diff --git a/src/frontend/src/App.tsx b/src/frontend/src/App.tsx
index 1079d13..be27815 100644
--- a/src/frontend/src/App.tsx
+++ b/src/frontend/src/App.tsx
@@ -47,6 +47,10 @@ export default function App() {
       const executing = tasks.filter((t) => isEdict(t) && t.state === 'executing').length;
       return executing + '活跃';
     }
+    if (key === 'mail') {
+      const unread = useStore.getState().mailUnread;
+      return unread > 0 ? String(unread) : '';
+    }
     return '';
   };