption, AppColors.onCosmicVariant),
+      enabledBorder: const UnderlineInputBorder(
+        borderSide: BorderSide(color: AppColors.cosmicOutline),
+      ),
+      focusedBorder: const UnderlineInputBorder(
+        borderSide: BorderSide(color: AppColors.cosmicAccent, width: 2),
+      ),
+      errorBorder: const UnderlineInputBorder(
+        borderSide: BorderSide(color: AppColors.error),
+      ),
+    ),
+    progressIndicatorTheme: const ProgressIndicatorThemeData(
+      color: AppColors.cosmicAccent,
+      linearTrackColor: AppColors.cosmicSurfaceRaised,
+      circularTrackColor: Colors.transparent,
+    ),
+    bottomSheetTheme: BottomSheetThemeData(
+      backgroundColor: AppColors.cosmicSurfaceContainer,
+      surfaceTintColor: Colors.transparent,
+      shape: RoundedRectangleBorder(
+        borderRadius: BorderRadius.vertical(top: Radius.circular(AppRadius.lg)),
+      ),
+    ),
+    dialogTheme: DialogThemeData(
+      backgroundColor: AppColors.cosmicSurfaceContainer,
+      surfaceTintColor: Colors.transparent,
+      shape: RoundedRectangleBorder(
+        borderRadius: BorderRadius.circular(AppRadius.lg),
+      ),
+    ),
+    snackBarTheme: SnackBarThemeData(
+      backgroundColor: AppColors.cosmicSurfaceRaised,
+      contentTextStyle: _style(AppType.bodyM, AppColors.onCosmic),
+      behavior: SnackBarBehavior.floating,
+      shape: RoundedRectangleBorder(
+        borderRadius: BorderRadius.circular(AppRadius.md),
+      ),
+    ),
+    listTileTheme: ListTileThemeData(
+      iconColor: AppColors.onCosmicVariant,
+      titleTextStyle: _style(AppType.bodyL, AppColors.onCosmic),
+      subtitleTextStyle: _style(AppType.bodyS, AppColors.onCosmicVariant),
+    ),
+    textButtonTheme: TextButtonThemeData(
+      style: TextButton.styleFrom(
+        foregroundColor: AppColors.cosmicAccent,
+        textStyle: _styleNoColor(AppType.titleM),
+      ),
+    ),
+    outlinedButtonTheme: OutlinedButtonThemeData(
+      style: OutlinedButton.styleFrom(
+        foregroundColor: AppColors.onCosmic,
+        side: const BorderSide(color: AppColors.cosmicOutline),
+        minimumSize: const Size.fromHeight(AppSizing.touchMinApp),
+        shape: RoundedRectangleBorder(
+          borderRadius: BorderRadius.circular(AppRadius.md),
+        ),
+        textStyle: _styleNoColor(AppType.titleM),
+      ),
+    ),
+    iconTheme: const IconThemeData(color: AppColors.onCosmicVariant),
     filledButtonTheme: FilledButtonThemeData(
       style: FilledButton.styleFrom(
         minimumSize: const Size.fromHeight(AppSizing.touchMinApp),
diff --git a/app/test/theme_coverage_test.dart b/app/test/theme_coverage_test.dart
new file mode 100644
index 0000000..1c3b46c
--- /dev/null
+++ b/app/test/theme_coverage_test.dart
@@ -0,0 +1,68 @@
+import 'package:fancake/core/theme/app_theme.dart';
+import 'package:fancake/core/theme/tokens.dart';
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+/// 테마를 주지 않은 컴포넌트는 Material 3 가 기본 시드(보라)에서 색을 만들어 낸다.
+///
+/// 코스믹 다크 서피스 위에 그 색이 뜨면 시안과 어긋나는데, 화면을 눈으로 보기
+/// 전까지 드러나지 않는다. 실제로 INSIDE·STATION 정렬 칩이 보라색으로 나간 적이
+/// 있어(09-02) 그 회귀를 여기서 잡는다.
+void main() {
+  final theme = buildAppTheme();
+
+  /// 코스믹 팔레트에 속한 색인가. 토큰 밖의 색이면 Material 이 만들어 낸 것이다.
+  bool isCosmic(Color? c) {
+    if (c == null) return false;
+    final palette = <Color>{
+      AppColors.cosmicVoid,
+      AppColors.cosmicSurface,
+      AppColors.cosmicSurfaceContainer,
+      AppColors.cosmicSurfaceRaised,
+      AppColors.cosmicOutline,
+      AppColors.cosmicAccent,
+      AppColors.onCosmic,
+      AppColors.onCosmicVariant,
+      AppColors.onCosmicAccent,
+      AppColors.neonCyan,
+      AppColors.neonViolet,
+      AppColors.error,
+    };
+    return palette.contains(c) || c == Colors.transparent;
+  }
+
+  group('테마가 컴포넌트를 비워 두지 않는다', () {
+    test('Material 기본값으로 떨어지던 12종에 테마가 있다', () {
+      expect(theme.chipTheme.backgroundColor, isNotNull, reason: 'ChipTheme');
+      expect(theme.cardTheme.color, isNotNull, reason: 'CardTheme');
+      expect(theme.floatingActionButtonTheme.backgroundColor, isNotNull, reason: 'FAB');
+      expect(theme.inputDecorationTheme.focusedBorder, isNotNull, reason: 'Input');
+      expect(theme.progressIndicatorTheme.color, isNotNull, reason: 'Progress');
+      expect(theme.bottomSheetTheme.backgroundColor, isNotNull, reason: 'BottomSheet');
+      expect(theme.dialogTheme.backgroundColor, isNotNull, reason: 'Dialog');
+      expect(theme.snackBarTheme.backgroundColor, isNotNull, reason: 'SnackBar');
+      expect(theme.listTileTheme.titleTextStyle, isNotNull, reason: 'ListTile');
+      expect(theme.textButtonTheme.style, isNotNull, reason: 'TextButton');
+      expect(theme.outlinedButtonTheme.style, isNotNull, reason: 'OutlinedButton');
+      expect(theme.iconTheme.color, isNotNull, reason: 'IconTheme');
+    });
+
+    test('칩 색이 코스믹 팔레트 안에 있다', () {
+      // 보라색 칩이 다시 나오면 여기서 잡힌다.
+      expect(isCosmic(theme.chipTheme.backgroundColor), isTrue);
+      expect(isCosmic(theme.chipTheme.selectedColor), isTrue);
+    });
+
+    test('ColorScheme 의 컨테이너 슬롯이 채워져 있다', () {
+      // 비워 두면 Material 이 시드에서 만들어 내고, 그 값이 칩·배지로 샌다.
+      final s = theme.colorScheme;
+      for (final (name, c) in [
+        ('primaryContainer', s.primaryContainer),
+        ('secondaryContainer', s.secondaryContainer),
+        ('tertiaryContainer', s.tertiaryContainer),
+      ]) {
+        expect(isCosmic(c), isTrue, reason: '$name 이 팔레트 밖이다: $c');
+      }
+    });
+  });
+}