diff --git a/client/src/App.jsx b/client/src/App.jsx
index 19bc46a..5c3a733 100644
--- a/client/src/App.jsx
+++ b/client/src/App.jsx
@@ -1,5 +1,5 @@
 import React, { useState, useEffect } from 'react'
-import { Layout, Menu, theme, Button, Space, Dropdown, message, Drawer, Avatar, Modal, Form, Input, Badge, Tooltip } from 'antd'
+import { Layout, Menu, theme, ConfigProvider, Button, Space, Dropdown, message, Drawer, Avatar, Modal, Form, Input, Badge, Tooltip } from 'antd'
 import {
   DashboardOutlined,
   DesktopOutlined,
@@ -13,13 +13,17 @@ import {
   DownOutlined,
   UserSwitchOutlined,
   KeyOutlined,
-  MessageOutlined
+  MessageOutlined,
+  MoonOutlined,
+  SunOutlined,
+  SwapOutlined
 } from '@ant-design/icons'
 import axios from 'axios'
 import Login from './pages/Login'
 import Weather from './components/Weather'
 import Dashboard from './pages/Dashboard'
 import DeviceManagement from './pages/DeviceManagement'
+import DeviceLoan from './pages/DeviceLoan'
 import PersonnelManagement from './pages/PersonnelManagement'
 import NotificationManagement from './pages/NotificationManagement'
 import AccountManagement from './pages/AccountManagement'
@@ -41,8 +45,36 @@ function useIsMobile() {
   return isMobile
 }
 
+// 深色模式 Hook：优先用户手动选择（localStorage），否则跟随系统 prefers-color-scheme
+function useThemeMode() {
+  const [mode, setMode] = useState(() => localStorage.getItem('themeMode') || 'auto')
+  const [sysDark, setSysDark] = useState(() => window.matchMedia('(prefers-color-scheme: dark)').matches)
+  useEffect(() => {
+    const mq = window.matchMedia('(prefers-color-scheme: dark)')
+    const onChange = (e) => setSysDark(e.matches)
+    if (mq.addEventListener) mq.addEventListener('change', onChange)
+    else mq.addListener(onChange)
+    return () => {
+      if (mq.removeEventListener) mq.removeEventListener('change', onChange)
+      else mq.removeListener(onChange)
+    }
+  }, [])
+  const isDark = mode === 'dark' || (mode === 'auto' && sysDark)
+  useEffect(() => {
+    // 供 index.css 中 [data-theme='dark'] 变量覆盖使用
+    document.documentElement.setAttribute('data-theme', isDark ? 'dark' : 'light')
+  }, [isDark])
+  const toggle = () => {
+    const next = isDark ? 'light' : 'dark'
+    setMode(next)
+    localStorage.setItem('themeMode', next)
+  }
+  return { isDark, toggle }
+}
+
 function App() {
   const isMobile = useIsMobile()
+  const { isDark, toggle: toggleTheme } = useThemeMode()
   const [collapsed, setCollapsed] = useState(false)
   const [drawerVisible, setDrawerVisible] = useState(false)
   const [currentPage, setCurrentPage] = useState('dashboard')
@@ -124,6 +156,7 @@ function App() {
     { key: 'dashboard', icon: <DashboardOutlined />, label: '系统首页' },
     { type: 'divider' },
     { key: 'devices', icon: <DesktopOutlined />, label: '设备管理' },
+    { key: 'loans', icon: <SwapOutlined />, label: '设备借用' },
     { key: 'personnel', icon: <TeamOutlined />, label: '人员管理' },
     ...(user?.role === 'admin' ? [{ key: 'accounts', icon: <UserSwitchOutlined />, label: '账户管理' }] : []),
     { key: 'notifications', icon: <BellOutlined />, label: '通知管理' },
@@ -146,6 +179,7 @@ function App() {
       case 'about': return <About />
       case 'guide': return <Guide />
       case 'devices': return <DeviceManagement user={user} />
+      case 'loans': return <DeviceLoan user={user} />
       case 'personnel': return <PersonnelManagement user={user} />
       case 'accounts': return user?.role === 'admin' ? <AccountManagement user={user} /> : <Dashboard onNavigate={setCurrentPage} />
       case 'notifications': return <NotificationManagement user={user} />
@@ -157,7 +191,7 @@ function App() {
   const getPageTitle = () => {
     const titles = {
       dashboard: '系统首页', about: '软件简介', guide: '使用说明',
-      devices: '设备管理', personnel: '人员管理', accounts: '账户管理',
+      devices: '设备管理', loans: '设备借用', personnel: '人员管理', accounts: '账户管理',
       notifications: '通知管理', messages: '消息对话'
     }
     return titles[currentPage] || '系统首页'
@@ -240,8 +274,15 @@ function App() {
     return <div style={{ height: '100vh', display: 'flex', alignItems: 'center', justifyContent: 'center' }}>加载中...</div>
   }
 
