diff --git a/frontend/package.json b/frontend/package.json
index ba8fa5a..c0ef179 100644
--- a/frontend/package.json
+++ b/frontend/package.json
@@ -11,6 +11,7 @@
     "test:data-process-list": "node scripts/regression-data-process-list.mjs",
     "test:data-process-wizard": "node scripts/regression-data-process-wizard.mjs",
     "test:dataset-task-tab": "node scripts/regression-dataset-task-tab.mjs",
+    "test:dataset-preview": "node scripts/regression-dataset-preview.mjs",
     "test:model-manage": "node scripts/regression-model-manage.mjs",
     "test:training-log-layout": "node scripts/regression-training-log-layout.mjs",
     "test:page-surface": "node scripts/regression-page-surface.mjs"
diff --git a/frontend/scripts/regression-dataset-preview.mjs b/frontend/scripts/regression-dataset-preview.mjs
new file mode 100644
index 0000000..dec2bd8
--- /dev/null
+++ b/frontend/scripts/regression-dataset-preview.mjs
@@ -0,0 +1,29 @@
+import fs from 'node:fs'
+import path from 'node:path'
+
+const root = process.cwd()
+const previewPath = path.join(root, 'src/views/dataset/DatasetPreviewView.vue')
+const mockPath = path.join(root, 'src/mock/data.ts')
+const source = fs.readFileSync(previewPath, 'utf8')
+const mockSource = fs.readFileSync(mockPath, 'utf8')
+
+function expect(condition, message) {
+  if (!condition) throw new Error(message)
+}
+
+expect(source.includes('class="preview-workspace"'), '预览页应使用文件与内容双栏工作区')
+expect(source.includes('class="code-line"'), '内容查看器应提供逐行展示')
+expect(source.includes('class="line-number"'), '内容查看器应显示行号')
+expect(source.includes('previewLoading'), '切换文件时应提供独立加载状态')
+expect(source.includes('previewError'), '内容加载失败时应提供错误状态')
+expect(source.includes('aria-current'), '文件选中态应向辅助技术暴露')
+expect(!source.includes('handleDownloadAll'), '页面不应保留整包下载逻辑')
+expect(!source.includes('handleDelete'), '页面不应保留删除逻辑')
+expect(!source.includes('router.back()'), '页面不应保留页头返回逻辑')
+expect(mockSource.includes('files: ['), 'Mock 数据集应包含可验收的文件列表')
+expect(mockSource.includes('mockDatasetPreviews'), 'Mock 数据应包含文件预览内容')
+expect(mockSource.includes("'mock-jsonl'"), 'Mock 数据应为通用数据集提供模拟样本')
+expect(mockSource.includes("'mock-readme'"), 'Mock 数据应为通用数据集提供模拟说明')
+expect(mockSource.includes('.map((dataset)'), '所有 Mock 数据集都应自动补齐预览文件')
+
+console.log('dataset preview regression checks passed')
diff --git a/frontend/src/mock/adapter.ts b/frontend/src/mock/adapter.ts
index 1f185f7..7460a72 100644
--- a/frontend/src/mock/adapter.ts
+++ b/frontend/src/mock/adapter.ts
@@ -12,6 +12,7 @@ import {
   mockTrainedModels,
   mockLocalModels,
   mockDatasets,
+  mockDatasetPreviews,
   mockFineTuneList,
   mockCompareList,
   mockEvalList,
@@ -129,7 +130,12 @@ async function handleMock(config: AxiosRequestConfig) {
   m = url.match(/^\/dataset-manage\/upload\/([^/]+)$/)
   if (m && method === 'post') return ok({ uploaded: true })
   m = url.match(/^\/dataset-manage\/preview\/([^/]+)$/)
-  if (m && method === 'get') return ok(mockLogContent)
+  if (m && method === 'get') {
+    const fileId = decodeURIComponent(m[1])
+    const fallbackKey = fileId.endsWith('-readme') ? 'mock-readme' : 'mock-jsonl'
+    const content = mockDatasetPreviews[fileId] ?? mockDatasetPreviews[fallbackKey]
+    return ok({ content })
+  }
 
   // ==================== 训练任务 ====================
   if (url === '/fine-tune' && method === 'get') return ok(mockFineTuneList)
@@ -265,4 +271,4 @@ export function installMockAdapter(instance: AxiosInstance) {
       return fail(e.message || 'Mock 错误', 500, config)
     }
   }
-}
\ No newline at end of file
+}
diff --git a/frontend/src/mock/data.ts b/frontend/src/mock/data.ts
index 0e2dc05..8a3a326 100644
--- a/frontend/src/mock/data.ts
+++ b/frontend/src/mock/data.ts
@@ -99,7 +99,22 @@ export const mockLocalModels = {
 
