diff --git a/frontend/src/app/dashboard/page.tsx b/frontend/src/app/dashboard/page.tsx
index 165217b..80552a9 100644
--- a/frontend/src/app/dashboard/page.tsx
+++ b/frontend/src/app/dashboard/page.tsx
@@ -3,20 +3,41 @@
 import { useEffect, Suspense } from 'react';
 import { useRouter, useSearchParams } from 'next/navigation';
 import { useAuthStore } from '@/lib/auth-store';
-import { getUserInfo } from '@/lib/api';
 import Layout from '@/components/layout';
+import { Activity, BadgeCheck, Boxes, ShieldCheck } from 'lucide-react';
+
+const cards = [
+  {
+    title: '欢迎回来',
+    value: 'IMTIM Portal',
+    description: '您已成功登录企业门户',
+    icon: ShieldCheck,
+  },
+  {
+    title: '账户状态',
+    value: '已激活',
+    description: '当前账号可正常访问系统',
+    icon: BadgeCheck,
+  },
+  {
+    title: '系统版本',
+    value: '1.0.0',
+    description: '基础登录门户服务',
+    icon: Boxes,
+  },
+];
 
 function DashboardContent() {
-  const { login, initialize } = useAuthStore();
+  const { user, isAuthenticated, isInitialized, login, initialize } = useAuthStore();
   const router = useRouter();
   const searchParams = useSearchParams();
+  const token = searchParams.get('token');
 
   useEffect(() => {
     initialize();
   }, [initialize]);
 
   useEffect(() => {
-    const token = searchParams.get('token');
     if (token) {
       const fetchUser = async () => {
         try {
@@ -39,25 +60,74 @@ function DashboardContent() {
       };
       fetchUser();
     }
-  }, [searchParams, login, router]);
+  }, [token, login, router]);
+
+  useEffect(() => {
+    if (isInitialized && !isAuthenticated && !token) {
+      router.replace('/login');
+    }
+  }, [isInitialized, isAuthenticated, token, router]);
+
+  if (token || !isInitialized || !isAuthenticated) {
+    return (
+      <div className="mx-auto flex min-h-[calc(100svh-9.6rem)] w-full max-w-6xl items-center justify-center px-4 py-10 sm:px-6">
+        <div className="rounded-xl border bg-white px-5 py-4 text-sm text-muted-foreground shadow-sm">
+          加载中...
+        </div>
+      </div>
+    );
+  }
 
