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deleted file mode 100644
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new file mode 100644
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diff --git a/frontend/src/App.jsx b/frontend/src/App.jsx
index 6d573fc..eabb62f 100644
--- a/frontend/src/App.jsx
+++ b/frontend/src/App.jsx
@@ -1,6 +1,8 @@
+import { useEffect } from 'react'
 import { BrowserRouter, Routes, Route, Navigate, useParams, Outlet } from 'react-router-dom'
-import { ConfigProvider } from 'antd'
+import { ConfigProvider, theme } from 'antd'
 import zhCN from 'antd/locale/zh_CN'
+import useThemeStore from '@/stores/themeStore'
 import Login from '@/pages/Login/Login'
 import ProjectList from '@/pages/ProjectList/ProjectList'
 import DocumentPage from '@/pages/Document/DocumentPage'
@@ -35,8 +37,23 @@ function LayoutWrapper() {
 }
 
 function App() {
+  const { isDarkMode } = useThemeStore()
+
+  useEffect(() => {
+    if (isDarkMode) {
+      document.body.classList.add('dark')
+    } else {
+      document.body.classList.remove('dark')
+    }
+  }, [isDarkMode])
+
   return (
-    <ConfigProvider locale={zhCN}>
+    <ConfigProvider
+      locale={zhCN}
+      theme={{
+        algorithm: isDarkMode ? theme.darkAlgorithm : theme.defaultAlgorithm,
+      }}
+    >
       <BrowserRouter>
         <Routes>
           <Route path="/login" element={<Login />} />
diff --git a/frontend/src/assets/logo-small.png b/frontend/src/assets/logo-small.png
deleted file mode 100644
index 099c476..0000000
Binary files a/frontend/src/assets/logo-small.png and /dev/null differ
diff --git a/frontend/src/components/MainLayout/AppHeader.css b/frontend/src/components/MainLayout/AppHeader.css
index 10b0574..6429ab2 100644
--- a/frontend/src/components/MainLayout/AppHeader.css
+++ b/frontend/src/components/MainLayout/AppHeader.css
@@ -1,12 +1,13 @@
 .app-header {
-  background: #fff;
+  background: var(--header-bg);
   padding: 0 24px;
   display: flex;
   align-items: center;
   justify-content: space-between;
   box-shadow: 0 1px 4px rgba(0, 21, 41, 0.08);
   height: 64px;
-  border-bottom: 1px solid #f0f0f0;
+  border-bottom: 1px solid var(--border-color);
+  color: var(--text-color);
 }
 
 /* 左侧区域 */
@@ -25,26 +26,13 @@
   transition: width 0.2s;
 }
 
-.logo-small {
-  width: 40px;
-  height: 40px;
-  border-radius: 8px;
-  transition: all 0.2s;
-}
-
-.logo-full {
-  height: 32px;
-  width: auto;
-  transition: all 0.2s;
-}
-
 .trigger {
   font-size: 18px;
   cursor: pointer;
   transition: color 0.3s;
   padding: 8px;
   border-radius: 4px;
-  color: rgba(0, 0, 0, 0.65);
+  color: var(--text-color-secondary);
   display: flex;
   align-items: center;
 }
@@ -61,67 +49,29 @@
   gap: 16px;
 }
 
-.header-search {
-  border-radius: 16px;
-}
-
 .header-actions {
   display: flex;
   align-items: center;
+  gap: 16px;
 }
 
-.header-icon {
-  font-size: 16px;
-  color: rgba(0, 0, 0, 0.65);
-  cursor: pointer;
-  transition: all 0.3s;
-  padding: 8px;
-  border-radius: 4px;
+/* Icon Buttons */
+.header-icon-btn {
   display: flex;
   align-items: center;
   justify-content: center;
-}
-
-.header-icon:hover {
-  color: #1677ff;
-  background: rgba(22, 119, 255, 0.08);
-}
-
-.header-link {
-  font-size: 14px;
-  color: rgba(0, 0, 0, 0.65);
+  width: 40px;
+  height: 40px;
+  border-radius: 8px;
   cursor: pointer;
-  transition: all 0.3s;
-  padding: 6px 12px;
-  border-radius: 4px;
-  display: flex;
-  align-items: center;
-  gap: 4px;
+  color: var(--text-color-secondary);
+  transition: all 0.2s;
+  background: transparent;
 }
 
-.header-link:hover {
-  color: #1677ff;
-  background: rgba(22, 119, 255, 0.08);
-}
-
-.user-info {
-  display: flex;
-  align-items: center;
-  gap: 8px;
-  cursor: pointer;
-  padding: 4px 8px;
-  border-radius: 4px;
-  transition: all 0.3s;
-}
-
-.user-info:hover {
-  background: rgba(22, 119, 255, 0.08);
-}
-
-.username {
-  font-size: 14px;
-  color: rgba(0, 0, 0, 0.88);
-  font-weight: 500;
+.header-icon-btn:hover {
+  background-color: var(--item-hover-bg);
+  color: var(--text-color);
 }
 
