style: 知识库页面三处样式收尾：内容区扩展、隐藏入库时间列、上传区收小

frontend/src/pages/KnowledgeBase/KnowledgeBase.jsx

@@ -1,6 +1,6 @@
 import { useState, useEffect } from 'react'
 import { Card, Upload, Table, Button, Space, Select, Popconfirm, message, Tag } from 'antd'
-import { InboxOutlined, DeleteOutlined, ReloadOutlined } from '@ant-design/icons'
+import { InboxOutlined, DeleteOutlined, ReloadOutlined, UploadOutlined } from '@ant-design/icons'
 import useAuthStore from '../../stores/authStore'
 import knowledgeService from '../../services/knowledgeService'
 import KnowledgeTree from '../../components/KnowledgeTree/KnowledgeTree'
@@ -139,7 +139,7 @@ export default function KnowledgeBase() {
       title: '标题',
       dataIndex: 'title',
       key: 'title',
-      width: 240,
+      width: 280,
       render: (text) => (
         <span style={{ fontWeight: 500, color: '#3b4a3b', overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap', display: 'block' }}>{text}</span>
       ),
@@ -148,45 +148,38 @@ export default function KnowledgeBase() {
       title: '作者',
       dataIndex: 'author',
       key: 'author',
-      width: 80,
+      width: 100,
       render: (val) => val || '-',
     },
     {
       title: '播出/发表时间',
       dataIndex: 'publish_date',
       key: 'publish_date',
-      width: 156,
+      width: 160,
       render: (val) => val || '-',
     },
     {
       title: '出处',
       dataIndex: 'source_detail',
       key: 'source_detail',
-      width: 170,
+      width: 200,
       render: (val) => val || '-',
     },
     {
       title: '类型',
       dataIndex: 'source_type',
       key: 'source_type',
-      width: 88,
+      width: 96,
       render: (val) => (
         <Tag color="default" style={{ borderRadius: 8 }}>
           {SOURCE_TYPE_LABEL[val] || val}
         </Tag>
       ),
     },
-    {
-      title: '入库时间',
-      dataIndex: 'created_at',
-      key: 'created_at',
-      width: 140,
-      render: (val) => val ? new Date(val).toLocaleString('zh-CN', { hour12: false }).replace(' ', ' ') : '-',
-    },
     {
       title: '操作',
       key: 'action',
-      width: 86,
+      width: 90,
       render: (_, record) => (
         <Popconfirm
           title="确认删除"
@@ -205,33 +198,28 @@ export default function KnowledgeBase() {
   ]
 
   return (
-    <div style={{ maxWidth: 1200, padding: '12px' }}>
-      <div style={{ marginBottom: 12 }}>
-        <h2 style={{ margin: 0, fontSize: 18, fontWeight: 600, color: '#3b4a3b' }}>知识库</h2>
-        <p style={{ margin: '4px 0 0', fontSize: 12, color: '#888' }}>上传 md 笔记 · 语义检索 · 报题参考</p>
+    <div style={{ padding: '12px 16px' }}>
+      {/* 标题栏 */}
+      <div style={{ marginBottom: 10 }}>
+        <h2 style={{ margin: 0, fontSize: 20, fontWeight: 600, color: '#3b4a3b' }}>知识库</h2>
+        <p style={{ margin: '4px 0 0', fontSize: 13, color: '#888' }}>上传 md 笔记 · 语义检索 · 报题参考</p>
       </div>
 
-      {/* 上传区 */}
-      <Card style={{ borderRadius: 14, marginBottom: 12 }} bodyStyle={{ padding: 0 }}>
+      {/* 上传区（收小为一行） */}
+      <div style={{ display: 'flex', alignItems: 'center', gap: 10, marginBottom: 12 }}>
         <Dragger
           accept=".md"
           multiple
           showUploadList={false}
           beforeUpload={handleUpload}
           disabled={uploading}
-          style={{ padding: '28px 20px', borderRadius: 14 }}
         >
-          <p className="ant-upload-drag-icon" style={{ marginBottom: 8 }}>
-            <InboxOutlined style={{ fontSize: 40, color: '#6b8e6b' }} />
-          </p>
-          <p className="ant-upload-text" style={{ fontSize: 15, fontWeight: 500, color: '#3b4a3b' }}>
-            {uploading ? '正在上传并生成向量…' : '点击或拖拽 .md 文件上传'}
-          </p>
-          <p className="ant-upload-hint" style={{ fontSize: 12, color: '#888' }}>
-            支持批量上传，系统自动解析 yaml frontmatter 并生成语义向量
-          </p>
+          <Button icon={<UploadOutlined />} size="middle" style={{ borderRadius: 10 }}>
+            {uploading ? '正在上传并生成向量…' : '上传 md 文件入库'}
+          </Button>
         </Dragger>
-      </Card>
+        <span style={{ fontSize: 12, color: '#aaa' }}>支持批量上传，系统自动解析 yaml frontmatter 并生成语义向量</span>
+      </div>
 
       {/* 主体：左侧树 + 右侧列表 */}
       <div style={{ display: 'flex', gap: 12, alignItems: 'flex-start' }}>
@@ -252,7 +240,7 @@ export default function KnowledgeBase() {
           {/* 筛选栏 */}
           <Card style={{ borderRadius: 14, marginBottom: 12 }}>
             <Space size="middle" wrap>
-              <span style={{ fontSize: 13, color: '#666' }}>筛选：</span>
+              <span style={{ fontSize: 14, color: '#666' }}>筛选：</span>
               <Select
                 placeholder="按类型"
                 options={SOURCE_TYPE_OPTIONS}