+  // antd 主题：深色/浅色算法切换；登录页固定浅色（白卡片渐变背景）
+  const antdTheme = { algorithm: isDark ? theme.darkAlgorithm : theme.defaultAlgorithm }
+
   if (!user) {
-    return <Login onLogin={handleLogin} />
+    return (
+      <ConfigProvider theme={{ algorithm: theme.defaultAlgorithm }}>
+        <Login onLogin={handleLogin} />
+      </ConfigProvider>
+    )
   }
 
   const menuContent = (
@@ -262,13 +303,17 @@ function App() {
   // ============ 移动端布局 ============
   if (isMobile) {
     return (
+      <ConfigProvider theme={antdTheme}>
       <Layout style={{ minHeight: '100vh' }}>
         <Header className="mobile-header">
           <Button type="text" icon={<MenuOutlined />} onClick={() => setDrawerVisible(true)} style={{ color: '#fff' }} />
           <span className="mobile-title">{getPageTitle()}</span>
-          <Dropdown menu={{ items: userMenuItems }} placement="bottomRight" trigger={['click']}>
-            <Avatar style={{ backgroundColor: '#7c3aed' }} icon={<UserOutlined />} />
-          </Dropdown>
+          <Space size={4}>
+            <Button type="text" icon={isDark ? <SunOutlined /> : <MoonOutlined />} onClick={toggleTheme} style={{ color: '#fff' }} />
+            <Dropdown menu={{ items: userMenuItems }} placement="bottomRight" trigger={['click']}>
+              <Avatar style={{ backgroundColor: '#7c3aed' }} icon={<UserOutlined />} />
+            </Dropdown>
+          </Space>
         </Header>
 
         <div className="mobile-info-bar">
@@ -306,11 +351,13 @@ function App() {
         {pwdModal}
         <PushService user={user} />
       </Layout>
+      </ConfigProvider>
     )
   }
 
   // ============ 桌面端布局 ============
   return (
+    <ConfigProvider theme={antdTheme}>
     <Layout style={{ minHeight: '100vh' }}>
       <Sider trigger={null} collapsible collapsed={collapsed} theme="dark">
         <div className="logo-area">
@@ -349,6 +396,9 @@ function App() {
           <Space size="large" align="center">
             <Weather />
             <div className="greeting-text">{user.display_name || user.username}，{getGreeting()}！</div>
+            <Tooltip title={isDark ? '切换浅色模式' : '切换深色模式'}>
+              <Button type="text" icon={isDark ? <SunOutlined /> : <MoonOutlined />} onClick={toggleTheme} />
+            </Tooltip>
             <Button type="text" icon={<KeyOutlined />} onClick={() => setPwdModalVisible(true)}>
               修改密码
             </Button>
@@ -368,6 +418,7 @@ function App() {
       {pwdModal}
       <PushService user={user} />
     </Layout>
+    </ConfigProvider>
   )
 }
 
diff --git a/client/src/index.css b/client/src/index.css
index dfd6676..8fb79cf 100644
--- a/client/src/index.css
+++ b/client/src/index.css
@@ -4,8 +4,47 @@
   box-sizing: border-box;
 }
 
+/* ==================== 主题变量（深色模式适配） ==================== */
+:root {
+  --page-bg: #f5f7fa;
+  --card-bg: #ffffff;
+  --text-main: #374151;
+  --text-sub: #666666;
+  --text-hint: #999999;
+  --text-faint: #bbbbbb;
+  --border: #e8e8e8;
+  --border-light: #f0f0f0;
+  --hover-bg: #f5f5f5;
+  --active-bg: #f0ebff;
+  --chat-bg: #fafafa;
+  --tip-bg: #e6f7ff;
+  --tip-border: #91d5ff;
+  --warn-bg: #fffbe6;
+  --warn-border: #ffe58f;
+}
+
+[data-theme='dark'] {
+  --page-bg: #141414;
+  --card-bg: #1f1f1f;
+  --text-main: rgba(255, 255, 255, 0.85);
+  --text-sub: rgba(255, 255, 255, 0.65);
+  --text-hint: rgba(255, 255, 255, 0.45);
+  --text-faint: rgba(255, 255, 255, 0.3);
+  --border: #303030;
+  --border-light: #303030;
+  --hover-bg: #2a2a2a;
+  --active-bg: #2a2140;
+  --chat-bg: #181818;
+  --tip-bg: #111a2c;
+  --tip-border: #153450;
+  --warn-bg: #2b2111;
+  --warn-border: #594214;
+}
+
 body {
   font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
+  background: var(--page-bg);
+  color: var(--text-main);
 }
 
 .logo {
@@ -79,12 +118,12 @@ body {
 .about-page h2 {
   font-size: 20px;
   margin: 24px 0 12px;
-  color: #333;
+  color: var(--text-main);
 }
 
 .about-page p {
   line-height: 1.8;
-  color: #666;
+  color: var(--text-sub);
   margin-bottom: 12px;
 }
 
@@ -95,7 +134,7 @@ body {
 
 .about-page li {
   line-height: 2;
-  color: #666;
+  color: var(--text-sub);
 }
 
 .guide-page {
@@ -113,20 +152,20 @@ body {
 .guide-page h2 {
   font-size: 20px;
   margin: 24px 0 12px;
-  color: #333;
+  color: var(--text-main);
   padding-bottom: 8px;
-  border-bottom: 2px solid #e8e8e8;
+  border-bottom: 2px solid var(--border);
 }
 
 .guide-page h3 {
   font-size: 16px;
   margin: 16px 0 8px;
-  color: #444;
+  color: var(--text-main);
 }
 
 .guide-page p {
   line-height: 1.8;
-  color: #666;
+  color: var(--text-sub);
   margin-bottom: 12px;
 }
 
@@ -138,20 +177,20 @@ body {
 
 .guide-page li {
   line-height: 2;
-  color: #666;
+  color: var(--text-sub);
 }
 
 .guide-page .tip {
-  background: #e6f7ff;
-  border: 1px solid #91d5ff;
+  background: var(--tip-bg);
+  border: 1px solid var(--tip-border);
   border-radius: 4px;
   padding: 12px 16px;
   margin: 12px 0;
 }
 