 /* 通知面板样式 */
@@ -135,7 +85,7 @@
 
 .popover-header {
   padding: 12px 16px;
-  border-bottom: 1px solid #f0f0f0;
+  border-bottom: 1px solid var(--border-color);
   display: flex;
   justify-content: space-between;
   align-items: center;
@@ -144,6 +94,7 @@
 .popover-header .title {
   font-weight: 600;
   font-size: 16px;
+  color: var(--text-color);
 }
 
 .notification-list {
@@ -155,23 +106,33 @@
   padding: 12px 16px !important;
   cursor: pointer;
   transition: background 0.3s;
+  background: var(--bg-color);
 }
 
 .notification-item:hover {
-  background: #f5f5f5;
+  background: var(--item-hover-bg);
 }
 
 .notification-item.unread {
   background: #e6f7ff;
 }
 
+/* Dark mode adjustment for unread */
+body.dark .notification-item.unread {
+  background: #111d2c;
+}
+
 .notification-item.unread:hover {
   background: #bae7ff;
 }
 
+body.dark .notification-item.unread:hover {
+  background: #112a45;
+}
+
 .content-text {
   font-size: 13px;
-  color: #595959;
+  color: var(--text-color-secondary);
   margin-top: 4px;
   display: -webkit-box;
   -webkit-line-clamp: 2;
@@ -181,16 +142,13 @@
 
 .time {
   font-size: 12px;
-  color: #bfbfbf;
+  color: var(--text-color-secondary);
+  opacity: 0.8;
   margin-top: 4px;
 }
 
 .popover-footer {
   padding: 8px;
-  border-top: 1px solid #f0f0f0;
+  border-top: 1px solid var(--border-color);
   text-align: center;
-}
-
-.ml-1 {
-  margin-left: 4px;
 }
\ No newline at end of file
diff --git a/frontend/src/components/MainLayout/AppHeader.jsx b/frontend/src/components/MainLayout/AppHeader.jsx
index c5b88ad..ddb3bf7 100644
--- a/frontend/src/components/MainLayout/AppHeader.jsx
+++ b/frontend/src/components/MainLayout/AppHeader.jsx
@@ -1,68 +1,41 @@
 import { useState, useEffect } from 'react'
-import { Layout, Badge, Avatar, Dropdown, Space, Popover, List, Tabs, Button, Empty, Typography } from 'antd'
+import { Layout, Badge, Avatar, Dropdown, Space, Popover, List, Tabs, Button, Empty, Typography, Segmented, Tooltip } from 'antd'
 import { useNavigate } from 'react-router-dom'
 import {
   MenuFoldOutlined,
   MenuUnfoldOutlined,
   BellOutlined,
-  QuestionCircleOutlined,
-  FileTextOutlined,
-  CustomerServiceOutlined,
-  UserOutlined,
-  CheckOutlined,
   ProjectOutlined,
   TeamOutlined,
   NotificationOutlined,
+  MoonOutlined,
+  SunOutlined,
+  GlobalOutlined
 } from '@ant-design/icons'
 import useUserStore from '@/stores/userStore'
 import useNotificationStore from '@/stores/notificationStore'
+import useThemeStore from '@/stores/themeStore'
 import { getNotifications, getUnreadCount, markAsRead, markAllAsRead } from '@/api/notification'
 import Toast from '@/components/Toast/Toast'
-import headerMenuData from '../../data/headerMenuData.json'
 import './AppHeader.css'
 
 const { Header } = Layout
 const { Text } = Typography
 
-// 图标映射
-const iconMap = {
-  QuestionCircleOutlined: <QuestionCircleOutlined />,
-  FileTextOutlined: <FileTextOutlined />,
-  CustomerServiceOutlined: <CustomerServiceOutlined />,
-}
-
-function AppHeader({ collapsed, onToggle }) {
+function AppHeader({ collapsed, onToggle, showLogo = true }) {
   const navigate = useNavigate()
-  const { user, logout } = useUserStore()
+  const { user } = useUserStore()
   const { unreadCount, fetchUnreadCount, decrementUnreadCount, resetUnreadCount } = useNotificationStore()
-
-  // 用户下拉菜单
-  const userMenuItems = [
-    {
-      key: 'profile',
-      label: '个人中心',
-    },
-    {
-      key: 'settings',
-      label: '账户设置',
-    },
-    {
-      type: 'divider',
-    },
-    {
-      key: 'logout',
-      label: '退出登录',
-    },
-  ]
+  const { isDarkMode, toggleTheme } = useThemeStore()
 
   const [notifications, setNotifications] = useState([])
   const [loading, setLoading] = useState(false)
   const [popoverVisible, setPopoverVisible] = useState(false)
+  const [lang, setLang] = useState('zh')
 
