UI彻底重做: 全新设计语言, 纯手工精调

设计系统:
- CSS变量体系: 暖纸底色(#F9F7F4), 6级灰阶, 5级阴影
- 字体节奏: clamp响应式字号, -0.02em字间距
- 间距韵律: 4-128px 8级递进

首页:
- 96px大留白英雄区, clamp(36px,5vw,56px)巨型标题
- 200px暗色封面卡片(#2C2824)
- LIVE红点脉动标签, 待开播黑底白字徽章
- hover抬升2px + 阴影, 淡棕描边高亮

管理页:
- stat卡片: 1px边框+3px彩色顶线
- 表格卡片化: borderRadius 12, 统一白底+边框
- 表单/设置: 统一圆角8px, 大内边距36px

播放页:
- #1A1814暗底, 毛玻璃顶栏
- 视频圆角12px + boxShadow景深
- document.title动态标题

登录页: 56px内边距, 品牌居中, 返回链接

frontend/src/admin/pages/Dashboard.tsx

@@ -1,5 +1,5 @@
 import { useState, useEffect } from 'react'
-import { Row, Col, Card, Statistic, Typography, Table, Tag, Skeleton } from 'antd'
+import { Row, Col, Statistic, Table, Tag, Typography } from 'antd'
 import { SignalFilled, ClockCircleOutlined, PlayCircleOutlined } from '@ant-design/icons'
 import { fetchStreams, type StreamInfo } from '../../api/streams'
 import { useBrand } from '../../brand/BrandContext'
@@ -11,11 +11,7 @@ export default function Dashboard() {
   const [streams, setStreams] = useState<StreamInfo[]>([])
   const [loading, setLoading] = useState(true)
 
-  useEffect(() => {
-    loadData()
-    const timer = setInterval(loadData, 10000)
-    return () => clearInterval(timer)
-  }, [])
+  useEffect(() => { loadData(); const t = setInterval(loadData, 10000); return () => clearInterval(t) }, [])
 
   async function loadData() {
     try { setStreams(await fetchStreams()) } catch { /* */ }
@@ -34,47 +30,63 @@ export default function Dashboard() {
 
   const columns = [
     { title: '标题', dataIndex: 'title', key: 'title', ellipsis: true },
-    { title: '状态', dataIndex: 'status', key: 'status', width: 100,
+    { title: '状态', dataIndex: 'status', key: 'status', width: 90,
       render: (s: string) => <Tag color={(statusMap[s] || {}).color}>{(statusMap[s] || { label: s }).label}</Tag> },
     { title: '创建时间', dataIndex: 'created_at', key: 'created_at', render: (v: string) => v?.slice(0, 16), width: 170 },
   ]
 
   return (
     <div>
-      <div style={{ marginBottom: 32 }}>
-        <Title level={2} style={{ margin: 0, fontWeight: 600 }}>{brand.brand_name}</Title>
-        <Text type="secondary" style={{ fontSize: 15 }}>管理控制台</Text>
+      <div style={{ marginBottom: 36 }}>
+        <Title level={1} style={{ margin: '0 0 8px', fontWeight: 600, fontSize: 32, letterSpacing: '-0.03em' }}>
+          {brand.brand_name}
+        </Title>
+        <Text style={{ color: '#5E5A52', fontSize: 15 }}>管理控制台</Text>
       </div>
 
-      <Row gutter={[28, 28]} style={{ marginBottom: 32 }}>
+      <Row gutter={[24, 24]} style={{ marginBottom: 36 }}>
         <Col xs={24} sm={8}>
-          <Card style={{ borderRadius: 12, borderTop: '3px solid #5B8C5A' }}>
+          <div style={{
+            background: '#fff', borderRadius: 12, padding: '28px 32px',
+            border: '1px solid #EBE5DB',
+            borderTop: '3px solid #5B8C5A',
+          }}>
             <Statistic title="直播中" value={liveCount} loading={loading}
-              prefix={<SignalFilled style={{ color: '#5B8C5A', fontSize: 18 }} />} />
-          </Card>
+              prefix={<SignalFilled style={{ color: '#5B8C5A', fontSize: 20 }} />} />
+          </div>
         </Col>
         <Col xs={24} sm={8}>
-          <Card style={{ borderRadius: 12, borderTop: '3px solid #6B8CA8' }}>
+          <div style={{
+            background: '#fff', borderRadius: 12, padding: '28px 32px',
+            border: '1px solid #EBE5DB',
+            borderTop: '3px solid #6B8CA8',
+          }}>
             <Statistic title="待开播" value={pendingCount} loading={loading}
-              prefix={<ClockCircleOutlined style={{ color: '#6B8CA8', fontSize: 18 }} />} />
-          </Card>
+              prefix={<ClockCircleOutlined style={{ color: '#6B8CA8', fontSize: 20 }} />} />
+          </div>
         </Col>
         <Col xs={24} sm={8}>
-          <Card style={{ borderRadius: 12, borderTop: '3px solid #C2693A' }}>
+          <div style={{
+            background: '#fff', borderRadius: 12, padding: '28px 32px',
+            border: '1px solid #EBE5DB',
+            borderTop: '3px solid #C2693A',
+          }}>
             <Statistic title="直播总数" value={streams.length} loading={loading}
-              prefix={<PlayCircleOutlined style={{ color: '#C2693A', fontSize: 18 }} />} />
-          </Card>
+              prefix={<PlayCircleOutlined style={{ color: '#C2693A', fontSize: 20 }} />} />
+          </div>
         </Col>
       </Row>
 
-      <Card
-        title={<Title level={4} style={{ margin: 0, fontWeight: 600 }}>最近直播</Title>}
-        style={{ borderRadius: 12 }}
-      >
+      <div style={{
+        background: '#fff', borderRadius: 12,
+        border: '1px solid #EBE5DB',
+        padding: '28px 32px',
+      }}>
+        <Title level={4} style={{ margin: '0 0 20px', fontWeight: 600 }}>最近直播</Title>
         <Table dataSource={streams.slice(0, 10)} columns={columns}
           rowKey="id" loading={loading} pagination={false} size="middle"
           locale={{ emptyText: '暂无直播数据' }} />
-      </Card>
+      </div>
     </div>
   )
 }