 // ============ 数据集 ============
 export const mockDatasets: DatasetItem[] = [
-  { id: 1, name: '金融问答-训练集', type: 'train', storage_type: 'local', source: 'upload', size: '128 MB', count: 8560, description: '金融领域问答对', create_time: '2025-12-20T08:00:00Z' },
+  {
+    id: 1,
+    name: '金融问答-训练集',
+    type: 'train',
+    storage_type: 'local',
+    source: 'upload',
+    size: '128 MB',
+    count: 8560,
+    description: '面向金融领域问答场景的高质量指令微调数据集',
+    create_time: '2025-12-20T08:00:00Z',
+    files: [
+      { id: 'finance-train-jsonl', name: 'finance_train.jsonl', size: '86.4 MB' },
+      { id: 'finance-validation-jsonl', name: 'finance_validation.jsonl', size: '21.8 MB' },
+      { id: 'dataset-readme', name: 'README.md', size: '4.2 KB' },
+    ],
+  },
   { id: 2, name: '法律文书-训练集', type: 'train', storage_type: 'local', source: 'upload', size: '256 MB', count: 15230, description: '法律文书数据集', create_time: '2025-12-25T10:30:00Z' },
   { id: 3, name: '客服对话-训练集', type: 'train', storage_type: 'minio', source: 'upload', size: '512 MB', count: 24500, description: '客服对话记录', create_time: '2026-01-05T14:20:00Z' },
   { id: 4, name: '金融评测集', type: 'eval', storage_type: 'local', source: 'upload', size: '32 MB', count: 1200, description: '金融领域评测', create_time: '2026-01-10T09:15:00Z' },
@@ -109,16 +124,81 @@ export const mockDatasets: DatasetItem[] = [
   { id: 8, name: '通用指令构造集', type: 'train', storage_type: 'local', source: 'task', size: '148 MB', count: 12600, description: '由指令微调数据构造任务生成', create_time: '2026-07-09T01:42:00Z' },
   { id: 9, name: '用户反馈脱敏集', type: 'test', storage_type: 'minio', source: 'task', size: '72 MB', count: 9340, description: '由敏感信息脱敏任务生成', create_time: '2026-07-09T09:18:00Z' },
   { id: 10, name: '多轮对话增强集', type: 'eval', storage_type: 'local', source: 'task', size: '41 MB', count: 2780, description: '由多轮对话拼接任务生成', create_time: '2026-07-10T02:06:00Z' },
-]
+].map((dataset) => ({
+  ...dataset,
+  files: dataset.files?.length
+    ? dataset.files
+    : [
+        { id: `dataset-${dataset.id}-samples`, name: 'dataset_samples.jsonl', size: dataset.size || '12.8 MB' },
+        { id: `dataset-${dataset.id}-readme`, name: 'README.md', size: '3.8 KB' },
+      ],
+}))
+
+export const mockDatasetPreviews: Record<string, string> = {
+  'finance-train-jsonl': [
+    '{"instruction":"什么是净资产收益率？","input":"","output":"净资产收益率（ROE）用于衡量企业运用自有资本获得收益的能力。"}',
+    '{"instruction":"解释市盈率的含义","input":"某公司股价为 36 元，每股收益为 3 元。","output":"市盈率为股价除以每股收益，本例中市盈率为 12 倍。"}',
+    '{"instruction":"央行降准通常会带来什么影响？","input":"","output":"降准通常会释放银行体系流动性，降低资金成本，并增强信贷投放能力。"}',
+    '{"instruction":"如何理解债券久期？","input":"","output":"久期衡量债券价格对利率变化的敏感程度，久期越长，价格波动通常越大。"}',
+    '{"instruction":"基金定投适合怎样的投资者？","input":"","output":"基金定投适合希望分散择时风险、进行中长期纪律性投资的投资者。"}',
+    '{"instruction":"资产负债率过高意味着什么？","input":"","output":"可能意味着企业偿债压力较大、财务风险较高，但仍需结合行业特点判断。"}',
+    '{"instruction":"通货膨胀如何影响实际收益率？","input":"","output":"实际收益率约等于名义收益率减去通货膨胀率。"}',
+    '{"instruction":"什么是流动比率？","input":"","output":"流动比率等于流动资产除以流动负债，用于衡量短期偿债能力。"}',
+    '{"instruction":"股票分红是否等于投资者获得额外收益？","input":"","output":"不完全等同，除息后股价通常会相应调整，应结合总回报判断。"}',
+    '{"instruction":"如何区分系统性风险与非系统性风险？","input":"","output":"系统性风险影响整个市场，非系统性风险主要与单个公司或行业有关。"}',
+    '{"instruction":"什么是复利？","input":"","output":"复利是将本金和此前产生的收益一并计入下一期收益计算。"}',
+    '{"instruction":"现金流量表主要反映什么？","input":"","output":"现金流量表反映企业经营、投资和筹资活动产生的现金流入与流出。"}',
+  ].join('\n'),
+  'finance-validation-jsonl': [
+    '{"instruction":"计算简单收益率","input":"买入价 100 元，卖出价 108 元，不考虑费用。","output":"简单收益率为 8%。"}',
+    '{"instruction":"什么是信用利差？","input":"","output":"信用利差是信用债收益率相对无风险基准收益率的差额。"}',
+    '{"instruction":"解释最大回撤","input":"","output":"最大回撤描述资产净值从历史高点到随后低点的最大跌幅。"}',
+    '{"instruction":"什么是风险溢价？","input":"","output":"风险溢价是投资者因承担额外风险而要求的超额预期收益。"}',
+  ].join('\n'),
+  'dataset-readme': [
+    '# 金融问答训练集',
+    '',
+    '本数据集用于金融领域指令微调与基础能力评测。',
+    '',
+    '## 文件说明',
+    '',
+    '- `finance_train.jsonl`：训练样本',
+    '- `finance_validation.jsonl`：验证样本',
+    '',
+    '文本编码：UTF-8',
+  ].join('\n'),
+  'mock-jsonl': [
+    '{"instruction":"请概括以下文本的核心观点","input":"人工智能正在提升企业的数据处理效率。","output":"人工智能能够帮助企业提升数据处理效率。"}',
+    '{"instruction":"将用户问题改写为更清晰的表达","input":"这个功能咋用？","output":"请说明该功能的具体使用步骤。"}',
+    '{"instruction":"判断文本情感倾向","input":"这次服务响应很及时，问题也解决了。","output":"正向"}',
+    '{"instruction":"提取文本中的关键实体","input":"远光软件于周一发布了新的模型管理平台。","output":["远光软件","周一","模型管理平台"]}',
+    '{"instruction":"生成简短回复","input":"您好，我想了解数据集上传支持哪些格式？","output":"您好，目前支持 JSON、JSONL、CSV、TXT 等常见格式。"}',
+    '{"instruction":"对以下内容进行分类","input":"如何重置账户密码？","output":"账户与安全"}',
+    '{"instruction":"找出句子中的时间信息","input":"系统将在 7 月 15 日凌晨 2 点进行升级。","output":"7 月 15 日凌晨 2 点"}',
+    '{"instruction":"补全客服回复","input":"用户反馈页面加载缓慢。","output":"已收到您的反馈，我们正在排查页面加载问题，请稍后重试。"}',
+  ].join('\n'),
+  'mock-readme': [
+    '# 数据集说明',
+    '',
+    '当前内容为前端 Mock 数据，用于预览页面布局与交互效果。',
+    '',
+    '## 文件结构',
+    '',
+    '- `dataset_samples.jsonl`：模拟的数据样本',
+    '- `README.md`：数据集使用说明',
+    '',
+    '文本编码：UTF-8',
+  ].join('\n'),
+}
 
