diff --git a/open-isle-cli/src/components/MilkTeaActivityComponent.vue b/open-isle-cli/src/components/MilkTeaActivityComponent.vue
index 2fdae6fe0..bd9c4fffd 100644
--- a/open-isle-cli/src/components/MilkTeaActivityComponent.vue
+++ b/open-isle-cli/src/components/MilkTeaActivityComponent.vue
@@ -26,10 +26,10 @@
     <div v-if="dialogVisible" class="redeem-dialog">
       <div class="redeem-dialog-overlay" @click="closeDialog"></div>
       <div class="redeem-dialog-content">
-        <input v-model="contact" class="redeem-input" placeholder="联系方式" />
+        <BaseInput v-model="contact" placeholder="联系方式" />
         <div class="redeem-actions">
-          <button @click="submitRedeem" :disabled="loading">提交</button>
-          <button @click="closeDialog">取消</button>
+          <button class="redeem-submit-button" @click="submitRedeem" :disabled="loading">提交</button>
+          <button class="redeem-cancel-button" @click="closeDialog">取消</button>
         </div>
       </div>
     </div>
@@ -39,12 +39,13 @@
 <script>
 import ProgressBar from '../components/ProgressBar.vue'
 import LevelProgress from '../components/LevelProgress.vue'
+import BaseInput from './BaseInput.vue'
 import { API_BASE_URL, toast } from '../main'
 import { getToken, fetchCurrentUser } from '../utils/auth'
 
 export default {
   name: 'MilkTeaActivityComponent',
-  components: { ProgressBar, LevelProgress },
+  components: { ProgressBar, LevelProgress, BaseInput },
   data () {
     return {
       info: { level1Count: 0, ended: false },
@@ -189,6 +190,7 @@ export default {
   background-color: var(--background-color);
   padding: 20px;
   border-radius: 8px;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
   display: flex;
   flex-direction: column;
   gap: 10px;
@@ -202,9 +204,29 @@ export default {
   gap: 10px;
 }
 
-.redeem-input {
-  padding: 6px;
-  border: 1px solid var(--normal-border-color);
-  border-radius: 4px;
+.redeem-submit-button {
+  background-color: var(--primary-color);
+  color: #fff;
+  padding: 10px 20px;
+  border-radius: 10px;
+  cursor: pointer;
+}
+.redeem-submit-button:disabled {
+  background-color: var(--primary-color-disabled);
+  cursor: not-allowed;
+}
+.redeem-submit-button:hover {
+  background-color: var(--primary-color-hover);
+}
+.redeem-submit-button:disabled:hover {
+  background-color: var(--primary-color-disabled);
+}
+.redeem-cancel-button {
+  color: var(--primary-color);
+  border-radius: 10px;
+  cursor: pointer;
+}
+.redeem-cancel-button:hover {
+  text-decoration: underline;
 }
 </style>
diff --git a/src/main/java/com/openisle/service/ActivityService.java b/src/main/java/com/openisle/service/ActivityService.java
index 9ee87f891..d8cd41753 100644
--- a/src/main/java/com/openisle/service/ActivityService.java
+++ b/src/main/java/com/openisle/service/ActivityService.java
@@ -39,10 +39,7 @@ public class ActivityService {
 
     public void redeem(Activity activity, User user, String contact) {
         String content = user.getUsername() + " contact: " + contact;
-        for (User admin : userRepository.findByRole(Role.ADMIN)) {
-            notificationService.createNotification(admin, NotificationType.ACTIVITY_REDEEM,
-                    null, null, null, user, null, content);
-        }
+        notificationService.createActivityRedeemNotifications(user, content);
         activity.getParticipants().add(user);
         activityRepository.save(activity);
     }
diff --git a/src/main/java/com/openisle/service/NotificationService.java b/src/main/java/com/openisle/service/NotificationService.java
index efd9edf52..73ef61929 100644
--- a/src/main/java/com/openisle/service/NotificationService.java
+++ b/src/main/java/com/openisle/service/NotificationService.java
@@ -46,6 +46,19 @@ public class NotificationService {
         }
     }
 
+    /**
+     * Create notifications for all admins when a user redeems an activity.
+     * Old redeem notifications from the same user are removed first.
+     */
+    @org.springframework.transaction.annotation.Transactional
+    public void createActivityRedeemNotifications(User user, String content) {
+        notificationRepository.deleteByTypeAndFromUser(NotificationType.ACTIVITY_REDEEM, user);
+        for (User admin : userRepository.findByRole(Role.ADMIN)) {
+            createNotification(admin, NotificationType.ACTIVITY_REDEEM, null, null,
+                    null, user, null, content);
+        }
+    }
+
     public List<Notification> listNotifications(String username, Boolean read) {
         User user = userRepository.findByUsername(username)
                 .orElseThrow(() -> new com.openisle.exception.NotFoundException("User not found"));
diff --git a/src/test/java/com/openisle/service/NotificationServiceTest.java b/src/test/java/com/openisle/service/NotificationServiceTest.java
index 70d75301a..508915d32 100644
--- a/src/test/java/com/openisle/service/NotificationServiceTest.java
+++ b/src/test/java/com/openisle/service/NotificationServiceTest.java
@@ -96,4 +96,23 @@ class NotificationServiceTest {
         verify(nRepo).deleteByTypeAndFromUser(NotificationType.REGISTER_REQUEST, applicant);
         verify(nRepo).save(any(Notification.class));
     }
+
+    @Test
+    void createActivityRedeemNotificationsDeletesOldOnes() {
+        NotificationRepository nRepo = mock(NotificationRepository.class);
+        UserRepository uRepo = mock(UserRepository.class);
+        NotificationService service = new NotificationService(nRepo, uRepo);
+
+        User admin = new User();
+        admin.setId(10L);
+        User user = new User();
+        user.setId(20L);
+
+        when(uRepo.findByRole(Role.ADMIN)).thenReturn(List.of(admin));
+
+        service.createActivityRedeemNotifications(user, "contact");
+
+        verify(nRepo).deleteByTypeAndFromUser(NotificationType.ACTIVITY_REDEEM, user);
+        verify(nRepo).save(any(Notification.class));
+    }
 }