 .guide-page .warning {
-  background: #fffbe6;
-  border: 1px solid #ffe58f;
+  background: var(--warn-bg);
+  border: 1px solid var(--warn-border);
   border-radius: 4px;
   padding: 12px 16px;
   margin: 12px 0;
@@ -315,7 +354,7 @@ body {
 /* ==================== 顶部问候语 ==================== */
 .greeting-text {
   font-size: 15px;
-  color: #374151;
+  color: var(--text-main);
   font-weight: 500;
 }
 
@@ -351,21 +390,21 @@ body {
   justify-content: space-between;
   gap: 8px;
   padding: 10px 12px;
-  background: #f5f7fa;
-  border-bottom: 1px solid #e8e8e8;
+  background: var(--page-bg);
+  border-bottom: 1px solid var(--border);
   flex-wrap: wrap;
 }
 
 .mobile-greeting {
   font-size: 14px;
-  color: #374151;
+  color: var(--text-main);
   font-weight: 500;
 }
 
 .mobile-content {
   padding: 12px;
   padding-bottom: 76px; /* 为底部导航留空间 */
-  background: #f5f7fa;
+  background: var(--page-bg);
 }
 
 /* 底部导航 */
@@ -375,8 +414,8 @@ body {
   left: 0;
   right: 0;
   display: flex;
-  background: #fff;
-  border-top: 1px solid #e8e8e8;
+  background: var(--card-bg);
+  border-top: 1px solid var(--border);
   z-index: 100;
   padding-bottom: env(safe-area-inset-bottom);
 }
@@ -391,7 +430,7 @@ body {
   padding: 8px 0;
   border: none;
   background: none;
-  color: #8c8c8c;
+  color: var(--text-hint);
   font-size: 12px;
   cursor: pointer;
   transition: color 0.2s;
@@ -527,7 +566,7 @@ body {
 
 .messages-list {
   width: 320px;
-  border-right: 1px solid #f0f0f0;
+  border-right: 1px solid var(--border-light);
   padding: 12px;
   overflow-y: auto;
 }
@@ -540,13 +579,13 @@ body {
 }
 
 .conv-item:hover {
-  background: #f5f5f5;
+  background: var(--hover-bg);
   border-radius: 6px;
 }
 
 .conv-item-active,
 .conv-item-active:hover {
-  background: #f0ebff;
+  background: var(--active-bg);
   border-radius: 6px;
 }
 
@@ -560,14 +599,14 @@ body {
   display: flex;
   align-items: center;
   padding: 12px 16px;
-  border-bottom: 1px solid #f0f0f0;
+  border-bottom: 1px solid var(--border-light);
 }
 
 .chat-messages {
   flex: 1;
   overflow-y: auto;
   padding: 16px;
-  background: #fafafa;
+  background: var(--chat-bg);
 }
 
 .chat-msg {
@@ -583,15 +622,15 @@ body {
 
 .chat-msg-sender {
   font-size: 12px;
-  color: #999;
+  color: var(--text-hint);
   margin-bottom: 3px;
 }
 
 .chat-bubble {
   max-width: 70%;
   padding: 8px 12px;
-  background: #fff;
-  border: 1px solid #eee;
+  background: var(--card-bg);
+  border: 1px solid var(--border-light);
   border-radius: 8px;
   white-space: pre-wrap;
   word-break: break-word;
@@ -605,16 +644,104 @@ body {
 
 .chat-msg-time {
   font-size: 11px;
-  color: #bbb;
+  color: var(--text-faint);
   margin-top: 3px;
 }
 
+.chat-msg-status {
+  margin-left: 6px;
+  font-size: 11px;
+  display: inline-flex;
+  align-items: center;
+  gap: 3px;
+  cursor: default;
+}
+
+.chat-msg-read {
+  color: #52c41a;
+}
+
+.chat-msg-unread {
+  color: var(--text-hint);
+}
+
 .chat-input {
+  display: flex;
+  flex-direction: column;
+  gap: 6px;
+  padding: 8px 16px 12px;
+  border-top: 1px solid var(--border-light);
+}
+
+.chat-toolbar {
+  display: flex;
+  gap: 2px;
+}
+
+.chat-input-row {
   display: flex;
   gap: 8px;
   align-items: flex-end;
-  padding: 12px 16px;
-  border-top: 1px solid #f0f0f0;
+}
+
+.emoji-panel {
+  display: grid;
+  grid-template-columns: repeat(8, 1fr);
+  gap: 2px;
+  max-width: 320px;
+}
+
+.emoji-item {
+  font-size: 20px;
+  line-height: 1;
+  padding: 5px;
+  border-radius: 6px;
+  cursor: pointer;
+  text-align: center;
+}
+
+.emoji-item:hover {
+  background: var(--hover-bg);
+}
+
+.chat-bubble-media {
+  background: var(--card-bg);
+  border: 1px solid var(--border-light);
+  color: inherit;
+  padding: 4px;
+}
+
+.chat-file-card {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  min-width: 200px;
+  max-width: 280px;
+  padding: 10px 12px;
+}
+
+.chat-file-info {
+  flex: 1;
+  min-width: 0;
+}
+
+.chat-file-name {
+  font-size: 13px;
+  color: var(--text-main);
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.chat-file-size {
+  font-size: 12px;
+  color: var(--text-hint);
+}
+
+.chat-file-download {
+  color: #7c3aed;
+  font-size: 16px;
+  padding: 4px;
 }
 
 .chat-placeholder {
diff --git a/client/src/pages/About.jsx b/client/src/pages/About.jsx
index 5803afd..7fe2877 100644
--- a/client/src/pages/About.jsx
+++ b/client/src/pages/About.jsx
@@ -5,7 +5,7 @@ function About() {
   return (
     <div className="about-page">
       <Card>
-        <h1>影视星河 · 设备管理系统 v2.2</h1>
+        <h1>影视星河 · 设备管理系统 v5.0</h1>
         <Divider />
 