   return (
-    <div className="container mx-auto px-4 py-8">
-      <h1 className="text-3xl font-bold mb-6">仪表板</h1>
-      <div className="grid gap-6 md:grid-cols-2 lg:grid-cols-3">
-        <div className="rounded-lg border p-6 shadow-sm">
-          <h2 className="text-xl font-semibold mb-2">欢迎</h2>
-          <p className="text-muted-foreground">
-            您已成功登录 IMTIM Portal
+    <div className="mx-auto w-full max-w-6xl px-4 py-8 sm:px-6 sm:py-10">
+      <div className="mb-8 flex flex-col justify-between gap-4 sm:flex-row sm:items-end">
+        <div>
+          <p className="text-sm font-medium text-primary">控制台</p>
+          <h1 className="mt-2 text-3xl font-bold tracking-tight sm:text-4xl">仪表板</h1>
+          <p className="mt-3 max-w-2xl text-sm leading-6 text-muted-foreground sm:text-base">
+            {user?.username ? `${user.username}，查看登录状态、账户可用性和基础系统信息。` : '查看登录状态、账户可用性和基础系统信息。'}
           </p>
         </div>
-        <div className="rounded-lg border p-6 shadow-sm">
-          <h2 className="text-xl font-semibold mb-2">账户状态</h2>
-          <p className="text-green-600 font-medium">已激活</p>
+        <div className="inline-flex w-fit items-center gap-2 rounded-full border bg-white px-3 py-1.5 text-sm font-medium text-emerald-700 shadow-sm">
+          <Activity className="h-4 w-4" />
+          在线
         </div>
-        <div className="rounded-lg border p-6 shadow-sm">
-          <h2 className="text-xl font-semibold mb-2">系统信息</h2>
-          <p className="text-muted-foreground">版本 1.0.0</p>
+      </div>
+
+      <div className="grid gap-4 md:grid-cols-2 lg:grid-cols-3">
+        {cards.map((card) => {
+          const Icon = card.icon;
+          return (
+            <div key={card.title} className="rounded-xl border bg-white p-5 shadow-sm sm:p-6">
+              <div className="mb-5 flex items-center justify-between gap-4">
+                <span className="flex h-11 w-11 items-center justify-center rounded-lg bg-primary/10 text-primary">
+                  <Icon className="h-5 w-5" />
+                </span>
+                {card.title === '账户状态' ? (
+                  <span className="rounded-full bg-emerald-100 px-2.5 py-1 text-xs font-medium text-emerald-700">
+                    Active
+                  </span>
+                ) : null}
+              </div>
+              <h2 className="text-sm font-medium text-muted-foreground">{card.title}</h2>
+              <p className="mt-2 text-2xl font-semibold tracking-tight">{card.value}</p>
+              <p className="mt-2 text-sm leading-6 text-muted-foreground">{card.description}</p>
+            </div>
+          );
+        })}
+      </div>
+
+      <div className="mt-4 rounded-xl border bg-white p-5 shadow-sm sm:mt-6 sm:p-6">
+        <div className="flex flex-col gap-4 sm:flex-row sm:items-center sm:justify-between">
+          <div>
+            <h2 className="text-lg font-semibold">认证流程</h2>
+            <p className="mt-1 text-sm text-muted-foreground">
+              OAuth 回调、用户信息获取和本地会话写入均已就绪。
+            </p>
+          </div>
+          <span className="w-fit rounded-full bg-secondary px-3 py-1 text-sm font-medium text-secondary-foreground">
+            Ready
+          </span>
         </div>
       </div>
     </div>
@@ -67,7 +137,13 @@ function DashboardContent() {
 export default function DashboardPage() {
   return (
     <Layout>
-      <Suspense fallback={<div className="container mx-auto px-4 py-8">加载中...</div>}>
+      <Suspense
+        fallback={
+          <div className="mx-auto w-full max-w-6xl px-4 py-8 text-sm text-muted-foreground sm:px-6">
+            加载中...
+          </div>
+        }
+      >
         <DashboardContent />
       </Suspense>
     </Layout>
diff --git a/frontend/src/app/globals.css b/frontend/src/app/globals.css
index f1ee6bc..96e9cfe 100644
--- a/frontend/src/app/globals.css
+++ b/frontend/src/app/globals.css
@@ -1,34 +1,66 @@
 @import "tailwindcss";
 
 :root {
-  --background: oklch(1 0 0);
-  --foreground: oklch(0.145 0 0);
+  --background: oklch(0.985 0.006 247.858);
+  --foreground: oklch(0.21 0.034 264.665);
   --card: oklch(1 0 0);
-  --card-foreground: oklch(0.145 0 0);
+  --card-foreground: oklch(0.21 0.034 264.665);
   --popover: oklch(1 0 0);
-  --popover-foreground: oklch(0.145 0 0);
-  --primary: oklch(0.205 0 0);
+  --popover-foreground: oklch(0.21 0.034 264.665);
+  --primary: oklch(0.52 0.19 253.3);
   --primary-foreground: oklch(0.985 0 0);
-  --secondary: oklch(0.97 0 0);
-  --secondary-foreground: oklch(0.205 0 0);
-  --muted: oklch(0.97 0 0);
-  --muted-foreground: oklch(0.556 0 0);
-  --accent: oklch(0.97 0 0);
-  --accent-foreground: oklch(0.205 0 0);
+  --secondary: oklch(0.96 0.013 247.858);
+  --secondary-foreground: oklch(0.279 0.041 260.031);
+  --muted: oklch(0.96 0.013 247.858);
+  --muted-foreground: oklch(0.446 0.043 257.281);
+  --accent: oklch(0.94 0.025 255.585);
+  --accent-foreground: oklch(0.279 0.041 260.031);
   --destructive: oklch(0.577 0.245 27.325);
   --destructive-foreground: oklch(0.577 0.245 27.325);
-  --border: oklch(0.922 0 0);
-  --input: oklch(0.922 0 0);
-  --ring: oklch(0.708 0 0);
+  --border: oklch(0.9 0.022 252.894);
+  --input: oklch(0.9 0.022 252.894);
+  --ring: oklch(0.52 0.19 253.3);
   --radius: 0.5rem;
 }
 
