feat: 综合大题改造（替代 Word 上传）+ MockExam 按组分支

中职/高职组以「综合大题」替代原 Word 文件上传：管理员在后台录入题干
（wangEditor 富文本，含表格），系统按组随机抽题，考生在 3 个小问内作答，
每小题 10 分、大题合计 30 分。

- api/admin.js / api/exam.js / stores/exam.js：大题题库 CRUD、抽题、作答与评分链路
- Competition.vue：Word 上传区块替换为大题作答区（3 小问 + 字数上限 + 富文本题干渲染）
- Admin.vue：大题题库管理、考生作答查看与人工评分
- MockExam.vue：按组分支——中职/高职显示综合大题，其余组保持 Word 答题；侧栏与提交提示同步
- RichEditor.vue + utils/richtext.js：题干富文本渲染前做白名单消毒（零依赖，纵深防御）

说明：big_questions / big_question_answers 建表迁移 023/024 随后端仓库提交。

src/views/Competition.vue

@@ -128,19 +128,24 @@
           </div>
         </div>
 
-        <!-- Word 答题 -->
-        <div class="nav-section" v-if="examStore.wordTemplate">
-          <div class="nav-section-title">Word 答题</div>
+        <!-- 综合大题（中职/高职，替代原 Word 上传题） -->
+        <div class="nav-section" v-if="examStore.bigQuestionEnabled">
+          <div class="nav-section-title">
+            综合大题
+            <span v-if="examStore.bigLoaded" class="nav-subcount">
+              （已答 {{ examStore.bigAnsweredCount }}/{{ examStore.bigSubCount }} 小问）
+            </span>
+          </div>
           <div class="question-nav">
             <div
               class="nav-item"
               :class="{
-                'nav-answered': wordUploaded || uploadedWordFile,
-                'nav-current': currentQuestionIndex === wordQuestionIndex,
+                'nav-answered': examStore.bigAllAnswered,
+                'nav-current': currentQuestionIndex === bigQuestionIndex,
               }"
-              @click="currentQuestionIndex = wordQuestionIndex"
+              @click="currentQuestionIndex = bigQuestionIndex"
             >
-              {{ wordQuestionIndex + 1 }}
+              {{ bigQuestionIndex + 1 }}
             </div>
           </div>
         </div>
@@ -159,7 +164,7 @@
       </div>
 
       <!-- 右侧题目区域 -->
-      <div class="exam-main" v-if="examStore.questions.length > 0">
+      <div class="exam-main" v-if="hasExamContent">
         <!-- 选择题 -->
         <div v-if="isCurrentChoice && currentQuestion.question_type === 'choice'" class="question-card">
           <div class="question-header">
@@ -224,75 +229,87 @@
           </div>
         </div>
 
-        <!-- Word 答题 -->
-        <div v-if="currentQuestionIndex === wordQuestionIndex" class="question-card word-card">
+        <!-- 综合大题（中职/高职）：题干富文本 + 三小问作答 -->
+        <div v-if="isCurrentBig" class="question-card big-card">
           <div class="question-header">
-            <span class="question-number">第 {{ wordQuestionIndex + 1 }} 题</span>
-            <el-tag type="danger" size="small">综合题</el-tag>
+            <span class="question-number">第 {{ bigQuestionIndex + 1 }} 题</span>
+            <el-tag type="danger" size="small">综合大题</el-tag>
+            <span class="question-score" v-if="examStore.bigLoaded">
+              （每小题 {{ examStore.bigScorePerSub }} 分，共 {{ examStore.bigTotalScore }} 分）
+            </span>
           </div>
-          <div class="question-body">
-            <p class="question-text">请下载 Word 答题模板，在 Word 中完成答题后上传。</p>
 
-            <div class="word-sections">
-              <!-- 下载区域 -->
-              <div class="word-section">
-                <h4>第 1 步：下载模板</h4>
-                <el-button
-                  type="primary"
-                  :icon="Download"
-                  v-guard="() => downloadTemplate()"
-                  :loading="wordDownloading"
-                >
-                  下载 Word 答题模板
-                </el-button>
+          <!-- 加载中 -->
+          <div class="question-body" v-if="examStore.bigLoading">
+            <el-skeleton :rows="5" animated />
+          </div>
 