         <h2>软件概述</h2>
@@ -19,6 +19,7 @@ function About() {
           <li><strong>登录认证：</strong>支持账号密码登录，内置默认管理员账户，登录后根据时间智能问候</li>
           <li><strong>每日天气：</strong>顶部导航栏实时显示当前城市天气、温度、湿度等信息</li>
           <li><strong>设备管理：</strong>支持设备的添加、编辑、删除、查询等全生命周期管理，涵盖笔记本电脑、台式机、显示器、打印机、网络设备等各类IT资产</li>
+          <li><strong>设备借用：</strong>支持设备借用登记与归还管理，可上传借用/归还照片，从已有设备与人员中选择，服务器自动记录借用与归还时间</li>
           <li><strong>人员管理：</strong>维护组织架构中的人员信息，包括部门、职位、联系方式等，便于设备责任分配</li>
           <li><strong>通知管理：</strong>支持发布各类通知、公告和提醒，可设置优先级和发送范围，确保重要信息及时传达</li>
           <li><strong>数据概览：</strong>提供直观的仪表盘，实时展示设备状态、人员情况和通知统计</li>
@@ -62,12 +63,21 @@ function About() {
 
         <h2>版本信息</h2>
         <ul>
-          <li>当前版本：v2.2</li>
+          <li>当前版本：v5.0</li>
           <li>发布日期：2026年8月</li>
           <li>许可证：MIT License</li>
         </ul>
 