+@theme inline {
+  --color-background: var(--background);
+  --color-foreground: var(--foreground);
+  --color-card: var(--card);
+  --color-card-foreground: var(--card-foreground);
+  --color-popover: var(--popover);
+  --color-popover-foreground: var(--popover-foreground);
+  --color-primary: var(--primary);
+  --color-primary-foreground: var(--primary-foreground);
+  --color-secondary: var(--secondary);
+  --color-secondary-foreground: var(--secondary-foreground);
+  --color-muted: var(--muted);
+  --color-muted-foreground: var(--muted-foreground);
+  --color-accent: var(--accent);
+  --color-accent-foreground: var(--accent-foreground);
+  --color-destructive: var(--destructive);
+  --color-destructive-foreground: var(--destructive-foreground);
+  --color-border: var(--border);
+  --color-input: var(--input);
+  --color-ring: var(--ring);
+}
+
 * {
   border-color: var(--border);
 }
 
+html {
+  min-width: 320px;
+  scroll-behavior: smooth;
+}
+
 body {
   background-color: var(--background);
   color: var(--foreground);
   font-family: system-ui, -apple-system, sans-serif;
 }
+
+button,
+a {
+  -webkit-tap-highlight-color: transparent;
+}
diff --git a/frontend/src/app/login/page.tsx b/frontend/src/app/login/page.tsx
index 60fe13a..2c0a99b 100644
--- a/frontend/src/app/login/page.tsx
+++ b/frontend/src/app/login/page.tsx
@@ -4,18 +4,22 @@ import { useEffect } from 'react';
 import { useRouter } from 'next/navigation';
 import { useAuthStore } from '@/lib/auth-store';
 import { getLoginUrl } from '@/lib/api';
-import { LogIn } from 'lucide-react';
+import { BadgeCheck, KeyRound, LogIn } from 'lucide-react';
 import Layout from '@/components/layout';
 
 export default function LoginPage() {
-  const { isAuthenticated } = useAuthStore();
+  const { isAuthenticated, isInitialized, initialize } = useAuthStore();
   const router = useRouter();
 
   useEffect(() => {
-    if (isAuthenticated) {
-      router.push('/dashboard');
+    initialize();
+  }, [initialize]);
+
+  useEffect(() => {
+    if (isInitialized && isAuthenticated) {
+      router.replace('/dashboard');
     }
-  }, [isAuthenticated, router]);
+  }, [isInitialized, isAuthenticated, router]);
 
   const handleLogin = async () => {
     try {
@@ -28,25 +32,66 @@ export default function LoginPage() {
 
