diff --git a/lib/src/screens/browse_screen.dart b/lib/src/screens/browse_screen.dart
index a36ae9d..909bb2f 100644
--- a/lib/src/screens/browse_screen.dart
+++ b/lib/src/screens/browse_screen.dart
@@ -530,13 +530,21 @@ class _BrowseScreenState extends State<BrowseScreen> with SingleTickerProviderSt
           onPressed: _deleteSelected,
         ),
         IconButton(
-          icon: const Icon(Icons.timer_off),
+          icon: Icon(_toggleIntervalIcon),
           onPressed: _toggleIntervalForSelected,
         ),
       ],
     );
   }
 
+  IconData get _toggleIntervalIcon {
+    if (_selectedItems.isEmpty) {
+      return Icons.timer_off;
+    }
+    final bool willEnable = _selectedItems.any((item) => !item.useInterval);
+    return willEnable ? Icons.timer : Icons.timer_off;
+  }
+
   void _selectAll() {
     setState(() {
       if (_selectedItems.length == _customDeck.length) {
@@ -577,23 +585,40 @@ class _BrowseScreenState extends State<BrowseScreen> with SingleTickerProviderSt
     );
   }
 
-  void _toggleIntervalForSelected() {
+  Future<void> _toggleIntervalForSelected() async {
+    if (_selectedItems.isEmpty) {
+      return;
+    }
+    final bool targetState = _selectedItems.any((item) => !item.useInterval);
+
+    final selectedCharacters = _selectedItems.map((item) => item.characters).toSet();
+
+    final List<CustomKanjiItem> updatedItems = [];
     for (final item in _selectedItems) {
       final updatedItem = CustomKanjiItem(
         characters: item.characters,
         meaning: item.meaning,
         kanji: item.kanji,
-        useInterval: !item.useInterval,
+        useInterval: targetState,
         srsLevel: item.srsLevel,
         nextReview: item.nextReview,
       );
-      _customDeckRepository.updateCard(updatedItem);
+      updatedItems.add(updatedItem);
     }
+
+    await _customDeckRepository.updateCards(updatedItems);
+    await _loadCustomDeck();
+
+    final newSelectedItems = _customDeck
+        .where((item) => selectedCharacters.contains(item.characters))
+        .toList();
+
     setState(() {
-      _isSelectionMode = false;
-      _selectedItems.clear();
+      _selectedItems = newSelectedItems;
+      if (_selectedItems.isEmpty) {
+        _isSelectionMode = false;
+      }
     });
-    _loadCustomDeck();
   }
 
   Widget _buildCustomGridView(List<CustomKanjiItem> items) {
@@ -639,35 +664,53 @@ class _BrowseScreenState extends State<BrowseScreen> with SingleTickerProviderSt
             }
           },
           child: Card(
+            shape: RoundedRectangleBorder(
+              side: isSelected
+                  ? const BorderSide(color: Colors.blue, width: 2.0)
+                  : BorderSide.none,
+              borderRadius: BorderRadius.circular(12.0),
+            ),
             color: isSelected
                 ? Colors.blue.withOpacity(0.5)
-                : item.useInterval
-                    ? Color.lerp(const Color(0xFF1E1E1E), Colors.blue, 0.1)
-                    : const Color(0xFF1E1E1E),
-            child: Padding(
-              padding: const EdgeInsets.all(8.0),
-              child: Column(
-                mainAxisAlignment: MainAxisAlignment.center,
-                children: [
-                  FittedBox(
-                    fit: BoxFit.scaleDown,
-                    child: Text(
-                      item.kanji ?? item.characters,
-                      style: const TextStyle(fontSize: 32, color: Colors.white),
-                      textAlign: TextAlign.center,
+                : const Color(0xFF1E1E1E),
+            child: Stack(
+              children: [
+                Padding(
+                  padding: const EdgeInsets.all(8.0),
+                  child: Column(
+                    mainAxisAlignment: MainAxisAlignment.center,
+                    children: [
+                      FittedBox(
+                        fit: BoxFit.scaleDown,
+                        child: Text(
+                          item.kanji ?? item.characters,
+                          style: const TextStyle(fontSize: 32, color: Colors.white),
+                          textAlign: TextAlign.center,
+                        ),
+                      ),
+                      const SizedBox(height: 8),
+                      Text(
+                        item.meaning,
+                        style: const TextStyle(color: Colors.grey, fontSize: 16),
+                        textAlign: TextAlign.center,
+                        overflow: TextOverflow.ellipsis,
+                      ),
+                      const SizedBox(height: 8),
+                      _buildSrsIndicator(item.srsLevel),
+                    ],
+                  ),
+                ),
+                if (item.useInterval)
+                  Positioned(
+                    top: 4,
+                    right: 4,
+                    child: Icon(
+                      Icons.timer,
+                      color: Colors.green,
+                      size: 16,
                     ),
                   ),
-                  const SizedBox(height: 8),
-                  Text(
-                    item.meaning,
-                    style: const TextStyle(color: Colors.grey, fontSize: 16),
-                    textAlign: TextAlign.center,
-                    overflow: TextOverflow.ellipsis,
-                  ),
-                  const SizedBox(height: 8),
-                  _buildSrsIndicator(item.srsLevel),
-                ],
-              ),
+              ],
             ),
           ),
         );
@@ -675,6 +718,4 @@ class _BrowseScreenState extends State<BrowseScreen> with SingleTickerProviderSt
       padding: const EdgeInsets.all(8),
     );
   }
-
-
-}
\ No newline at end of file
+}
diff --git a/lib/src/services/custom_deck_repository.dart b/lib/src/services/custom_deck_repository.dart
index a1f9723..0e21da4 100644
--- a/lib/src/services/custom_deck_repository.dart
+++ b/lib/src/services/custom_deck_repository.dart
@@ -31,6 +31,17 @@ class CustomDeckRepository {
     }
   }
 
+  Future<void> updateCards(List<CustomKanjiItem> itemsToUpdate) async {
+    final deck = await getCustomDeck();
+    for (var item in itemsToUpdate) {
+      final index = deck.indexWhere((element) => element.characters == item.characters);
+      if (index != -1) {
+        deck[index] = item;
+      }
+    }
+    await saveDeck(deck);
+  }
+
   Future<void> deleteCard(CustomKanjiItem item) async {
     final deck = await getCustomDeck();
     deck.removeWhere((element) => element.characters == item.characters);