         <h2>更新日志</h2>
+        <h3>v5.0（2026年8月）</h3>
+        <ol>
+          <li>新增设备借用功能：支持上传借用照片，从已有设备中选择借用设备，从已有成员中选择借用人</li>
+          <li>新增设备归还功能：支持上传归还照片，设备与人员可从已有数据中选择</li>
+          <li>服务器自动存储借用时间与归还时间</li>
+          <li>苹果端适配 Liquid Glass 液态玻璃设计（iOS 26/27）</li>
+          <li>优化苹果端退出后台后需重新登录的问题</li>
+          <li>修复苹果端底部导航栏触控困难的问题</li>
+        </ol>
         <h3>v2.2（2026年8月）</h3>
         <ol>
           <li>添加群聊删除人员的功能</li>
diff --git a/client/src/pages/Dashboard.jsx b/client/src/pages/Dashboard.jsx
index 39da754..858b106 100644
--- a/client/src/pages/Dashboard.jsx
+++ b/client/src/pages/Dashboard.jsx
@@ -120,7 +120,7 @@ function Dashboard({ onNavigate }) {
         <h3>系统信息</h3>
         <Row gutter={16} style={{ marginTop: 12 }}>
           <Col span={8}>
-            <p><strong>系统版本：</strong>v2.2</p>
+            <p><strong>系统版本：</strong>v5.0</p>
             <p><strong>系统名称：</strong>设备管理系统</p>
           </Col>
           <Col span={8}>
diff --git a/client/src/pages/DeviceLoan.jsx b/client/src/pages/DeviceLoan.jsx
new file mode 100644
index 0000000..9a4cb24
--- /dev/null
+++ b/client/src/pages/DeviceLoan.jsx
@@ -0,0 +1,346 @@
+import React, { useState, useEffect } from 'react'
+import {
+  Card, Table, Tag, Button, Modal, Form, Select, Upload, Input, Space,
+  Image, message, Empty, Row, Col, Statistic
+} from 'antd'
+import {
+  PlusOutlined, SwapOutlined, CameraOutlined, CheckCircleOutlined, ClockCircleOutlined
+} from '@ant-design/icons'
+import axios from 'axios'
+import { getApiBase } from '../apiConfig'
+
+// 借用/归还照片地址（图片无法携带 Authorization 头，走查询参数 token）
+const photoUrl = (fileId) => {
+  if (!fileId) return ''
+  const token = localStorage.getItem('token') || ''
+  return `${getApiBase()}/api/loans/photo/${fileId}?token=${encodeURIComponent(token)}`
+}
+
+function DeviceLoan({ user }) {
+  const [loans, setLoans] = useState([])
+  const [devices, setDevices] = useState([])
+  const [personnel, setPersonnel] = useState([])
+  const [loading, setLoading] = useState(false)
+  const [statusFilter, setStatusFilter] = useState('')
+  const [keyword, setKeyword] = useState('')
+
+  // 借用弹窗
+  const [loanOpen, setLoanOpen] = useState(false)
+  const [loanForm] = Form.useForm()
+  const [loanPhoto, setLoanPhoto] = useState('')
+  const [loanPhotoPreview, setLoanPhotoPreview] = useState('')
+  const [submitting, setSubmitting] = useState(false)
+
+  // 归还弹窗
+  const [returnOpen, setReturnOpen] = useState(false)
+  const [returnTarget, setReturnTarget] = useState(null)
+  const [returnForm] = Form.useForm()
+  const [returnPhoto, setReturnPhoto] = useState('')
+  const [returnPhotoPreview, setReturnPhotoPreview] = useState('')
+
+  const loadLoans = async () => {
+    setLoading(true)
+    try {
+      const res = await axios.get('/api/loans')
+      if (res.data.success) setLoans(res.data.data || [])
+    } catch (err) {
+      message.error(err.response?.data?.message || '加载借用记录失败')
+    } finally {
+      setLoading(false)
+    }
+  }
+
+  useEffect(() => {
+    loadLoans()
+    axios.get('/api/devices').then(res => {
+      if (res.data.success) setDevices(res.data.data || [])
+    }).catch(() => {})
+    axios.get('/api/personnel').then(res => {
+      if (res.data.success) setPersonnel(res.data.data || [])
+    }).catch(() => {})
+  }, [])
+
+  // 上传照片（复用通用文件上传接口，返回 fileId）
+  const uploadPhoto = async (file) => {
+    const fd = new FormData()
+    fd.append('file', file)
+    const res = await axios.post('/api/chat/upload', fd, {
+      headers: { 'Content-Type': 'multipart/form-data' }
+    })
+    if (!res.data.success) throw new Error(res.data.message || '上传失败')
+    return res.data.data.fileId
+  }
+
+  // ============ 借用 ============
+  const openLoanModal = () => {
+    loanForm.resetFields()
+    setLoanPhoto('')
+    setLoanPhotoPreview('')
+    setLoanOpen(true)
+  }
+
+  const handleLoanPhoto = async (file) => {
+    try {
+      const fileId = await uploadPhoto(file)
+      setLoanPhoto(fileId)
+      setLoanPhotoPreview(photoUrl(fileId))
+      message.success('借用照片上传成功')
+    } catch (err) {
+      message.error(err.response?.data?.message || err.message || '照片上传失败')
+    }
+    return false
+  }
+
+  const submitLoan = async () => {
+    try {
+      const values = await loanForm.validateFields()
+      setSubmitting(true)
+      const res = await axios.post('/api/loans', {
+        device_id: values.device_id,
+        borrower: values.borrower,
+        borrower_id: personnel.find(p => p.name === values.borrower)?.id || '',
+        photo: loanPhoto,
+        remark: values.remark || ''
+      })
+      if (res.data.success) {
+        message.success(res.data.message || '借用成功')
+        setLoanOpen(false)
+        loadLoans()
+      }
+    } catch (err) {
+      if (err.response) message.error(err.response.data?.message || '借用失败')
+    } finally {
+      setSubmitting(false)
+    }
+  }
+
+  // ============ 归还 ============
+  const openReturnModal = (loan) => {
+    setReturnTarget(loan)
+    setReturnPhoto('')
+    setReturnPhotoPreview('')
+    returnForm.setFieldsValue({
+      device_id: loan.device_id,
+      borrower: loan.borrower
+    })
+    setReturnOpen(true)
+  }
+
+  const handleReturnPhoto = async (file) => {
+    try {
+      const fileId = await uploadPhoto(file)
+      setReturnPhoto(fileId)
+      setReturnPhotoPreview(photoUrl(fileId))
+      message.success('归还照片上传成功')
+    } catch (err) {
+      message.error(err.response?.data?.message || err.message || '照片上传失败')
+    }
+    return false
+  }
+
+  const submitReturn = async () => {
+    try {
+      const values = await returnForm.validateFields()
+      setSubmitting(true)
+      const res = await axios.post(`/api/loans/${returnTarget.id}/return`, {
+        device_id: values.device_id,
+        borrower: values.borrower,
+        borrower_id: personnel.find(p => p.name === values.borrower)?.id || '',
+        photo: returnPhoto
+      })
+      if (res.data.success) {
+        message.success(res.data.message || '归还成功')
+        setReturnOpen(false)
+        loadLoans()
+      }
+    } catch (err) {
+      if (err.response) message.error(err.response.data?.message || '归还失败')
+    } finally {
+      setSubmitting(false)
+    }
+  }
+
+  // ============ 列表 ============
+  const filtered = loans.filter(l => {
+    if (statusFilter && l.status !== statusFilter) return false
+    if (keyword) {
+      const k = keyword.toLowerCase()
+      const hit = [l.device_name, l.borrower, l.created_by]
+        .some(v => (v || '').toLowerCase().includes(k))
+      if (!hit) return false
+    }
+    return true
+  })
+
+  const loaning = loans.filter(l => l.status === '借用中').length
+  const returned = loans.filter(l => l.status === '已归还').length
+
+  const columns = [
+    {
+      title: '设备', dataIndex: 'device_name', key: 'device',
+      render: (v) => <strong>{v || '-'}</strong>
+    },
+    {
+      title: '借用人', dataIndex: 'borrower', key: 'borrower',
+      render: (v, r) => {
+        const p = personnel.find(x => x.name === r.borrower)
+        return p ? `${v}（${p.department || '-'}）` : v
+      }
+    },
+    {
+      title: '状态', dataIndex: 'status', key: 'status', width: 100,
+      render: (v) => v === '已归还'
+        ? <Tag color="green">已归还</Tag>
+        : <Tag color="orange">借用中</Tag>
+    },
+    { title: '借用时间', dataIndex: 'loan_time', key: 'loan_time', width: 170 },
+    { title: '归还时间', dataIndex: 'return_time', key: 'return_time', width: 170, render: (v) => v || '-' },
+    {
+      title: '借用照片', dataIndex: 'loan_photo', key: 'loan_photo', width: 90,
+      render: (v) => v
+        ? <Image src={photoUrl(v)} width={56} height={56} style={{ objectFit: 'cover', borderRadius: 6 }} />
+        : <span style={{ color: '#999' }}>-</span>
+    },
+    {
+      title: '归还照片', dataIndex: 'return_photo', key: 'return_photo', width: 90,
+      render: (v) => v
+        ? <Image src={photoUrl(v)} width={56} height={56} style={{ objectFit: 'cover', borderRadius: 6 }} />
+        : <span style={{ color: '#999' }}>-</span>
+    },
+    { title: '经办人', dataIndex: 'created_by', key: 'created_by', width: 110, render: (v) => v || '-' },
+    {
+      title: '操作', key: 'action', width: 100,
+      render: (_, r) => r.status === '借用中'
+        ? <Button type="primary" size="small" icon={<SwapOutlined />} onClick={() => openReturnModal(r)}>归还</Button>
+        : null
+    }
+  ]
+
+  const deviceOptions = devices
+    .filter(d => d.status !== '已报废')
+    .map(d => ({ value: d.id, label: `${d.name}（${d.type || '未分类'} / ${d.status}）` }))
+
+  const personnelOptions = personnel.map(p => ({
+    value: p.name,
+    label: `${p.name}${p.department ? ' · ' + p.department : ''}${p.position ? ' · ' + p.position : ''}`
+  }))
+
+  // 照片上传按钮（借用/归还共用样式）
+  const photoUploadBtn = (preview, beforeUpload, text) => (
+    <Space align="start">
+      <Upload
+        accept="image/*"
+        showUploadList={false}
+        beforeUpload={beforeUpload}
+      >
+        <Button icon={<CameraOutlined />}>{text}</Button>
+      </Upload>
+      {preview && (
+        <Image src={preview} width={64} height={64} style={{ objectFit: 'cover', borderRadius: 6 }} />
+      )}
+    </Space>
+  )
+
+  return (
+    <div>
+      <Row gutter={16}>
+        <Col xs={24} sm={8}>
+          <Card><Statistic title="借用记录总数" value={loans.length} prefix={<ClockCircleOutlined />} /></Card>
+        </Col>
+        <Col xs={24} sm={8}>
+          <Card><Statistic title="借用中" value={loaning} valueStyle={{ color: '#fa8c16' }} prefix={<SwapOutlined />} /></Card>
+        </Col>
+        <Col xs={24} sm={8}>
+          <Card><Statistic title="已归还" value={returned} valueStyle={{ color: '#52c41a' }} prefix={<CheckCircleOutlined />} /></Card>
+        </Col>
+      </Row>
+
+      <Card style={{ marginTop: 16 }}>
+        <Space wrap style={{ marginBottom: 16 }}>
+          <Select
+            value={statusFilter}
+            onChange={setStatusFilter}
+            style={{ width: 130 }}
+            options={[
+              { value: '', label: '全部状态' },
+              { value: '借用中', label: '借用中' },
+              { value: '已归还', label: '已归还' }
+            ]}
+          />
+          <Input.Search
+            placeholder="搜索设备 / 借用人"
+            allowClear
+            style={{ width: 220 }}
+            onSearch={setKeyword}
+          />
+          <Button type="primary" icon={<PlusOutlined />} onClick={openLoanModal}>借用设备</Button>
+        </Space>
+
+        <Table
+          rowKey="id"
+          columns={columns}
+          dataSource={filtered}
+          loading={loading}
+          locale={{ emptyText: <Empty description="暂无借用记录" /> }}
+          pagination={{ pageSize: 10, showSizeChanger: false }}
+          scroll={{ x: 900 }}
+        />
+      </Card>
+
+      {/* 借用弹窗 */}
+      <Modal
+        title="借用设备"
+        open={loanOpen}
+        onOk={submitLoan}
+        onCancel={() => setLoanOpen(false)}
+        okText="确认借用"
+        cancelText="取消"
+        confirmLoading={submitting}
+        width={520}
+      >
+        <Form form={loanForm} layout="vertical" style={{ marginTop: 12 }}>
+          <Form.Item name="device_id" label="借用设备" rules={[{ required: true, message: '请选择设备' }]}>
+            <Select showSearch optionFilterProp="label" placeholder="从已有设备中选择" options={deviceOptions} />
+          </Form.Item>
+          <Form.Item name="borrower" label="借用人" rules={[{ required: true, message: '请选择借用人' }]}>
+            <Select showSearch optionFilterProp="label" placeholder="从已有成员中选择" options={personnelOptions} />
+          </Form.Item>
+          <Form.Item label="借用照片">
+            {photoUploadBtn(loanPhotoPreview, handleLoanPhoto, loanPhoto ? '重新上传照片' : '上传借用照片')}
+          </Form.Item>
+          <Form.Item name="remark" label="备注">
+            <Input.TextArea rows={2} placeholder="选填，如借用用途等" />
+          </Form.Item>
+        </Form>
+        <p style={{ color: '#999', fontSize: 12 }}>确认借用后，服务器将自动记录借用时间。</p>
+      </Modal>
+
+      {/* 归还弹窗 */}
+      <Modal
+        title="归还设备"
+        open={returnOpen}
+        onOk={submitReturn}
+        onCancel={() => setReturnOpen(false)}
+        okText="确认归还"
+        cancelText="取消"
+        confirmLoading={submitting}
+        width={520}
+      >
+        <Form form={returnForm} layout="vertical" style={{ marginTop: 12 }}>
+          <Form.Item name="device_id" label="归还设备" rules={[{ required: true, message: '请选择设备' }]}>
+            <Select showSearch optionFilterProp="label" placeholder="从已有设备中选择" options={deviceOptions} />
+          </Form.Item>
+          <Form.Item name="borrower" label="归还人" rules={[{ required: true, message: '请选择归还人' }]}>
+            <Select showSearch optionFilterProp="label" placeholder="从已有成员中选择" options={personnelOptions} />
+          </Form.Item>
+          <Form.Item label="归还照片">
+            {photoUploadBtn(returnPhotoPreview, handleReturnPhoto, returnPhoto ? '重新上传照片' : '上传归还照片')}
+          </Form.Item>
+        </Form>
+        <p style={{ color: '#999', fontSize: 12 }}>确认归还后，服务器将自动记录归还时间。</p>
+      </Modal>
+    </div>
+  )
+}
+
+export default DeviceLoan
diff --git a/database.js b/database.js
index 6ddd6c2..5c6cd1d 100644
--- a/database.js
+++ b/database.js
@@ -125,6 +125,25 @@ function initDatabase() {
     )
   `);
 