   return (
     <Layout>
-      <div className="flex items-center justify-center min-h-[calc(100vh-12rem)]">
-        <div className="w-full max-w-md">
-          <div className="rounded-lg border p-8 shadow-sm">
-            <div className="text-center mb-8">
-              <h1 className="text-2xl font-bold mb-2">登录</h1>
-              <p className="text-muted-foreground">
+      <div className="mx-auto grid min-h-[calc(100svh-9.6rem)] w-full max-w-6xl items-center gap-10 px-4 py-10 sm:px-6 lg:grid-cols-[1fr_0.88fr]">
+        <section className="hidden lg:block">
+          <p className="text-sm font-medium text-primary">统一身份认证</p>
+          <h1 className="mt-3 max-w-xl text-4xl font-bold tracking-tight">
+            通过 Casdoor 安全接入 IMTIM Portal
+          </h1>
+          <div className="mt-8 grid max-w-xl gap-4">
+            <div className="rounded-xl border bg-white p-5 shadow-sm">
+              <div className="flex items-start gap-4">
+                <span className="flex h-10 w-10 shrink-0 items-center justify-center rounded-lg bg-primary/10 text-primary">
+                  <KeyRound className="h-5 w-5" />
+                </span>
+                <div>
+                  <h2 className="font-semibold">单点登录入口</h2>
+                  <p className="mt-1 text-sm leading-6 text-muted-foreground">
+                    使用统一账号完成认证，减少重复登录和权限分散。
+                  </p>
+                </div>
+              </div>
+            </div>
+            <div className="rounded-xl border bg-white p-5 shadow-sm">
+              <div className="flex items-start gap-4">
+                <span className="flex h-10 w-10 shrink-0 items-center justify-center rounded-lg bg-emerald-100 text-emerald-700">
+                  <BadgeCheck className="h-5 w-5" />
+                </span>
+                <div>
+                  <h2 className="font-semibold">认证状态同步</h2>
+                  <p className="mt-1 text-sm leading-6 text-muted-foreground">
+                    登录成功后自动写入会话并跳转到控制台。
+                  </p>
+                </div>
+              </div>
+            </div>
+          </div>
+        </section>
+
+        <section className="mx-auto w-full max-w-md lg:mx-0 lg:justify-self-end">
+          <div className="rounded-xl border bg-white p-6 shadow-sm sm:p-8">
+            <div className="mb-8">
+              <div className="mb-5 flex h-12 w-12 items-center justify-center rounded-xl bg-primary text-primary-foreground">
+                <LogIn className="h-6 w-6" />
+              </div>
+              <h1 className="text-2xl font-semibold tracking-tight">登录</h1>
+              <p className="mt-2 text-sm leading-6 text-muted-foreground">
                 使用 Casdoor 账号登录 IMTIM Portal
               </p>
             </div>
 
             <button
               onClick={handleLogin}
-              className="w-full flex items-center justify-center gap-2 px-4 py-3 text-sm font-medium rounded-md bg-primary text-primary-foreground hover:bg-primary/90 transition-colors"
+              className="flex h-12 w-full items-center justify-center gap-2 rounded-lg bg-primary px-4 text-sm font-medium text-primary-foreground shadow-sm transition-colors hover:bg-primary/90 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
             >
               <LogIn className="h-5 w-5" />
               <span>使用 Casdoor 登录</span>
             </button>
+            <p className="mt-5 text-center text-xs leading-5 text-muted-foreground">
+              登录即表示将跳转到 Casdoor 完成身份验证
+            </p>
           </div>
-        </div>
+        </section>
       </div>
     </Layout>
   );
diff --git a/frontend/src/app/page.tsx b/frontend/src/app/page.tsx
index 9f87232..c2bdac6 100644
--- a/frontend/src/app/page.tsx
+++ b/frontend/src/app/page.tsx
@@ -3,71 +3,121 @@
 import { useEffect } from 'react';
 import { useRouter } from 'next/navigation';
 import { useAuthStore } from '@/lib/auth-store';
-import { ArrowRight, Shield, Zap, Users } from 'lucide-react';
+import { ArrowRight, CheckCircle2, Shield, Users, Zap } from 'lucide-react';
 import Layout from '@/components/layout';
 
+const features = [
+  {
+    title: '安全可靠',
+    description: '基于 OAuth 2.0 的企业级认证，支持统一身份入口和多因素认证。',
+    icon: Shield,
+  },
+  {
+    title: '快速部署',
+    description: '面向容器化交付，适合快速接入现有服务并降低运维成本。',
+    icon: Zap,
+  },
+  {
+    title: '易于扩展',
+    description: '模块化架构设计，便于扩展自定义业务逻辑和第三方集成。',
+    icon: Users,
+  },
+];
+
+const metrics = [
+  ['OAuth 2.0', '认证协议'],
+  ['Docker', '部署方式'],
+  ['SSO', '统一登录'],
+];
+
 export default function Home() {
-  const { isAuthenticated, initialize } = useAuthStore();
+  const { initialize } = useAuthStore();
   const router = useRouter();
 
   useEffect(() => {
     initialize();
   }, [initialize]);
 