   useEffect(() => {
     if (user) {
       fetchUnreadCount()
-      // 每 2 分钟轮询一次
       const timer = setInterval(fetchUnreadCount, 120000)
       return () => clearInterval(timer)
     }
@@ -83,7 +56,7 @@ function AppHeader({ collapsed, onToggle }) {
   const handleMarkRead = async (id) => {
     try {
       await markAsRead(id)
-      setNotifications(notifications.map(n => n.id === id ? { ...n, is_read: 1 } : n))
+      setNotifications(notifications.map(n => n.id === id ? { ...n, is_read: true } : n))
       decrementUnreadCount()
     } catch (error) {
       console.error('Mark read error:', error)
@@ -93,7 +66,7 @@ function AppHeader({ collapsed, onToggle }) {
   const handleMarkAllRead = async () => {
     try {
       await markAllAsRead()
-      setNotifications(notifications.map(n => ({ ...n, is_read: 1 })))
+      setNotifications(notifications.map(n => ({ ...n, is_read: true })))
       resetUnreadCount()
       Toast.success('操作成功', '所有通知已标记为已读')
     } catch (error) {
@@ -161,73 +134,46 @@ function AppHeader({ collapsed, onToggle }) {
     </div>
   )
 
-  const handleUserMenuClick = ({ key }) => {
-    if (key === 'logout') {
-      logout()
-      Toast.success('退出成功', '您已安全退出')
-      navigate('/login')
-    } else if (key === 'profile') {
-      navigate('/profile')
-    } else if (key === 'settings') {
-      Toast.info('开发中', '账户设置功能正在开发中')
-    }
-  }
-
-  const handleHeaderMenuClick = (key) => {
-    console.log('Header menu clicked:', key)
-    if (key === 'support') {
-      Toast.info('开发中', '支持功能正在开发中')
-    }
-  }
-
-  // 获取用户头像URL
-  const getUserAvatarUrl = () => {
-    if (!user?.avatar) return null
-    // avatar 字段存储的是相对路径，如：2/avatar/xxx.jpg
-    // 需要转换为 API 端点: /api/v1/auth/avatar/{user_id}/{filename}
-    const parts = user.avatar.split('/')
-    if (parts.length >= 3) {
-      const userId = parts[0]
-      const filename = parts[2]
-      return `/api/v1/auth/avatar/${userId}/${filename}`
-    }
-    return null
-  }
-
   return (
-    <Header className="app-header">
+    <Header className="app-header" style={{ paddingLeft: showLogo ? 24 : 0 }}>
       {/* 左侧：Logo + 折叠按钮 */}
-      <div className="header-left">
-        {/* Logo 区域 */}
-        <div className="header-logo">
-          <img src="/favicon.svg" alt="logo" style={{ width: 32, height: 32, marginRight: 8 }} />
-          <h2 style={{ margin: 0, color: '#1677ff', fontWeight: 'bold' }}>NexDocus</h2>
-        </div>
+      {showLogo && (
+        <div className="header-left">
+          {/* Logo 区域 */}
+          <div className="header-logo">
+            <img src="/favicon.svg" alt="logo" style={{ width: 32, height: 32, marginRight: 8 }} />
+            <h2 style={{ margin: 0, color: '#1677ff', fontWeight: 'bold' }}>NexDocus</h2>
+          </div>
 
-        {/* 折叠按钮 */}
-        <div className="trigger" onClick={onToggle}>
-          {collapsed ? <MenuUnfoldOutlined /> : <MenuFoldOutlined />}
+          {/* 折叠按钮 */}
+          <div className="trigger" onClick={onToggle}>
+            {collapsed ? <MenuUnfoldOutlined /> : <MenuFoldOutlined />}
+          </div>
         </div>
-      </div>
+      )}
+      {!showLogo && <div />} {/* Spacer if left is empty */}
 
-      {/* 右侧：功能按钮 + 用户信息 */}
+      {/* 右侧：功能按钮 */}
       <div className="header-right">
-        {/* 功能图标 */}
         <Space size={16} className="header-actions">
-          {/* 动态渲染 header 菜单 */}
-          {headerMenuData.map((item) => (
-            <div
-              key={item.key}
-              className="header-link"
-              title={item.label}
-              onClick={() => handleHeaderMenuClick(item.key)}
-            >
-              {iconMap[item.icon]}
-              <span className="ml-1">{item.label}</span>
-            </div>
-          ))}
+          
+          {/* 1. 主题切换 */}
+          <div className="header-icon-btn" title="切换主题" onClick={toggleTheme}>
+            {isDarkMode ? <SunOutlined style={{ fontSize: 18 }} /> : <MoonOutlined style={{ fontSize: 18 }} />}
+          </div>
 
-          {/* 消息中心 */}
+          {/* 2. 语言切换 */}
+          <Segmented
+            value={lang}
+            onChange={setLang}
+            options={[
+              { label: '中', value: 'zh' },
+              { label: 'EN', value: 'en' },
+            ]}
+            style={{ fontWeight: 500 }}
+          />
+
+          {/* 3. 消息通知 */}
           <Popover
             content={notificationContent}
             trigger="click"
@@ -241,31 +187,17 @@ function AppHeader({ collapsed, onToggle }) {
             placement="bottomRight"
             overlayClassName="header-notification-popover"
           >
-            <div className="header-link" title="消息中心">
-              <Badge count={unreadCount} size="small" offset={[4, -2]}>
-                <BellOutlined />
+            <div className="header-icon-btn" title="消息中心">
+              <Badge count={unreadCount} size="small" offset={[2, -2]}>
+                <BellOutlined style={{ fontSize: 18 }} />
               </Badge>
-              <span className="ml-1">消息</span>
             </div>
           </Popover>
 