 // ============ 训练任务 ============
 export const mockFineTuneList: FineTuneTask[] = [
-  { id: 1, name: 'finance-sft-001', description: '金融领域 SFT 训练', status: 'completed', train_type: 'SFT', train_method: 'lora', template: 'qwen', base_model: 1, train_dataset_id: 1, gpus: [0], progress: 100, train_duration: '2小时18分钟', create_time: '2026-01-15T08:00:00Z' },
-  { id: 2, name: 'legal-sft-002', description: '法律文书 SFT', status: 'completed', train_type: 'SFT', train_method: 'lora', template: 'qwen', base_model: 1, train_dataset_id: 2, gpus: [1], progress: 100, train_duration: '1小时46分钟', create_time: '2026-01-18T10:00:00Z' },
-  { id: 3, name: 'medical-cpt-001', description: '医疗领域继续预训练', status: 'running', train_type: 'CPT', train_method: 'lora', template: 'qwen2_5', base_model: 2, train_dataset_id: 6, gpus: [0, 1], progress: 64, train_duration: '36分钟', create_time: '2026-02-05T09:00:00Z' },
-  { id: 4, name: 'service-dpo-001', description: '客服对话偏好训练', status: 'pending', train_type: 'DPO', train_method: 'lora', template: 'qwen', base_model: 1, train_dataset_id: 3, gpus: [2], progress: 0, train_duration: '-', create_time: '2026-02-08T14:00:00Z' },
-  { id: 5, name: 'finance-sft-002', description: '金融领域二轮微调', status: 'failed', train_type: 'SFT', train_method: 'lora', template: 'qwen', base_model: 1, train_dataset_id: 1, gpus: [3], progress: 32, train_duration: '18分钟', create_time: '2026-02-10T11:00:00Z' },
-  { id: 6, name: 'general-sft-001', description: '通用能力微调', status: 'completed', train_type: 'SFT', train_method: 'full', template: 'llama3', base_model: 3, train_dataset_id: 3, gpus: [0, 2], progress: 100, train_duration: '3小时05分钟', create_time: '2026-02-12T13:00:00Z' },
+  { id: 103942, name: 'finance-sft-001', description: '金融领域 SFT 训练', status: 'completed', train_type: 'SFT', train_method: 'lora', template: 'qwen', base_model: 1, train_dataset_id: 1, gpus: [0], progress: 100, train_duration: '2小时18分钟', create_time: '2026-01-15T08:00:00Z' },
+  { id: 349102, name: 'legal-sft-002', description: '法律文书 SFT', status: 'completed', train_type: 'SFT', train_method: 'lora', template: 'qwen', base_model: 1, train_dataset_id: 2, gpus: [1], progress: 100, train_duration: '1小时46分钟', create_time: '2026-01-18T10:00:00Z' },
+  { id: 849301, name: 'medical-cpt-001', description: '医疗领域继续预训练', status: 'running', train_type: 'CPT', train_method: 'lora', template: 'qwen2_5', base_model: 2, train_dataset_id: 6, gpus: [0, 1], progress: 64, train_duration: '36分钟', create_time: '2026-02-05T09:00:00Z' },
+  { id: 593021, name: 'service-dpo-001', description: '客服对话偏好训练', status: 'pending', train_type: 'DPO', train_method: 'lora', template: 'qwen', base_model: 1, train_dataset_id: 3, gpus: [2], progress: 0, train_duration: '-', create_time: '2026-02-08T14:00:00Z' },
+  { id: 201948, name: 'finance-sft-002', description: '金融领域二轮微调', status: 'failed', train_type: 'SFT', train_method: 'lora', template: 'qwen', base_model: 1, train_dataset_id: 1, gpus: [3], progress: 32, train_duration: '18分钟', create_time: '2026-02-10T11:00:00Z' },
+  { id: 940212, name: 'general-sft-001', description: '通用能力微调', status: 'completed', train_type: 'SFT', train_method: 'full', template: 'llama3', base_model: 3, train_dataset_id: 3, gpus: [0, 2], progress: 100, train_duration: '3小时05分钟', create_time: '2026-02-12T13:00:00Z' },
 ]
 