+  // 设备借用记录表（借用/归还时间由服务器自动记录）
+  db.exec(`
+    CREATE TABLE IF NOT EXISTS device_loans (
+      id TEXT PRIMARY KEY,
+      device_id TEXT NOT NULL,
+      device_name TEXT DEFAULT '',
+      borrower_id TEXT DEFAULT '',
+      borrower TEXT DEFAULT '',
+      loan_photo TEXT DEFAULT '',
+      return_photo TEXT DEFAULT '',
+      status TEXT DEFAULT '借用中',
+      loan_time TEXT DEFAULT (datetime('now', 'localtime')),
+      return_time TEXT DEFAULT '',
+      remark TEXT DEFAULT '',
+      created_by TEXT DEFAULT '',
+      created_at TEXT DEFAULT (datetime('now', 'localtime'))
+    )
+  `);
+
   // 账户操作日志表
   db.exec(`
     CREATE TABLE IF NOT EXISTS user_logs (
diff --git a/package.json b/package.json
index 9b9e5b5..ba336bd 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "device-management-system",
-  "version": "2.2.0",
+  "version": "5.0.0",
   "description": "影视星河设备管理系统 - Device Management System",
   "main": "electron/main.js",
   "scripts": {
diff --git a/server.js b/server.js
index b86ed38..bac3609 100644
--- a/server.js
+++ b/server.js
@@ -48,6 +48,11 @@ function dropSession(token) {
   sessionActivity.delete(token);
 }
 