-          {/* 用户下拉菜单 */}
-          <Dropdown
-            menu={{
-              items: userMenuItems,
-              onClick: handleUserMenuClick,
-            }}
-            placement="bottomRight"
-          >
-            <div className="user-info">
-              <Avatar size={32} icon={<UserOutlined />} src={getUserAvatarUrl()} />
-              <span className="username">{user?.nickname || user?.username || 'User'}</span>
-            </div>
-          </Dropdown>
         </Space>
       </div>
     </Header>
   )
 }
 
-export default AppHeader
+export default AppHeader
\ No newline at end of file
diff --git a/frontend/src/components/MainLayout/AppSider.jsx b/frontend/src/components/MainLayout/AppSider.jsx
index bfb8939..33da543 100644
--- a/frontend/src/components/MainLayout/AppSider.jsx
+++ b/frontend/src/components/MainLayout/AppSider.jsx
@@ -1,5 +1,4 @@
 import { useState, useEffect } from 'react'
-import { Layout, Menu, Badge, message } from 'antd'
 import { useNavigate, useLocation } from 'react-router-dom'
 import {
   DashboardOutlined,
@@ -14,34 +13,40 @@ import {
   FileTextOutlined,
   SafetyOutlined,
   TeamOutlined,
+  ProjectOutlined,
+  RocketOutlined,
+  ReadOutlined,
+  BookOutlined,
 } from '@ant-design/icons'
+import { message } from 'antd'
 import { getUserMenus } from '@/api/menu'
-import './AppSider.css'
-
-const { Sider } = Layout
+import useUserStore from '@/stores/userStore'
+import ModernSidebar from '../ModernSidebar/ModernSidebar'
 
 // 图标映射
 const iconMap = {
-  DashboardOutlined,
-  DesktopOutlined,
-  GlobalOutlined,
-  CloudServerOutlined,
-  UserOutlined,
-  AppstoreOutlined,
-  SettingOutlined,
-  BlockOutlined,
-  FolderOutlined,
-  FileTextOutlined,
-  SafetyOutlined,
-  TeamOutlined,
+  DashboardOutlined: <DashboardOutlined />,
+  DesktopOutlined: <DesktopOutlined />,
+  GlobalOutlined: <GlobalOutlined />,
+  CloudServerOutlined: <CloudServerOutlined />,
+  UserOutlined: <UserOutlined />,
+  AppstoreOutlined: <AppstoreOutlined />,
+  SettingOutlined: <SettingOutlined />,
+  BlockOutlined: <BlockOutlined />,
+  FolderOutlined: <FolderOutlined />,
+  FileTextOutlined: <FileTextOutlined />,
+  SafetyOutlined: <SafetyOutlined />,
+  TeamOutlined: <TeamOutlined />,
+  ProjectOutlined: <ProjectOutlined />,
+  ReadOutlined: <ReadOutlined />,
+  BookOutlined: <BookOutlined />,
 }
 
 function AppSider({ collapsed, onToggle }) {
   const navigate = useNavigate()
   const location = useLocation()
-  const [openKeys, setOpenKeys] = useState([])
-  const [menuData, setMenuData] = useState([])
-  const [loading, setLoading] = useState(true)
+  const { user, logout } = useUserStore()
+  const [menuGroups, setMenuGroups] = useState([])
 
   // 加载菜单数据
   useEffect(() => {
@@ -52,120 +57,137 @@ function AppSider({ collapsed, onToggle }) {
     try {
       const res = await getUserMenus()
       if (res.data) {
-        setMenuData(res.data)
+        // 过滤菜单：只显示 type=1 (目录) 和 type=2 (菜单)
+        const validMenus = res.data.filter(item => [1, 2].includes(item.menu_type))
+        transformMenuData(validMenus)
       }
     } catch (error) {
       console.error('Load menus error:', error)
       message.error('加载菜单失败')
-    } finally {
-      setLoading(false)
     }
   }
 