-  useEffect(() => {
-    if (isAuthenticated) {
-      router.push('/dashboard');
-    }
-  }, [isAuthenticated, router]);
-
   return (
     <Layout>
-      <div className="flex flex-col items-center">
-        {/* Hero Section */}
-        <section className="w-full py-24 bg-gradient-to-b from-background to-secondary/20">
-          <div className="container px-4 text-center">
-            <h1 className="text-4xl md:text-6xl font-bold tracking-tight mb-4">
-              IMTIM Portal
-            </h1>
-            <p className="text-xl text-muted-foreground mb-8 max-w-2xl mx-auto">
+      <div className="overflow-hidden">
+        <section className="border-b bg-[linear-gradient(180deg,white_0%,oklch(0.96_0.013_247.858)_100%)]">
+          <div className="mx-auto grid min-h-[calc(100svh-9.6rem)] w-full max-w-6xl items-center gap-10 px-4 py-12 sm:px-6 sm:py-16 lg:grid-cols-[1fr_0.84fr] lg:py-20">
+            <div className="max-w-2xl">
+              <div className="mb-5 inline-flex items-center gap-2 rounded-full border bg-white px-3 py-1 text-sm font-medium text-muted-foreground shadow-sm">
+                <CheckCircle2 className="h-4 w-4 text-emerald-600" />
+                企业登录基座
+              </div>
+              <h1 className="text-4xl font-bold tracking-tight text-foreground sm:text-5xl lg:text-6xl">
+                IMTIM Portal
+              </h1>
+              <p className="mt-5 max-w-xl text-base leading-7 text-muted-foreground sm:text-lg">
               企业级门户登录基座应用，安全、高效、易于扩展
-            </p>
-            <button
-              onClick={() => router.push('/login')}
-              className="inline-flex items-center gap-2 px-6 py-3 text-base font-medium rounded-md bg-primary text-primary-foreground hover:bg-primary/90"
-            >
-              开始使用
-              <ArrowRight className="h-5 w-5" />
-            </button>
+              </p>
+              <div className="mt-8 flex flex-col gap-3 sm:flex-row">
+                <button
+                  onClick={() => router.push('/login')}
+                  className="inline-flex h-12 items-center justify-center gap-2 rounded-lg bg-primary px-6 text-base font-medium text-primary-foreground shadow-sm transition hover:bg-primary/90 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
+                >
+                  开始使用
+                  <ArrowRight className="h-5 w-5" />
+                </button>
+                <button
+                  onClick={() => router.push('/dashboard')}
+                  className="inline-flex h-12 items-center justify-center rounded-lg border bg-white px-6 text-base font-medium shadow-sm transition hover:bg-accent focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring"
+                >
+                  查看控制台
+                </button>
+              </div>
+            </div>
+
+            <div className="rounded-xl border bg-white p-4 shadow-sm sm:p-5">
+              <div className="rounded-lg bg-secondary p-4">
+                <div className="flex items-center justify-between gap-4 border-b pb-4">
+                  <div>
+                    <p className="text-sm text-muted-foreground">身份服务状态</p>
+                    <p className="mt-1 text-2xl font-semibold">运行正常</p>
+                  </div>
+                  <span className="rounded-full bg-emerald-100 px-3 py-1 text-sm font-medium text-emerald-700">
+                    Active
+                  </span>
+                </div>
+                <div className="mt-4 grid gap-3 sm:grid-cols-3 lg:grid-cols-1 xl:grid-cols-3">
+                  {metrics.map(([value, label]) => (
+                    <div key={label} className="rounded-lg bg-white p-4">
+                      <p className="text-lg font-semibold">{value}</p>
+                      <p className="mt-1 text-sm text-muted-foreground">{label}</p>
+                    </div>
+                  ))}
+                </div>
+              </div>
+            </div>
           </div>
         </section>
 