+// 下线时间列（兼容旧库：已存在则忽略）
+try {
+  db.prepare("ALTER TABLE users ADD COLUMN last_logout TEXT DEFAULT ''").run();
+} catch (e) { /* 列已存在 */ }
+
 // 收集当前在线用户（用户ID -> 最近活跃时间戳，取最新）
 function getOnlineUserMap() {
   const now = Date.now();
@@ -521,6 +526,85 @@ app.get('/api/personnel/stats/summary', (req, res) => {
   res.json({ success: true, data: { total, active, withAccount, departments } });
 });
 
+// ==================== 设备借用/归还 API ====================
+
+// 借用记录列表（可按状态/设备筛选，借用时间倒序）
+app.get('/api/loans', (req, res) => {
+  const { status, device_id } = req.query;
+  const conds = [];
+  const params = [];
+  if (status) { conds.push('status = ?'); params.push(status); }
+  if (device_id) { conds.push('device_id = ?'); params.push(device_id); }
+  const where = conds.length ? ' WHERE ' + conds.join(' AND ') : '';
+  const rows = db.prepare(`SELECT * FROM device_loans${where} ORDER BY loan_time DESC, rowid DESC LIMIT 200`).all(...params);
+  res.json({ success: true, data: rows });
+});
+
+// 创建借用（服务器自动记录借用时间）
+app.post('/api/loans', (req, res) => {
+  const { device_id, borrower, borrower_id, photo, remark } = req.body || {};
+  const device = db.prepare('SELECT * FROM devices WHERE id = ?').get(device_id || '');
+  if (!device) {
+    return res.status(400).json({ success: false, message: '请选择要借用的设备' });
+  }
+  if (!borrower || !String(borrower).trim()) {
+    return res.status(400).json({ success: false, message: '请选择借用人' });
+  }
+  const id = uuidv4();
+  db.prepare(`
+    INSERT INTO device_loans (id, device_id, device_name, borrower_id, borrower, loan_photo, remark, created_by)
+    VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+  `).run(id, device.id, device.name, borrower_id || '', String(borrower).trim(), photo || '', remark || '', getOperator(req));
+  const row = db.prepare('SELECT * FROM device_loans WHERE id = ?').get(id);
+  logDeviceAction(device.id, device.name, '借用', `${row.borrower} 借走设备`, getOperator(req));
+  pushToRole('admin', 'device_loan', '设备借用', `${row.borrower} 借用了设备「${device.name}」`, req.user.id);
+  res.json({ success: true, data: row, message: '借用成功' });
+});
+
+// 归还设备（服务器自动记录归还时间；设备/借用人可重新选择）
+app.post('/api/loans/:id/return', (req, res) => {
+  const loan = db.prepare('SELECT * FROM device_loans WHERE id = ?').get(req.params.id);
+  if (!loan) {
+    return res.status(404).json({ success: false, message: '借用记录不存在' });
+  }
+  if (loan.status === '已归还') {
+    return res.status(400).json({ success: false, message: '该设备已归还，请勿重复操作' });
+  }
+  const { device_id, borrower, borrower_id, photo } = req.body || {};
+  // 归还时可重新选择设备（从已有设备中选择）
+  let deviceId = loan.device_id;
+  let deviceName = loan.device_name;
+  if (device_id && device_id !== loan.device_id) {
+    const d = db.prepare('SELECT id, name FROM devices WHERE id = ?').get(device_id);
+    if (d) { deviceId = d.id; deviceName = d.name; }
+  }
+  const borrowerName = (borrower && String(borrower).trim()) || loan.borrower;
+  db.prepare(`
+    UPDATE device_loans
+    SET device_id = ?, device_name = ?, borrower = ?, borrower_id = ?,
+        return_photo = ?, status = '已归还', return_time = datetime('now', 'localtime')
+    WHERE id = ?
+  `).run(deviceId, deviceName, borrowerName, borrower_id || loan.borrower_id, photo || '', loan.id);
+  const row = db.prepare('SELECT * FROM device_loans WHERE id = ?').get(loan.id);
+  logDeviceAction(deviceId, deviceName, '归还', `${borrowerName} 归还设备`, getOperator(req));
+  pushToRole('admin', 'device_return', '设备归还', `${borrowerName} 已归还设备「${deviceName}」`, req.user.id);
+  res.json({ success: true, data: row, message: '归还成功' });
+});
+
+// 查看借用/归还照片（所有登录用户可见）
+app.get('/api/loans/photo/:fileId', (req, res) => {
+  const file = db.prepare('SELECT * FROM chat_files WHERE id = ?').get(req.params.fileId);
+  if (!file) {
+    return res.status(404).json({ success: false, message: '照片不存在' });
+  }
+  const filePath = path.join(uploadsDir, file.stored_name);
+  if (!fs.existsSync(filePath)) {
+    return res.status(404).json({ success: false, message: '照片文件已丢失' });
+  }
+  res.setHeader('Content-Type', file.file_mime || 'image/jpeg');
+  res.sendFile(filePath);
+});
+
 // ==================== 通知管理 API ====================
 