 // ============ 模型推理/对比 ============
diff --git a/frontend/src/views/dataset/DatasetPreviewView.vue b/frontend/src/views/dataset/DatasetPreviewView.vue
index a96f6b2..c072d23 100644
--- a/frontend/src/views/dataset/DatasetPreviewView.vue
+++ b/frontend/src/views/dataset/DatasetPreviewView.vue
@@ -1,157 +1,697 @@
 <script setup lang="ts">
-import { ref, computed, onMounted } from 'vue'
-import { useRoute, useRouter } from 'vue-router'
-import { ElMessage, ElMessageBox } from 'element-plus'
+import { computed, onMounted, ref } from 'vue'
+import { useRoute } from 'vue-router'
 import PageCard from '@/components/PageCard.vue'
-import {
-  getDataset,
-  previewDatasetFile,
-  deleteDataset,
-  downloadDatasetUrl,
-  downloadFileUrl,
-} from '@/api/modules/dataset'
+import { downloadFileUrl, getDataset, previewDatasetFile } from '@/api/modules/dataset'
 import { DATASET_TYPE_MAP, STORAGE_MAP } from '@/constants'
-import type { DatasetItem, DatasetFile } from '@/types'
+import type { DatasetFile, DatasetItem } from '@/types'
 
 const route = useRoute()
-const router = useRouter()
 const datasetId = route.params.id as string
 
 const loading = ref(false)
+const previewLoading = ref(false)
 const dataset = ref<DatasetItem | null>(null)
-const selectedFileId = ref<string>('')
+const selectedFileId = ref('')
 const previewContent = ref('')
+const previewError = ref('')
+let previewRequestId = 0
 
 const files = computed<DatasetFile[]>(() => dataset.value?.files || [])
+const selectedFile = computed(() => files.value.find((file) => fileKey(file) === selectedFileId.value))
+const previewLines = computed(() => previewContent.value ? previewContent.value.split('\n').slice(0, 100) : [])
+const totalLines = computed(() => previewContent.value ? previewContent.value.split('\n').length : 0)
+const datasetType = computed(() => {
+  const value = String(dataset.value?.type || '').toLowerCase()
+  return DATASET_TYPE_MAP[value] || dataset.value?.type || '-'
+})
+const storageType = computed(() => {
+  const value = dataset.value?.storage_type || ''
+  return STORAGE_MAP[value] || value || '-'
+})
+const createdAt = computed(() => dataset.value?.create_time
+  ? new Date(dataset.value.create_time).toLocaleString('zh-CN')
+  : '-')
 
-const previewLines = computed(() => previewContent.value.split('\n').slice(0, 100))
-const totalLines = computed(() => previewContent.value.split('\n').length)
+function fileKey(file: DatasetFile) {
+  return String(file.id || file.name)
+}
+
+function fileExtension(fileName = '') {
+  return fileName.includes('.') ? fileName.split('.').pop()?.toUpperCase() : 'FILE'
+}
 
 async function loadDataset() {
   loading.value = true
   try {
     dataset.value = await getDataset(datasetId)
-    if (files.value.length > 0) {
-      selectedFileId.value = String(files.value[0].id || files.value[0].name)
-      loadPreview()
-    }
-  } catch {
-    // ignore
+    const firstFile = files.value[0]
+    if (firstFile) await selectFile(firstFile)
   } finally {
     loading.value = false
   }
 }
 