-        {/* Features Section */}
-        <section className="w-full py-16">
-          <div className="container px-4">
-            <h2 className="text-3xl font-bold text-center mb-12">核心特性</h2>
-            <div className="grid gap-8 md:grid-cols-3 max-w-5xl mx-auto">
-              <div className="rounded-lg border p-6 text-center">
-                <Shield className="h-12 w-12 mx-auto mb-4 text-primary" />
-                <h3 className="text-xl font-semibold mb-2">安全可靠</h3>
-                <p className="text-muted-foreground">
-                  基于 OAuth 2.0 的企业级认证，支持多因素认证
-                </p>
-              </div>
-              <div className="rounded-lg border p-6 text-center">
-                <Zap className="h-12 w-12 mx-auto mb-4 text-primary" />
-                <h3 className="text-xl font-semibold mb-2">快速部署</h3>
-                <p className="text-muted-foreground">
-                  Docker 一键部署，开箱即用，降低运维成本
-                </p>
-              </div>
-              <div className="rounded-lg border p-6 text-center">
-                <Users className="h-12 w-12 mx-auto mb-4 text-primary" />
-                <h3 className="text-xl font-semibold mb-2">易于扩展</h3>
-                <p className="text-muted-foreground">
-                  模块化架构设计，支持自定义业务逻辑和第三方集成
-                </p>
-              </div>
+        <section className="bg-white py-12 sm:py-16">
+          <div className="mx-auto w-full max-w-6xl px-4 sm:px-6">
+            <div className="max-w-2xl">
+              <h2 className="text-2xl font-semibold tracking-tight sm:text-3xl">核心特性</h2>
+              <p className="mt-3 text-muted-foreground">
+                围绕认证、部署和扩展体验整理基础能力，适合作为内部系统统一入口。
+              </p>
+            </div>
+            <div className="mt-8 grid gap-4 sm:grid-cols-2 lg:grid-cols-3">
+              {features.map((feature) => {
+                const Icon = feature.icon;
+                return (
+                  <div key={feature.title} className="rounded-xl border bg-card p-6 shadow-sm">
+                    <div className="mb-5 flex h-11 w-11 items-center justify-center rounded-lg bg-primary/10 text-primary">
+                      <Icon className="h-5 w-5" />
+                    </div>
+                    <h3 className="text-lg font-semibold">{feature.title}</h3>
+                    <p className="mt-2 text-sm leading-6 text-muted-foreground">
+                      {feature.description}
+                    </p>
+                  </div>
+                );
+              })}
             </div>
           </div>
         </section>
diff --git a/frontend/src/components/header.tsx b/frontend/src/components/header.tsx
index 68260af..1138706 100644
--- a/frontend/src/components/header.tsx
+++ b/frontend/src/components/header.tsx
@@ -1,7 +1,7 @@
 import Link from 'next/link';
 import { useAuthStore } from '@/lib/auth-store';
 import { getLoginUrl } from '@/lib/api';
-import { LogOut, User } from 'lucide-react';
+import { LogIn, LogOut, User } from 'lucide-react';
 import * as Avatar from '@radix-ui/react-avatar';
 import * as DropdownMenu from '@radix-ui/react-dropdown-menu';
 
@@ -23,18 +23,23 @@ export default function Header() {
   };
 
   return (
-    <header className="border-b bg-background/95 backdrop-blur supports-[backdrop-filter]:bg-background/60">
-      <div className="container flex h-16 items-center justify-between px-4">
-        <Link href="/" className="text-xl font-bold">
-          IMTIM Portal
+    <header className="sticky top-0 z-40 border-b bg-white/85 backdrop-blur-xl supports-[backdrop-filter]:bg-white/70">
+      <div className="mx-auto flex h-16 w-full max-w-6xl items-center justify-between gap-3 px-4 sm:px-6">
+        <Link href="/" className="flex min-w-0 items-center gap-3">
+          <span className="flex h-9 w-9 shrink-0 items-center justify-center rounded-lg bg-primary text-sm font-bold text-primary-foreground shadow-sm">
+            IM
+          </span>
+          <span className="truncate text-base font-semibold tracking-tight sm:text-lg">
+            IMTIM Portal
+          </span>
         </Link>
 