 // 获取所有通知
@@ -840,11 +924,15 @@ app.get('/api/chat/files/:id', (req, res) => {
   fs.createReadStream(filePath).pipe(res);
 });
 
-// 全部用户简表（选择聊天对象/建群成员，含在线状态）
+// 全部用户简表（选择聊天对象/建群成员，含在线状态与登录/下线时间）
 app.get('/api/chat/users', (req, res) => {
-  const rows = db.prepare('SELECT id, username, display_name, role FROM users ORDER BY created_at ASC').all();
+  const rows = db.prepare('SELECT id, username, display_name, role, last_login, last_logout FROM users ORDER BY created_at ASC').all();
   const onlineMap = getOnlineUserMap();
-  const data = rows.map(u => ({ ...u, is_online: onlineMap.has(u.id) }));
+  const data = rows.map(u => ({
+    ...u,
+    is_online: onlineMap.has(u.id),
+    last_active: onlineMap.has(u.id) ? formatActive(onlineMap.get(u.id)) : null
+  }));
   res.json({ success: true, data });
 });
 
@@ -1145,6 +1233,11 @@ app.get('/api/auth/me', (req, res) => {
 // 登出
 app.post('/api/auth/logout', (req, res) => {
   const token = req.headers.authorization?.replace('Bearer ', '');
+  const user = token ? sessions.get(token) : null;
+  if (user) {
+    // 记录下线时间
+    db.prepare("UPDATE users SET last_logout=datetime('now','localtime') WHERE id=?").run(user.id);
+  }
   if (token) dropSession(token);
   res.json({ success: true, message: '登出成功' });
 });
@@ -1167,6 +1260,47 @@ app.patch('/api/auth/password', (req, res) => {
   res.json({ success: true, message: '密码修改成功，请使用新密码重新登录' });
 });
 
+// ==================== App 版本检查与更新 ====================
+
+db.exec(`CREATE TABLE IF NOT EXISTS app_versions (
+  platform TEXT PRIMARY KEY,
+  version TEXT NOT NULL,
+  url TEXT DEFAULT '',
+  size INTEGER DEFAULT 0,
+  notes TEXT DEFAULT '',
+  released_at TEXT
+)`);
+
+// 首次启动播种当前四端 v4.0.0 版本信息（仅空表时写入）
+['windows', 'android', 'harmony', 'ios'].forEach(p => {
+  db.prepare("INSERT OR IGNORE INTO app_versions(platform, version, url, size, notes, released_at) VALUES(?, '4.0.0', '', 0, '影视星河设备管理系统 v4.0.0', datetime('now','localtime'))").run(p);
+});
+
+// 查询各端最新版本（客户端登录后检查更新用）
+app.get('/api/app/version/latest', (req, res) => {
+  const rows = db.prepare('SELECT * FROM app_versions').all();
+  const map = {};
+  rows.forEach(r => { map[r.platform] = r; });
+  res.json({ success: true, data: map });
+});
+
+// 管理员发布新版本：{ platform: windows|android|harmony|ios, version, url, size, notes }
+app.post('/api/app/version', requireAdmin, (req, res) => {
+  const { platform, version, url, size, notes } = req.body || {};
+  const platforms = ['windows', 'android', 'harmony', 'ios'];
+  if (!platforms.includes(platform)) {
+    return res.status(400).json({ success: false, message: '平台取值必须为 windows/android/harmony/ios' });
+  }
+  if (!version || !/^\d+\.\d+\.\d+$/.test(version)) {
+    return res.status(400).json({ success: false, message: '版本号格式必须为 x.y.z' });
+  }
+  db.prepare(`INSERT INTO app_versions(platform, version, url, size, notes, released_at)
+    VALUES(?,?,?,?,?,datetime('now','localtime'))
+    ON CONFLICT(platform) DO UPDATE SET version=excluded.version, url=excluded.url, size=excluded.size, notes=excluded.notes, released_at=excluded.released_at`)
+    .run(platform, version, url || '', size || 0, notes || '');
+  res.json({ success: true, message: platform + ' 端 v' + version + ' 已发布' });
+});
+
 // ==================== 天气 API ====================
 
 function getWeatherDesc(code) {