-async function loadPreview() {
-  if (!selectedFileId.value) return
+async function selectFile(file: DatasetFile) {
+  const nextFileId = fileKey(file)
+  selectedFileId.value = nextFileId
+  previewContent.value = ''
+  previewError.value = ''
+  previewLoading.value = true
+  const requestId = ++previewRequestId
+
   try {
-    const res = await previewDatasetFile(selectedFileId.value)
-    previewContent.value = res.content || ''
+    const res = await previewDatasetFile(nextFileId)
+    if (requestId === previewRequestId) previewContent.value = res.content || ''
   } catch {
-    previewContent.value = '加载失败'
+    if (requestId === previewRequestId) previewError.value = '内容加载失败，请稍后重试'
+  } finally {
+    if (requestId === previewRequestId) previewLoading.value = false
   }
 }
 
-function handleDownloadFile(file: any) {
-  const fid = file.id || file.name
-  window.open(downloadFileUrl(datasetId, fid), '_blank')
-}
-
-function handleDownloadAll() {
-  window.open(downloadDatasetUrl(datasetId), '_blank')
-}
-
-async function handleDelete() {
-  await ElMessageBox.confirm('确定要删除这个数据集吗？', '确认删除', { type: 'warning' })
-  await deleteDataset(datasetId)
-  ElMessage.success('删除成功')
-  router.push('/dataset')
+function handleDownloadFile(file: DatasetFile) {
+  window.open(downloadFileUrl(datasetId, fileKey(file)), '_blank')
 }
 
 onMounted(loadDataset)
 </script>
 
 <template>
-  <PageCard title="数据集预览" v-loading="loading">
-    <template #extra>
-      <el-button @click="handleDownloadAll"><i class="fa fa-download" /> 打包下载</el-button>
-      <el-button type="danger" @click="handleDelete"><i class="fa fa-trash" /> 删除</el-button>
-      <el-button @click="router.back()">返回</el-button>
+  <PageCard class="dataset-preview-page" v-loading="loading">
+    <template #header>
+      <div class="page-heading">
+        <div class="heading-icon" aria-hidden="true">
+          <i class="fa fa-database" />
+        </div>
+        <div>
+          <div class="heading-row">
+            <h1>{{ dataset?.name || '数据集预览' }}</h1>
+            <el-tag size="small" type="primary">{{ datasetType }}</el-tag>
+            <el-tag size="small" type="success">{{ storageType }}</el-tag>
+          </div>
+          <p>{{ dataset?.description || '查看数据集文件及内容样本' }}</p>
+        </div>
+      </div>
     </template>
 