-  // 根据当前路径获取应该打开的父菜单
-  const getDefaultOpenKeys = () => {
+  const transformMenuData = (data) => {
+    const groups = []
+    
+    // 默认组 (用于存放一级菜单即是叶子节点的情况)
+    const defaultGroup = {
+      title: '', // 空标题或 '通用'
+      items: []
+    }
+
+    data.forEach(item => {
+      // 检查是否有子菜单
+      const validChildren = item.children ? item.children.filter(child => [1, 2].includes(child.menu_type)) : []
+      
+      if (validChildren.length > 0) {
+        // 一级菜单作为组标题
+        const groupItems = validChildren.map(child => {
+          const icon = typeof child.icon === 'string' ? (iconMap[child.icon] || <AppstoreOutlined />) : child.icon
+          return {
+            key: child.menu_code,
+            label: child.menu_name,
+            icon: icon,
+            path: child.path
+          }
+        })
+        
+        groups.push({
+          title: item.menu_name, // e.g. "系统管理"
+          items: groupItems
+        })
+      } else {
+        // 一级菜单是叶子节点，放入默认组
+        const icon = typeof item.icon === 'string' ? (iconMap[item.icon] || <AppstoreOutlined />) : item.icon
+        defaultGroup.items.push({
+          key: item.menu_code,
+          label: item.menu_name,
+          icon: icon,
+          path: item.path
+        })
+      }
+    })
+
+    // 如果默认组有内容，放在最前面
+    if (defaultGroup.items.length > 0) {
+      groups.unshift(defaultGroup)
+    }
+
+    setMenuGroups(groups)
+  }
+
+  const handleNavigate = (key, item) => {
+    if (item.path) {
+      navigate(item.path)
+    }
+  }
+
+  const handleLogout = () => {
+    logout()
+    navigate('/login')
+  }
+  
+  const handleProfileClick = () => {
+    navigate('/profile')
+  }
+
+  // 获取当前激活的 key
+  // 简单匹配 path
+  const getActiveKey = () => {
     const path = location.pathname
-    for (const item of menuData) {
-      if (item.children) {
-        const hasChild = item.children.some((c) => c.path === path)
-        if (hasChild) {
-          return [item.menu_code]
-        }
-      }
-    }
-    return []
-  }
-
-  // 监听菜单数据加载完成，初始化打开的父菜单
-  useEffect(() => {
-    if (menuData.length > 0 && openKeys.length === 0) {
-      const defaultKeys = getDefaultOpenKeys()
-      setOpenKeys(defaultKeys)
-    }
-  }, [menuData])
-
-  const handleMenuClick = ({ key }) => {
-    // 查找对应的路径
-    for (const item of menuData) {
-      if (item.menu_code === key && item.path) {
-        navigate(item.path)
-        return
-      }
-      if (item.children) {
-        const child = item.children.find((c) => c.menu_code === key)
-        if (child && child.path) {
-          navigate(child.path)
-          return
-        }
-      }
-    }
-  }
-
-  const handleOpenChange = (keys) => {
-    setOpenKeys(keys)
-  }
-
-  // 获取当前选中的菜单项
-  const getSelectedKey = () => {
-    const path = location.pathname
-    for (const item of menuData) {
-      if (item.path === path) return item.menu_code
-      if (item.children) {
-        const child = item.children.find((c) => c.path === path)
-        if (child) return child.menu_code
+    // 遍历所有 items 找匹配
+    for (const group of menuGroups) {
+      for (const item of group.items) {
+        if (item.path === path) return item.key
       }
     }
     return ''
   }
 
-  // 生成菜单项配置
-  const getMenuItems = () => {
-    return menuData.map((item) => {
-      const IconComponent = iconMap[item.icon]
-      const icon = IconComponent ? <IconComponent /> : null
+  const logoNode = (
+    <div style={{ display: 'flex', alignItems: 'center', gap: 12, paddingLeft: 8 }}>
+      <img src="/favicon.svg" alt="logo" style={{ width: 32, height: 32 }} />
+      {!collapsed && (
+        <span style={{ fontSize: 18, fontWeight: 'bold', color: '#111' }}>NexDocus</span>
+      )}
+    </div>
+  )
 
-      // 如果有子菜单
-      if (item.children && item.children.length > 0) {
-        return {
-          key: item.menu_code,
-          icon: icon,
-          label: item.menu_name,
-          popupClassName: 'sider-submenu-popup',
-          children: item.children.map((child) => ({
-            key: child.menu_code,
-            label: child.menu_name,
-          })),
-        }
-      }
-
-      // 普通菜单项
-      return {
-        key: item.menu_code,
-        icon: icon,
-        label: item.menu_name,
-      }
-    })
+  // 获取用户头像URL
+  const getUserAvatarUrl = () => {
+    if (!user?.avatar) return null
+    // avatar 字段存储的是相对路径，如：2/avatar/xxx.jpg
+    // 需要转换为 API 端点: /api/v1/auth/avatar/{user_id}/{filename}
+    // 如果已经是 http 开头（第三方），则直接返回
+    if (user.avatar.startsWith('http')) return user.avatar
+    
+    const parts = user.avatar.split('/')
+    if (parts.length >= 3) {
+      const userId = parts[0]
+      const filename = parts[2]
+      return `/api/v1/auth/avatar/${userId}/${filename}`
+    }
+    return null
   }
 