-        <nav className="flex items-center gap-4">
+        <nav className="flex shrink-0 items-center gap-2">
           {isAuthenticated && user ? (
             <DropdownMenu.Root>
               <DropdownMenu.Trigger asChild>
-                <button className="flex items-center gap-2 rounded-full hover:bg-accent p-1">
-                  <Avatar.Root className="h-8 w-8 rounded-full bg-secondary flex items-center justify-center overflow-hidden">
+                <button className="flex max-w-[44vw] items-center gap-2 rounded-full border bg-white p-1 pr-2 text-left shadow-sm transition hover:bg-accent focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring sm:max-w-none sm:pr-3">
+                  <Avatar.Root className="flex h-8 w-8 shrink-0 items-center justify-center overflow-hidden rounded-full bg-secondary">
                     {user.avatar ? (
                       <Avatar.Image
                         src={user.avatar}
@@ -47,16 +52,17 @@ export default function Header() {
                       </Avatar.Fallback>
                     )}
                   </Avatar.Root>
-                  <span className="text-sm font-medium">{user.username}</span>
+                  <span className="truncate text-sm font-medium">{user.username}</span>
                 </button>
               </DropdownMenu.Trigger>
 
               <DropdownMenu.Portal>
                 <DropdownMenu.Content
-                  className="min-w-[220px] bg-popover rounded-md p-1 shadow-md border"
+                  className="z-50 min-w-56 rounded-lg border bg-popover p-1.5 shadow-xl"
+                  align="end"
                   sideOffset={5}
                 >
-                  <DropdownMenu.Item className="flex items-center gap-2 px-3 py-2 text-sm rounded cursor-pointer hover:bg-accent outline-none">
+                  <DropdownMenu.Item className="flex cursor-pointer items-center gap-2 rounded-md px-3 py-2 text-sm outline-none hover:bg-accent focus:bg-accent">
                     <User className="h-4 w-4" />
                     <span>个人资料</span>
                   </DropdownMenu.Item>
@@ -64,7 +70,7 @@ export default function Header() {
                   <DropdownMenu.Separator className="h-px bg-border my-1" />
                   
                   <DropdownMenu.Item
-                    className="flex items-center gap-2 px-3 py-2 text-sm rounded cursor-pointer hover:bg-accent text-red-600 outline-none"
+                    className="flex cursor-pointer items-center gap-2 rounded-md px-3 py-2 text-sm text-red-600 outline-none hover:bg-red-50 focus:bg-red-50"
                     onClick={handleLogout}
                   >
                     <LogOut className="h-4 w-4" />
@@ -76,9 +82,10 @@ export default function Header() {
           ) : (
             <button
               onClick={handleLogin}
-              className="px-4 py-2 text-sm font-medium rounded-md bg-primary text-primary-foreground hover:bg-primary/90"
+              className="inline-flex h-10 items-center justify-center gap-2 rounded-lg bg-primary px-3 text-sm font-medium text-primary-foreground shadow-sm transition hover:bg-primary/90 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring sm:px-4"
             >
-              登录
+              <LogIn className="h-4 w-4" />
+              <span>登录</span>
             </button>
           )}
         </nav>
diff --git a/frontend/src/components/layout.tsx b/frontend/src/components/layout.tsx
index 02ab898..a3834d6 100644
--- a/frontend/src/components/layout.tsx
+++ b/frontend/src/components/layout.tsx
@@ -6,11 +6,11 @@ export default function RootLayout({
   children: React.ReactNode;
 }) {
   return (
-    <div className="min-h-screen flex flex-col">
+    <div className="flex min-h-screen flex-col bg-background text-foreground">
       <Header />
       <main className="flex-1">{children}</main>
-      <footer className="border-t py-6">
-        <div className="container px-4 text-center text-sm text-muted-foreground">
+      <footer className="border-t bg-white/70 py-5">
+        <div className="mx-auto w-full max-w-6xl px-4 text-center text-xs text-muted-foreground sm:px-6">
           © 2026 IMTIM Portal. All rights reserved.
         </div>
       </footer>
diff --git a/frontend/src/components/protected-route.tsx b/frontend/src/components/protected-route.tsx
index b3032ec..88a7c8a 100644
--- a/frontend/src/components/protected-route.tsx
+++ b/frontend/src/components/protected-route.tsx
@@ -5,7 +5,7 @@ import { useRouter } from 'next/navigation';
 import { useAuthStore } from '@/lib/auth-store';
 