-    <!-- 数据集信息 -->
-    <el-descriptions :column="3" border style="margin-bottom: 20px">
-      <el-descriptions-item label="名称">{{ dataset?.name }}</el-descriptions-item>
-      <el-descriptions-item label="类型">
-        {{ DATASET_TYPE_MAP[String(dataset?.type).toLowerCase()] || dataset?.type }}
-      </el-descriptions-item>
-      <el-descriptions-item label="存储位置">
-        {{ STORAGE_MAP[dataset?.storage_type || ''] || dataset?.storage_type }}
-      </el-descriptions-item>
-      <el-descriptions-item label="数据条数">{{ dataset?.count || 0 }}</el-descriptions-item>
-      <el-descriptions-item label="创建时间">
-        {{ dataset?.create_time ? new Date(dataset.create_time).toLocaleString('zh-CN') : '-' }}
-      </el-descriptions-item>
-      <el-descriptions-item label="描述">{{ dataset?.description || '-' }}</el-descriptions-item>
-    </el-descriptions>
-
-    <!-- 文件列表 -->
-    <div class="file-section">
-      <h3 class="section-title">文件列表</h3>
-      <el-table :data="files" style="width: 100%">
-        <el-table-column label="文件名" prop="name" />
-        <el-table-column label="大小" prop="size" width="120" />
-        <el-table-column label="操作" width="200" align="center">
-          <template #default="{ row }">
-            <el-button link type="primary" @click="selectedFileId = String(row.id || row.name); loadPreview()">预览</el-button>
-            <el-button link type="success" @click="handleDownloadFile(row)">下载</el-button>
-          </template>
-        </el-table-column>
-      </el-table>
-    </div>
-
-    <!-- 预览内容 -->
-    <div class="preview-section">
-      <h3 class="section-title">内容预览</h3>
-      <pre class="preview-pre">{{ previewLines.join('\n') }}</pre>
-      <div v-if="totalLines > 100" class="preview-footer">
-        ... 共 {{ totalLines }} 条记录，已显示前 100 条 ...
+    <section class="dataset-overview" aria-label="数据集概览">
+      <div class="overview-item">
+        <span>数据条数</span>
+        <strong>{{ (dataset?.count || 0).toLocaleString() }}</strong>
       </div>
-    </div>
+      <div class="overview-item">
+        <span>数据大小</span>
+        <strong>{{ dataset?.size || '-' }}</strong>
+      </div>
+      <div class="overview-item">
+        <span>文件数量</span>
+        <strong>{{ files.length }}</strong>
+      </div>
+      <div class="overview-item overview-item-wide">
+        <span>创建时间</span>
+        <strong>{{ createdAt }}</strong>
+      </div>
+    </section>
+
+    <section v-if="files.length" class="preview-workspace" aria-label="数据集文件预览">
+      <aside class="file-pane">
+        <div class="pane-heading">
+          <div>
+            <span class="pane-eyebrow">FILES</span>
+            <h2>数据文件</h2>
+          </div>
+          <span class="file-count">{{ files.length }}</span>
+        </div>
+
+        <nav class="file-list" aria-label="数据文件列表">
+          <button
+            v-for="file in files"
+            :key="fileKey(file)"
+            type="button"
+            class="file-item"
+            :class="{ 'is-active': fileKey(file) === selectedFileId }"
+            :aria-current="fileKey(file) === selectedFileId ? 'true' : undefined"
+            @click="selectFile(file)"
+          >
+            <span class="file-type" aria-hidden="true">{{ fileExtension(file.name) }}</span>
+            <span class="file-copy">
+              <strong :title="file.name">{{ file.name }}</strong>
+              <small>{{ file.size || '未知大小' }}</small>
+            </span>
+            <i v-if="fileKey(file) === selectedFileId" class="fa fa-angle-right" aria-hidden="true" />
+          </button>
+        </nav>
+      </aside>
+
+      <div class="content-pane">
+        <div class="content-toolbar">
+          <div class="content-title">
+            <span class="file-icon" aria-hidden="true"><i class="fa fa-file-text-o" /></span>
+            <div>
+              <h2>{{ selectedFile?.name }}</h2>
+              <p>
+                {{ selectedFile?.size || '未知大小' }}
+                <span aria-hidden="true">·</span>
+                {{ totalLines.toLocaleString() }} 行
+                <span v-if="totalLines > 100" aria-hidden="true">·</span>
+                <span v-if="totalLines > 100">显示前 100 行</span>
+              </p>
+            </div>
+          </div>
+          <el-tooltip content="下载当前文件" placement="top">
+            <el-button
+              class="download-button"
+              aria-label="下载当前文件"
+              :disabled="!selectedFile"
+              @click="selectedFile && handleDownloadFile(selectedFile)"
+            >
+              <i class="fa fa-download" />
+              下载文件
+            </el-button>
+          </el-tooltip>
+        </div>
+
+        <div class="viewer-shell" :aria-busy="previewLoading">
+          <div v-if="previewLoading" class="viewer-state">
+            <i class="fa fa-circle-o-notch fa-spin" aria-hidden="true" />
+            <span>正在加载文件内容…</span>
+          </div>
+
+          <div v-else-if="previewError" class="viewer-state viewer-state-error" role="alert">
+            <i class="fa fa-exclamation-circle" aria-hidden="true" />
+            <strong>{{ previewError }}</strong>
+            <el-button size="small" @click="selectedFile && selectFile(selectedFile)">重新加载</el-button>
+          </div>
+
+          <div v-else-if="!previewLines.length" class="viewer-state">
+            <i class="fa fa-file-o" aria-hidden="true" />
+            <span>当前文件暂无可预览内容</span>
+          </div>
+
+          <div v-else class="code-viewer" tabindex="0" :aria-label="`${selectedFile?.name || ''} 文件内容`">
+            <div v-for="(line, index) in previewLines" :key="index" class="code-line">
+              <span class="line-number" aria-hidden="true">{{ index + 1 }}</span>
+              <code>{{ line || ' ' }}</code>
+            </div>
+          </div>
+        </div>
+
+        <div class="viewer-footer">
+          <span><i class="fa fa-eye" aria-hidden="true" /> 只读预览</span>
+          <span>UTF-8</span>
+        </div>
+      </div>
+    </section>
+
+    <section v-else-if="!loading" class="empty-files" aria-label="空文件列表">
+      <span class="empty-icon" aria-hidden="true"><i class="fa fa-folder-open-o" /></span>
+      <h2>暂无数据文件</h2>
+      <p>该数据集还没有可供预览的文件。</p>
+    </section>
   </PageCard>
 </template>
 