+  const userObj = user ? {
+    name: user.nickname || user.username,
+    role: user.role_name || 'Admin',
+    avatar: getUserAvatarUrl()
+  } : null
+
   return (
-    <Sider
-      className="app-sider"
+    <ModernSidebar
+      logo={logoNode}
+      menuGroups={menuGroups}
+      activeKey={getActiveKey()}
+      onNavigate={handleNavigate}
+      user={userObj}
+      onLogout={handleLogout}
+      onProfileClick={handleProfileClick}
       collapsed={collapsed}
-      width={200}
-      collapsedWidth={64}
-      trigger={null}
-    >
-      {/* 菜单 */}
-      <Menu
-        mode="inline"
-        selectedKeys={[getSelectedKey()]}
-        openKeys={collapsed ? [] : openKeys}
-        onOpenChange={handleOpenChange}
-        onClick={handleMenuClick}
-        className="sider-menu"
-        items={getMenuItems()}
-      />
-    </Sider>
+      onCollapse={onToggle}
+    />
   )
 }
 
diff --git a/frontend/src/components/MainLayout/MainLayout.css b/frontend/src/components/MainLayout/MainLayout.css
index c79a46a..e71ef55 100644
--- a/frontend/src/components/MainLayout/MainLayout.css
+++ b/frontend/src/components/MainLayout/MainLayout.css
@@ -1,24 +1,27 @@
 .main-layout {
   min-height: 100vh;
   display: flex;
-  flex-direction: column;
-  background: #fafafa;
+  flex-direction: row; /* Changed to row for Sider-Left layout */
+  background: var(--bg-color-secondary);
 }
 
 .main-content-wrapper {
   display: flex;
+  flex-direction: column;
   flex: 1;
-  height: calc(100vh - 64px);
-  background: #fafafa;
+  height: 100vh;
+  background: var(--bg-color-secondary);
+  overflow: hidden;
 }
 
 .main-content {
-  background: #f5f5f5;
+  background: var(--bg-color-secondary);
   overflow-y: auto;
   flex: 1;
+  padding: 16px;
 }
 
 .content-wrapper {
-  padding: 8px;
+  padding: 0;
   min-height: 100%;
-}
+}
\ No newline at end of file
diff --git a/frontend/src/components/MainLayout/MainLayout.jsx b/frontend/src/components/MainLayout/MainLayout.jsx
index 2c4ea0b..726c328 100644
--- a/frontend/src/components/MainLayout/MainLayout.jsx
+++ b/frontend/src/components/MainLayout/MainLayout.jsx
@@ -14,10 +14,10 @@ function MainLayout({ children }) {
   }
 
