diff --git a/src/auth/permissions.ts b/src/auth/permissions.ts
index 6999b32..336c635 100644
--- a/src/auth/permissions.ts
+++ b/src/auth/permissions.ts
@@ -1,5 +1,6 @@
 import { redirect } from '@tanstack/react-router'
 import { can, useAuthStore } from '@/auth/store'
+import { getFirstAccessibleRoute } from '@/components/layout/nav'
 
 /**
  * Admin permission keys — mirrors the backend catalog
@@ -50,6 +51,7 @@ export type Permission = (typeof PERM)[keyof typeof PERM]
 export function requirePermission(permission: Permission): void {
   const { user } = useAuthStore.getState()
   if (user && !can(permission)) {
-    throw redirect({ to: '/' })
+    const target = getFirstAccessibleRoute()
+    throw redirect({ to: target && target !== '/' ? target : '/' })
   }
 }
diff --git a/src/auth/store.ts b/src/auth/store.ts
index cfebaa7..2fc256d 100644
--- a/src/auth/store.ts
+++ b/src/auth/store.ts
@@ -51,5 +51,8 @@ export function useCan(permission: string): boolean {
 }
 
 export function isAuthenticated(): boolean {
-  return Boolean(useAuthStore.getState().accessToken)
+  const { accessToken, user, roles, permissions } = useAuthStore.getState()
+  if (!accessToken) return false
+  if (user && roles.length === 0 && permissions.length === 0) return false
+  return true
 }
diff --git a/src/components/layout/nav.ts b/src/components/layout/nav.ts
index 2a55508..6f0b418 100644
--- a/src/components/layout/nav.ts
+++ b/src/components/layout/nav.ts
@@ -1,4 +1,5 @@
 import type { LucideIcon } from 'lucide-react'
+import { can } from '@/auth/store'
 import {
   BookOpenText,
   Bot,
@@ -100,3 +101,15 @@ export const NAV_GROUPS: NavGroup[] = [
     ],
   },
 ]
+
+export function getFirstAccessibleRoute(): string | null {
+  for (const group of NAV_GROUPS) {
+    for (const item of group.items) {
+      if (!item.permission || can(item.permission)) {
+        return item.to
+      }
+    }
+  }
+  return null
+}
+
diff --git a/src/routes/_authed.tsx b/src/routes/_authed.tsx
index 6ef0d9b..0299e89 100644
--- a/src/routes/_authed.tsx
+++ b/src/routes/_authed.tsx
@@ -2,6 +2,7 @@ import { Link, Outlet, createFileRoute, redirect, useNavigate } from '@tanstack/
 import { useQuery } from '@tanstack/react-query'
 import { useEffect } from 'react'
 import { LogOut, Moon, Sun } from 'lucide-react'
+import { toast } from 'sonner'
 import { fetchMe } from '@/api/modules/auth'
 import { can, isAuthenticated, useAuthStore } from '@/auth/store'
 import { NAV_GROUPS } from '@/components/layout/nav'
@@ -41,11 +42,19 @@ function AuthedLayout() {
 
   useEffect(() => {
     if (me.data) {
+      const roles = me.data.meta?.roles ?? []
+      const permissions = me.data.meta?.permissions ?? []
+      if (roles.length === 0 && permissions.length === 0) {
+        useAuthStore.getState().clear()
+        toast.error('账号未分配管理后台权限，已退出登录')
+        void navigate({ to: '/login' })
+        return
+      }
       useAuthStore
         .getState()
-        .setSession(me.data.data, me.data.meta?.roles ?? [], me.data.meta?.permissions ?? [])
+        .setSession(me.data.data, roles, permissions)
     }
-  }, [me.data])
+  }, [me.data, navigate])
 
   useEffect(() => {
     if (me.isError && !isAuthenticated()) {
diff --git a/src/routes/_authed/index.tsx b/src/routes/_authed/index.tsx
index c4e9b07..eddf529 100644
--- a/src/routes/_authed/index.tsx
+++ b/src/routes/_authed/index.tsx
@@ -1,7 +1,51 @@
-import { createFileRoute, redirect } from '@tanstack/react-router'
+import { createFileRoute, redirect, useNavigate } from '@tanstack/react-router'
+import { ShieldAlert, LogOut } from 'lucide-react'
+import { getFirstAccessibleRoute } from '@/components/layout/nav'
+import { useAuthStore } from '@/auth/store'
+import { Button } from '@/components/ui/button'
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from '@/components/ui/card'
 
 export const Route = createFileRoute('/_authed/')({
   beforeLoad: () => {
-    throw redirect({ to: '/categories' })
+    const target = getFirstAccessibleRoute()
+    if (target && target !== '/') {
+      throw redirect({ to: target })
+    }
   },
+  component: DashboardIndexPage,
 })
+
+function DashboardIndexPage() {
+  const navigate = useNavigate()
+  const user = useAuthStore((s) => s.user)
+
+  const logout = () => {
+    useAuthStore.getState().clear()
+    void navigate({ to: '/login' })
+  }
+
+  return (
+    <div className="flex min-h-[60vh] items-center justify-center p-4">
+      <Card className="w-full max-w-md text-center shadow-xs">
+        <CardHeader>
+          <div className="mx-auto mb-2 flex size-12 items-center justify-center rounded-full bg-amber-500/10 text-amber-600 dark:bg-amber-500/20 dark:text-amber-400">
+            <ShieldAlert className="size-6" />
+          </div>
+          <CardTitle className="text-xl">账号未分配权限</CardTitle>
+          <CardDescription>
+            当前账号【{user?.display_name ?? user?.username ?? user?.uid}】尚未分配任何管理后台权限
+          </CardDescription>
+        </CardHeader>
+        <CardContent className="space-y-4">
+          <p className="text-xs text-muted-foreground">
+            如果您需要访问管理后台，请联系超级管理员在「用户角色」管理中为您分配相应的角色。
+          </p>
+          <Button variant="outline" onClick={logout} className="gap-2">
+            <LogOut className="size-4" />
+            退出登录
+          </Button>
+        </CardContent>
+      </Card>
+    </div>
+  )
+}
diff --git a/src/routes/login.tsx b/src/routes/login.tsx
index b48a421..a555ef0 100644
--- a/src/routes/login.tsx
+++ b/src/routes/login.tsx
@@ -45,7 +45,13 @@ function LoginPage() {
 
       const me = await fetchMe()
       const roles = me.meta?.roles ?? []
-      useAuthStore.getState().setSession(me.data, roles, me.meta?.permissions ?? [])
+      const permissions = me.meta?.permissions ?? []
+      if (roles.length === 0 && permissions.length === 0) {
+        useAuthStore.getState().clear()
+        toast.error('该账号未分配管理后台权限，无法登录')
+        return
+      }
+      useAuthStore.getState().setSession(me.data, roles, permissions)
 
       await navigate({ to: '/' })
     } catch (error) {