-<style scoped>
-.section-title {
+<style scoped lang="scss">
+.dataset-preview-page {
+  min-width: 0;
+}
+
+.page-heading {
+  display: flex;
+  align-items: center;
+  gap: 14px;
+  min-width: 0;
+}
+
+.heading-icon {
+  display: grid;
+  flex: 0 0 44px;
+  width: 44px;
+  height: 44px;
+  place-items: center;
+  border-radius: 12px;
+  background: linear-gradient(145deg, #eef2ff, #e0e7ff);
+  color: var(--primary-color);
+  font-size: 18px;
+}
+
+.heading-row {
+  display: flex;
+  align-items: center;
+  flex-wrap: wrap;
+  gap: 8px;
+}
+
+.heading-row h1 {
+  margin: 0 4px 0 0;
+  color: #172033;
+  font-size: 20px;
+  font-weight: 650;
+  line-height: 1.35;
+}
+
+.page-heading p {
+  margin: 4px 0 0;
+  color: #7c8799;
+  font-size: 13px;
+  line-height: 1.5;
+}
+
+.dataset-overview {
+  display: grid;
+  grid-template-columns: repeat(3, minmax(120px, 0.7fr)) minmax(220px, 1.2fr);
+  margin-bottom: 20px;
+  padding: 16px 20px;
+  border: 1px solid #edf0f5;
+  border-radius: 12px;
+  background: #fbfcfe;
+}
+
+.overview-item {
+  display: flex;
+  flex-direction: column;
+  gap: 5px;
+  min-width: 0;
+  padding: 0 20px;
+  border-right: 1px solid #e9edf4;
+}
+
+.overview-item:first-child {
+  padding-left: 0;
+}
+
+.overview-item:last-child {
+  padding-right: 0;
+  border-right: 0;
+}
+
+.overview-item span {
+  color: #8a94a6;
+  font-size: 12px;
+}
+
+.overview-item strong {
+  overflow: hidden;
+  color: #283347;
+  font-size: 15px;
+  font-variant-numeric: tabular-nums;
+  font-weight: 600;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.preview-workspace {
+  display: grid;
+  grid-template-columns: minmax(240px, 280px) minmax(0, 1fr);
+  min-height: 520px;
+  overflow: hidden;
+  border: 1px solid #e5eaf2;
+  border-radius: 12px;
+  background: #fff;
+}
+
+.file-pane {
+  display: flex;
+  flex-direction: column;
+  min-width: 0;
+  border-right: 1px solid #e5eaf2;
+  background: #f8fafc;
+}
+
+.pane-heading {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  min-height: 68px;
+  padding: 12px 16px;
+  border-bottom: 1px solid #e5eaf2;
+}
+
+.pane-eyebrow {
+  display: block;
+  margin-bottom: 2px;
+  color: #9aa4b5;
+  font-size: 10px;
+  font-weight: 700;
+  letter-spacing: 1.1px;
+}
+
+.pane-heading h2,
+.content-title h2 {
+  margin: 0;
+  color: #263146;
   font-size: 14px;
   font-weight: 600;
-  color: #606266;
-  margin: 0 0 12px;
 }
 
-.file-section {
-  margin-bottom: 24px;
-}
-
-.preview-pre {
-  margin: 0;
-  padding: 12px 16px;
-  background: #f5f7fa;
-  border: 1px solid #ebeef5;
-  border-radius: 4px;
-  font-family: 'SFMono-Regular', Consolas, monospace;
+.file-count {
+  display: grid;
+  min-width: 26px;
+  height: 26px;
+  place-items: center;
+  border-radius: 8px;
+  background: #e9edf4;
+  color: #596579;
   font-size: 12px;
-  line-height: 1.6;
-  max-height: 500px;
+  font-variant-numeric: tabular-nums;
+  font-weight: 600;
+}
+
+.file-list {
+  flex: 1;
+  min-height: 0;
+  overflow-y: auto;
+  padding: 8px;
+}
+
+.file-item {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  width: 100%;
+  min-height: 58px;
+  margin: 0 0 4px;
+  padding: 8px 10px;
+  border: 1px solid transparent;
+  border-radius: 9px;
+  background: transparent;
+  color: #526076;
+  cursor: pointer;
+  text-align: left;
+  transition: background-color 0.18s ease, border-color 0.18s ease, color 0.18s ease;
+}
+
+.file-item:hover {
+  border-color: #dce2eb;
+  background: #fff;
+}
+
+.file-item:focus-visible {
+  outline: 2px solid var(--el-color-primary-light-5);
+  outline-offset: 1px;
+}
+
+.file-item.is-active {
+  border-color: #cfd5ff;
+  background: #fff;
+  color: var(--primary-color);
+  box-shadow: 0 5px 16px rgba(79, 70, 229, 0.08);
+}
+
+.file-type {
+  display: grid;
+  flex: 0 0 42px;
+  height: 32px;
+  place-items: center;
+  border-radius: 7px;
+  background: #e9edf4;
+  color: #68758b;
+  font-size: 9px;
+  font-weight: 800;
+  letter-spacing: 0.35px;
+}
+
+.file-item.is-active .file-type {
+  background: #eef2ff;
+  color: var(--primary-color);
+}
+
+.file-copy {
+  display: flex;
+  flex: 1;
+  flex-direction: column;
+  gap: 3px;
+  min-width: 0;
+}
+
+.file-copy strong {
+  overflow: hidden;
+  font-size: 13px;
+  font-weight: 600;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.file-copy small {
+  color: #9aa4b5;
+  font-size: 11px;
+  font-variant-numeric: tabular-nums;
+}
+
+.content-pane {
+  display: flex;
+  flex-direction: column;
+  min-width: 0;
+  background: #fff;
+}
+
+.content-toolbar {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 16px;
+  min-height: 68px;
+  padding: 10px 16px;
+  border-bottom: 1px solid #e5eaf2;
+}
+
+.content-title {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  min-width: 0;
+}
+
+.content-title > div {
+  min-width: 0;
+}
+
+.content-title h2 {
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.content-title p {
+  display: flex;
+  gap: 6px;
+  margin: 3px 0 0;
+  color: #8a94a6;
+  font-size: 11px;
+  font-variant-numeric: tabular-nums;
+}
+
+.file-icon {
+  display: grid;
+  flex: 0 0 34px;
+  height: 34px;
+  place-items: center;
+  border-radius: 8px;
+  background: #f1f5f9;
+  color: #69768b;
+}
+
+.download-button {
+  min-height: 36px;
+}
+
+.download-button i {
+  margin-right: 6px;
+}
+
+.viewer-shell {
+  position: relative;
+  flex: 1;
+  min-height: 400px;
+  overflow: hidden;
+  background: #fbfcfe;
+}
+
+.code-viewer {
+  height: 100%;
+  max-height: 468px;
   overflow: auto;
-  white-space: pre-wrap;
-  word-wrap: break-word;
+  padding: 12px 0 18px;
+  outline: none;
 }
 