   return (
-    <Layout className="main-layout">
-      <AppHeader collapsed={collapsed} onToggle={toggleCollapsed} />
+    <Layout className="main-layout" hasSider>
+      <AppSider collapsed={collapsed} onToggle={toggleCollapsed} />
       <Layout className="main-content-wrapper">
-        <AppSider collapsed={collapsed} onToggle={toggleCollapsed} />
+        <AppHeader collapsed={collapsed} onToggle={toggleCollapsed} showLogo={false} />
         <Content className="main-content">
           <div className="content-wrapper">
             {children}
diff --git a/frontend/src/components/ModernSidebar/ModernSidebar.css b/frontend/src/components/ModernSidebar/ModernSidebar.css
new file mode 100644
index 0000000..b22ec6b
--- /dev/null
+++ b/frontend/src/components/ModernSidebar/ModernSidebar.css
@@ -0,0 +1,221 @@
+.modern-sidebar {
+  height: 100vh;
+  position: relative;
+  background: var(--sider-bg) !important;
+  border-right: 1px solid var(--border-color);
+  display: flex;
+  flex-direction: column;
+}
+
+.modern-sidebar .ant-layout-sider-children {
+  display: flex;
+  flex-direction: column;
+  height: 100%;
+}
+
+/* Header */
+.modern-sidebar-header {
+  padding: 24px 20px;
+  position: relative;
+  display: flex;
+  align-items: center;
+  height: 80px;
+  flex-shrink: 0;
+}
+
+.logo-container {
+  display: flex;
+  align-items: center;
+  overflow: hidden;
+  white-space: nowrap;
+}
+
+/* Collapse Trigger */
+.collapse-trigger {
+  position: absolute;
+  right: -12px;
+  top: 32px;
+  width: 24px;
+  height: 24px;
+  background: var(--bg-color);
+  border: 1px solid var(--border-color);
+  border-radius: 50%;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  cursor: pointer;
+  z-index: 10;
+  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
+  color: var(--text-color-secondary);
+  transition: all 0.3s;
+}
+
+.collapse-trigger:hover {
+  color: #1677ff;
+  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
+}
+
+/* Menu Area */
+.modern-sidebar-menu {
+  flex: 1;
+  overflow-y: auto;
+  padding: 0 16px;
+}
+
+.modern-sidebar-menu::-webkit-scrollbar {
+  width: 4px;
+}
+
+.modern-sidebar-menu::-webkit-scrollbar-thumb {
+  background: var(--border-color);
+  border-radius: 2px;
+}
+
+/* Menu Group */
+.menu-group {
+  margin-bottom: 24px;
+}
+
+.group-title {
+  font-size: 12px;
+  color: var(--text-color-secondary);
+  font-weight: 600;
+  letter-spacing: 0.5px;
+  margin-bottom: 12px;
+  padding-left: 12px;
+  text-transform: uppercase;
+}
+
+/* Menu Item */
+.modern-sidebar-item {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 12px 16px;
+  margin-bottom: 8px;
+  cursor: pointer;
+  border-radius: 12px; /* Rounded corners */
+  transition: all 0.2s;
+  color: var(--text-color);
+  font-weight: 500;
+}
+
+.modern-sidebar-item:hover {
+  background-color: var(--item-hover-bg);
+  color: var(--text-color);
+}
+
+.modern-sidebar-item.active {
+  background-color: #2563eb; /* Royal Blue */
+  color: #fff;
+  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
+}
+
+.item-content {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+}
+
+.item-icon {
+  font-size: 18px;
+  display: flex;
+  align-items: center;
+}
+
+.item-label {
+  font-size: 14px;
+}
+
+.item-arrow {
+  font-size: 12px;
+  opacity: 0.8;
+}
+
+/* Collapsed State */
+.modern-sidebar-item.collapsed {
+  justify-content: center;
+  padding: 12px;
+  border-radius: 12px;
+}
+
+/* Footer */
+.modern-sidebar-footer {
+  padding: 16px;
+  flex-shrink: 0;
+  background: var(--sider-bg);
+}
+
+.footer-link {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  color: var(--text-color-secondary);
+  font-size: 14px;
+  margin-bottom: 16px;
+  padding-left: 12px;
+  cursor: pointer;
+  transition: color 0.2s;
+}
+
+.footer-link:hover {
+  color: var(--text-color);
+}
+
+.footer-link.collapsed {
+  justify-content: center;
+  padding-left: 0;
+}
+
+/* User Card */
+.user-card {
+  background-color: var(--bg-color-secondary); /* Light gray background */
+  border-radius: 12px;
+  padding: 12px;
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  transition: all 0.2s;
+}
+
+.user-info {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  overflow: hidden;
+}
+
+.user-details {
+  display: flex;
+  flex-direction: column;
+  overflow: hidden;
+}
+
+.user-name {
+  font-size: 14px;
+  font-weight: 600;
+  color: var(--text-color);
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
+
+.user-role {
+  font-size: 12px;
+  color: var(--text-color-secondary);
+  text-transform: uppercase;
+  font-weight: 500;
+}
+
+.logout-btn {
+  color: var(--text-color-secondary);
+  cursor: pointer;
+  padding: 4px;
+  border-radius: 4px;
+  transition: all 0.2s;
+}
+
+.logout-btn:hover {
+  background-color: var(--border-color);
+  color: #ef4444; /* Red for logout */
+}
\ No newline at end of file
diff --git a/frontend/src/components/ModernSidebar/ModernSidebar.jsx b/frontend/src/components/ModernSidebar/ModernSidebar.jsx
new file mode 100644
index 0000000..d4ce841
--- /dev/null
+++ b/frontend/src/components/ModernSidebar/ModernSidebar.jsx
@@ -0,0 +1,154 @@
+import React, { useState } from 'react';
+import { Layout, Avatar, Tooltip, Button } from 'antd';
+import {
+  MenuUnfoldOutlined,
+  MenuFoldOutlined,
+  LogoutOutlined,
+  QuestionCircleOutlined,
+  RightOutlined,
+  LeftOutlined
+} from '@ant-design/icons';
+import './ModernSidebar.css';
+
+const { Sider } = Layout;
+
+const ModernSidebar = ({
+  logo,
+  menuGroups = [],
+  activeKey,
+  onNavigate,
+  user,
+  onLogout,
+  onProfileClick,
+  collapsed,
+  onCollapse,
+  width = 260,
+  collapsedWidth = 80,
+  className = '',
+  style = {}
+}) => {
