Index: chapterx-frontend/src/store/notificationStore.ts
===================================================================
--- chapterx-frontend/src/store/notificationStore.ts	(revision b62cefc14094ca5ac7154f7d48797a1e6c444935)
+++ chapterx-frontend/src/store/notificationStore.ts	(revision b62cefc14094ca5ac7154f7d48797a1e6c444935)
@@ -0,0 +1,42 @@
+import { create } from 'zustand'
+import { Notification } from '../types'
+import { mockNotifications } from '../data/mockData'
+
+interface NotificationStore {
+  notifications: Notification[]
+  addNotification: (n: Omit<Notification, 'notification_id' | 'created_at' | 'is_read'>) => void
+  markAllRead: () => void
+  markRead: (id: number) => void
+  getUnreadCount: () => number
+}
+
+export const useNotificationStore = create<NotificationStore>((set, get) => ({
+  notifications: [...mockNotifications],
+
+  addNotification: (n) =>
+    set(state => ({
+      notifications: [
+        {
+          ...n,
+          notification_id: Date.now(),
+          created_at: new Date().toISOString(),
+          is_read: false,
+        },
+        ...state.notifications,
+      ],
+    })),
+
+  markAllRead: () =>
+    set(state => ({
+      notifications: state.notifications.map(n => ({ ...n, is_read: true })),
+    })),
+
+  markRead: (id) =>
+    set(state => ({
+      notifications: state.notifications.map(n =>
+        n.notification_id === id ? { ...n, is_read: true } : n
+      ),
+    })),
+
+  getUnreadCount: () => get().notifications.filter(n => !n.is_read).length,
+}))