-.preview-footer {
-  margin-top: 8px;
+.code-viewer:focus-visible {
+  box-shadow: inset 0 0 0 2px var(--el-color-primary-light-5);
+}
+
+.code-line {
+  display: grid;
+  grid-template-columns: 54px minmax(0, 1fr);
+  min-height: 25px;
+  color: #344054;
+  font-family: 'SFMono-Regular', Consolas, 'Liberation Mono', monospace;
   font-size: 12px;
-  color: #909399;
+  line-height: 1.65;
+}
+
+.code-line:hover {
+  background: #f4f6fa;
+}
+
+.line-number {
+  padding-right: 14px;
+  border-right: 1px solid #edf0f5;
+  color: #a4adbc;
+  font-variant-numeric: tabular-nums;
+  text-align: right;
+  user-select: none;
+}
+
+.code-line code {
+  display: block;
+  min-width: max-content;
+  padding: 0 18px;
+  white-space: pre;
+}
+
+.viewer-state {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  flex-direction: column;
+  gap: 10px;
+  height: 100%;
+  min-height: 400px;
+  color: #8b96a8;
+  font-size: 13px;
+}
+
+.viewer-state > i {
+  color: #aeb7c5;
+  font-size: 24px;
+}
+
+.viewer-state-error > i,
+.viewer-state-error strong {
+  color: #d14343;
+}
+
+.viewer-state-error strong {
+  font-weight: 500;
+}
+
+.viewer-footer {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  min-height: 34px;
+  padding: 6px 14px;
+  border-top: 1px solid #e5eaf2;
+  background: #f8fafc;
+  color: #8a94a6;
+  font-size: 11px;
+}
+
+.viewer-footer i {
+  margin-right: 5px;
+}
+
+.empty-files {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  flex-direction: column;
+  min-height: 420px;
+  border: 1px dashed #dce2eb;
+  border-radius: 12px;
+  background: #fbfcfe;
   text-align: center;
 }
+
+.empty-icon {
+  display: grid;
+  width: 54px;
+  height: 54px;
+  margin-bottom: 14px;
+  place-items: center;
+  border-radius: 14px;
+  background: #eef2f7;
+  color: #8a96a8;
+  font-size: 22px;
+}
+
+.empty-files h2 {
+  margin: 0;
+  color: #354056;
+  font-size: 15px;
+}
+
+.empty-files p {
+  margin: 6px 0 0;
+  color: #929daf;
+  font-size: 13px;
+}
+
+@media (max-width: 900px) {
+  .dataset-overview {
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+    gap: 16px 0;
+  }
+
+  .overview-item:nth-child(2) {
+    border-right: 0;
+  }
+
+  .overview-item:nth-child(3) {
+    padding-left: 0;
+  }
+
+  .preview-workspace {
+    grid-template-columns: 220px minmax(0, 1fr);
+  }
+}
+
+@media (max-width: 680px) {
+  .dataset-overview {
+    grid-template-columns: 1fr;
+  }
+
+  .overview-item {
+    padding: 0 0 12px;
+    border-right: 0;
+    border-bottom: 1px solid #e9edf4;
+  }
+
+  .overview-item:last-child {
+    padding-bottom: 0;
+    border-bottom: 0;
+  }
+
+  .preview-workspace {
+    grid-template-columns: 1fr;
+  }
+
+  .file-pane {
+    max-height: 240px;
+    border-right: 0;
+    border-bottom: 1px solid #e5eaf2;
+  }
+
+  .content-toolbar {
+    align-items: flex-start;
+  }
+
+  .download-button {
+    width: 44px;
+    padding: 8px;
+    font-size: 0;
+  }
+
+  .download-button i {
+    margin: 0;
+    font-size: 14px;
+  }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .file-item {
+    transition: none;
+  }
+}
 </style>