+  
+  const handleItemClick = (item) => {
+    if (onNavigate) {
+      onNavigate(item.key, item);
+    }
+  };
+
+  const renderMenuItem = (item) => {
+    const isActive = activeKey === item.key;
+    
+    // 如果是折叠状态，只显示图标，并使用Tooltip
+    if (collapsed) {
+      return (
+        <Tooltip title={item.label} placement="right" key={item.key}>
+          <div 
+            className={`modern-sidebar-item collapsed ${isActive ? 'active' : ''}`}
+            onClick={() => handleItemClick(item)}
+          >
+            <div className="item-icon">{item.icon}</div>
+          </div>
+        </Tooltip>
+      );
+    }
+
+    return (
+      <div 
+        key={item.key}
+        className={`modern-sidebar-item ${isActive ? 'active' : ''}`}
+        onClick={() => handleItemClick(item)}
+      >
+        <div className="item-content">
+          <div className="item-icon">{item.icon}</div>
+          <span className="item-label">{item.label}</span>
+        </div>
+        {isActive && <RightOutlined className="item-arrow" />}
+      </div>
+    );
+  };
+
+  return (
+    <Sider
+      width={width}
+      collapsed={collapsed}
+      collapsedWidth={collapsedWidth}
+      trigger={null}
+      className={`modern-sidebar ${className}`}
+      theme="light"
+      style={style}
+    >
+      {/* 顶部 Logo 区域 */}
+      <div className="modern-sidebar-header">
+        <div className="logo-container">
+          {logo}
+        </div>
+        {/* 折叠按钮 - 悬浮在边缘 */}
+        <div 
+          className="collapse-trigger"
+          onClick={() => onCollapse && onCollapse(!collapsed)}
+        >
+          {collapsed ? <RightOutlined /> : <LeftOutlined />}
+        </div>
+      </div>
+
+      {/* 菜单列表区域 */}
+      <div className="modern-sidebar-menu">
+        {menuGroups.map((group, index) => (
+          <div key={index} className="menu-group">
+            {!collapsed && group.title && (
+              <div className="group-title">{group.title}</div>
+            )}
+            <div className="group-items">
+              {group.items.map(item => renderMenuItem(item))}
+            </div>
+          </div>
+        ))}
+      </div>
+
+      {/* 底部区域 */}
+      <div className="modern-sidebar-footer">
+        {/* 帮助支持 */}
+        {!collapsed && (
+          <div className="footer-link">
+            <QuestionCircleOutlined />
+            <span>帮助支持</span>
+          </div>
+        )}
+        {collapsed && (
+           <div className="footer-link collapsed">
+             <QuestionCircleOutlined />
+           </div>
+        )}
+
+        {/* 用户卡片 */}
+        <div className="user-card">
+          <div 
+            className="user-info" 
+            onClick={onProfileClick}
+            style={{ cursor: onProfileClick ? 'pointer' : 'default' }}
+          >
+            <Avatar 
+              size={collapsed ? 32 : 40} 
+              src={user?.avatar} 
+              style={{ backgroundColor: '#1677ff' }}
+            >
+              {user?.name?.[0]?.toUpperCase() || 'U'}
+            </Avatar>
+            {!collapsed && (
+              <div className="user-details">
+                <div className="user-name">{user?.name || 'User'}</div>
+                <div className="user-role">{user?.role || 'Member'}</div>
+              </div>
+            )}
+          </div>
+          {!collapsed && (
+            <div className="logout-btn" onClick={onLogout} title="退出登录">
+              <LogoutOutlined />
+            </div>
+          )}
+        </div>
+      </div>
+    </Sider>
+  );
+};
+
+export default ModernSidebar;
diff --git a/frontend/src/index.css b/frontend/src/index.css
index b0435a7..bfa1d8f 100644
--- a/frontend/src/index.css
+++ b/frontend/src/index.css
@@ -1,3 +1,32 @@
+:root {
+  --bg-color: #fff;
+  --bg-color-secondary: #fafafa;
+  --text-color: #000000e0;
+  --text-color-secondary: #00000073;
+  --border-color: #f0f0f0;
+  --header-bg: #fff;
+  --sider-bg: #fff;
+  --item-hover-bg: #f5f5f5;
+  --card-bg: #fff;
+}
+
+body.dark {
+  --bg-color: #141414;
+  --bg-color-secondary: #1f1f1f;
+  --text-color: #ffffffd9;
+  --text-color-secondary: #ffffff73;
+  --border-color: #303030;
+  --header-bg: #141414;
+  --sider-bg: #141414;
+  --item-hover-bg: #1f1f1f;
+  --card-bg: #1f1f1f;
+}
+
+body {
+  background-color: var(--bg-color);
+  color: var(--text-color);
+}
+
 .search-highlight {
   background-color: #ffd54f !important;
   color: black !important;
diff --git a/frontend/src/stores/themeStore.js b/frontend/src/stores/themeStore.js
new file mode 100644
index 0000000..8c7a6cd
--- /dev/null
+++ b/frontend/src/stores/themeStore.js
@@ -0,0 +1,17 @@
+import { create } from 'zustand'
+import { persist, createJSONStorage } from 'zustand/middleware'
+
+const useThemeStore = create(
+  persist(
+    (set) => ({
+      isDarkMode: false,
+      toggleTheme: () => set((state) => ({ isDarkMode: !state.isDarkMode })),
+    }),
+    {
+      name: 'theme-storage',
+      storage: createJSONStorage(() => localStorage),
+    }
+  )
+)
+
+export default useThemeStore
diff --git a/frontend/src/stores/userStore.js b/frontend/src/stores/userStore.js
index b132ed2..a98f69d 100644
--- a/frontend/src/stores/userStore.js
+++ b/frontend/src/stores/userStore.js
@@ -2,7 +2,7 @@
  * 用户状态管理 Store
  */
 import { create } from 'zustand'
-import { persist } from 'zustand/middleware'
+import { persist, createJSONStorage } from 'zustand/middleware'
 
 const useUserStore = create(
   persist(
@@ -26,7 +26,7 @@ const useUserStore = create(
     }),
     {
       name: 'user-storage',
-      getStorage: () => localStorage,
+      storage: createJSONStorage(() => localStorage),
     }
   )
 )