 export default function ProtectedRoute({ children }: { children: React.ReactNode }) {
-  const { isAuthenticated, initialize } = useAuthStore();
+  const { isAuthenticated, isInitialized, initialize } = useAuthStore();
   const router = useRouter();
 
   useEffect(() => {
@@ -13,15 +13,17 @@ export default function ProtectedRoute({ children }: { children: React.ReactNode
   }, [initialize]);
 
   useEffect(() => {
-    if (!isAuthenticated) {
-      router.push('/login');
+    if (isInitialized && !isAuthenticated) {
+      router.replace('/login');
     }
-  }, [isAuthenticated, router]);
+  }, [isInitialized, isAuthenticated, router]);
 
-  if (!isAuthenticated) {
+  if (!isInitialized || !isAuthenticated) {
     return (
-      <div className="flex items-center justify-center min-h-[200px]">
-        <div className="text-muted-foreground">加载中...</div>
+      <div className="mx-auto flex min-h-[calc(100svh-9.6rem)] w-full max-w-6xl items-center justify-center px-4 py-10 sm:px-6">
+        <div className="rounded-xl border bg-white px-5 py-4 text-sm text-muted-foreground shadow-sm">
+          加载中...
+        </div>
       </div>
     );
   }
diff --git a/frontend/src/lib/auth-store.ts b/frontend/src/lib/auth-store.ts
index f828066..938f33f 100644
--- a/frontend/src/lib/auth-store.ts
+++ b/frontend/src/lib/auth-store.ts
@@ -13,6 +13,7 @@ interface AuthState {
   user: User | null;
   token: string | null;
   isAuthenticated: boolean;
+  isInitialized: boolean;
   login: (token: string, user: User) => void;
   logout: () => void;
   initialize: () => void;
@@ -22,6 +23,7 @@ export const useAuthStore = create<AuthState>((set) => ({
   user: null,
   token: null,
   isAuthenticated: false,
+  isInitialized: false,
   
   login: (token, user) => {
     if (typeof window !== 'undefined') {
@@ -36,7 +38,7 @@ export const useAuthStore = create<AuthState>((set) => ({
       localStorage.removeItem('token');
       localStorage.removeItem('user');
     }
-    set({ user: null, token: null, isAuthenticated: false });
+    set({ user: null, token: null, isAuthenticated: false, isInitialized: true });
   },
   
   initialize: () => {
@@ -44,12 +46,20 @@ export const useAuthStore = create<AuthState>((set) => ({
       const token = localStorage.getItem('token');
       const userStr = localStorage.getItem('user');
       if (token && userStr) {
-        set({
-          token,
-          user: JSON.parse(userStr),
-          isAuthenticated: true,
-        });
+        try {
+          set({
+            token,
+            user: JSON.parse(userStr),
+            isAuthenticated: true,
+            isInitialized: true,
+          });
+          return;
+        } catch {
+          localStorage.removeItem('token');
+          localStorage.removeItem('user');
+        }
       }
     }
+    set({ user: null, token: null, isAuthenticated: false, isInitialized: true });
   },
 }));