-                <div v-if="wordDownloading" class="word-progress">
-                  <el-progress :percentage="wordDownloadPercent" />
-                </div>
-              </div>
-
-              <el-divider />
-
-              <!-- 上传区域 -->
-              <div class="word-section">
-                <h4>第 2 步：上传答卷</h4>
-                <el-upload
-                  class="word-upload"
-                  drag
-                  :auto-upload="false"
-                  :limit="1"
-                  :on-change="onWordFileChange"
-                  :file-list="wordFileList"
-                  accept=".doc,.docx"
-                >
-                  <el-icon class="el-icon--upload" :size="36"><UploadFilled /></el-icon>
-                  <div class="el-upload__text">
-                    拖拽或 <em>点击上传</em> Word 文件
-                  </div>
-                  <template #tip>
-                    <div class="el-upload__tip">仅支持 .doc / .docx 文件</div>
-                  </template>
-                </el-upload>
-
-                <div v-if="wordUploading" class="word-progress">
-                  <el-progress :percentage="wordUploadPercent" />
-                </div>
-
-                <div v-if="uploadedWordFile" class="uploaded-info">
-                  <el-tag type="success" size="small">已上传</el-tag>
-                  <span class="uploaded-name">{{ uploadedWordFile.fileName }}</span>
-                  <span class="uploaded-size">{{ uploadedWordFile.fileSize }}</span>
-                  <el-button
-                    size="small"
-                    type="danger"
-                    plain
-                    :loading="wordDeleting"
-                    v-guard="() => deleteWordFile()"
-                  >删除并重新上传</el-button>
-                </div>
-              </div>
+          <!-- 抽题失败：给出明确原因与重试入口（不静默留白） -->
+          <div class="question-body" v-else-if="!examStore.bigLoaded">
+            <el-alert
+              type="error"
+              :closable="false"
+              show-icon
+              :title="examStore.bigError || '综合大题加载失败'"
+              description="若提示「该组别暂无大题」，请联系监考老师；若为网络问题，可点击下方按钮重试。"
+            />
+            <div class="big-retry">
+              <el-button type="primary" :loading="examStore.bigLoading" v-guard="() => retryBigQuestion()">
+                重新加载题目
+              </el-button>
             </div>
           </div>
+
+          <!-- 题干 + 三小问作答 -->
+          <div class="question-body" v-else>
+            <h3 class="big-title">{{ examStore.bigQuestion.title }}</h3>
+
+            <!-- 富文本题干（含表格）：经白名单消毒后渲染 -->
+            <div class="big-description" v-html="bigDescriptionHtml"></div>
+
+            <el-alert
+              v-if="!examStore.bigAllAnswered"
+              class="big-hint"
+              type="info"
+              :closable="false"
+              show-icon
+              title="请在下方三个输入框中分别作答，每个输入框最多 2000 字，作答内容会实时自动保存。"
+            />
+
+            <div
+              v-for="i in examStore.bigSubCount"
+              :key="i"
+              class="big-sub-item"
+            >
+              <div class="big-sub-header">
+                <span class="big-sub-no">第 {{ i }} 小问</span>
+                <span class="big-sub-score">（{{ examStore.bigScorePerSub }} 分）</span>
+              </div>
+              <div v-if="examStore.bigSubPrompts[i - 1]" class="big-sub-prompt">{{ examStore.bigSubPrompts[i - 1] }}</div>
+              <el-input
+                class="big-answer-input"
+                type="textarea"
+                :rows="6"
+                resize="vertical"
+                :maxlength="examStore.bigMaxChars"
+                show-word-limit
+                :placeholder="`请输入第 ${i} 小问的答案（最多 ${examStore.bigMaxChars} 字）`"
+                :model-value="bigAnswerOf(i)"
+                @update:model-value="val => onBigAnswerInput(i, val)"
+              />
+            </div>
+
+            <!-- 保存状态：让考生对「是否已存上」有明确反馈 -->
+            <div class="big-save-status">
+              <el-tag v-if="examStore.bigSaving" size="small" type="warning" effect="plain">正在保存…</el-tag>
+              <el-tag v-else-if="bigSaveErrorShown" size="small" type="danger" effect="plain">
+                保存失败：{{ examStore.bigError }}
+              </el-tag>
+              <el-tag v-else size="small" type="success" effect="plain">已自动保存</el-tag>
+              <span class="big-save-note">已答 {{ examStore.bigAnsweredCount }}/{{ examStore.bigSubCount }} 小问</span>
+            </div>
+          </div>
+
           <div class="question-footer">
             <el-button :disabled="currentQuestionIndex === 0" @click="prevQuestion">上一题</el-button>
             <el-button v-if="currentQuestionIndex < totalCount - 1" type="primary" @click="nextQuestion">
@@ -312,7 +329,9 @@
     <div class="exam-bottom-bar" v-if="!isUploadMode">
       <div class="exam-bottom-inner">
         <span class="submit-hint">
-          请确保已检查所有题目和 Word 文件后提交
+          {{ examStore.bigQuestionEnabled
+            ? `请确保已检查所有题目和综合大题（已答 ${examStore.bigAnsweredCount}/${examStore.bigSubCount} 小问）后提交`
+            : '请确保已检查所有题目后提交' }}
         </span>
         <el-button
           type="danger"
@@ -343,12 +362,13 @@
 import { ref, computed, onMounted, onUnmounted, watch } from 'vue'
 import { useRouter, onBeforeRouteLeave } from 'vue-router'
 import { ElMessage, ElMessageBox, ElNotification } from 'element-plus'
-import { Timer, Download, UploadFilled } from '@element-plus/icons-vue'
+import { Timer, UploadFilled } from '@element-plus/icons-vue'
 import { useAuthStore } from '@/stores/auth'
 import { useExamStore } from '@/stores/exam'
 import * as examApi from '@/api/exam'
 import * as uploadApi from '@/api/upload'
 import { formatFileSize } from '@/utils/upload'
+import { sanitizeHtml } from '@/utils/richtext'
 import {
   fileExt,
   categoryOf,
@@ -374,7 +394,6 @@ const uploadRef = ref(null)
 
 const ZIP_MAX = 200 * 1024 * 1024
 const OTHER_MAX = 100 * 1024 * 1024
-const WORD_MAX = 50 * 1024 * 1024 // 与后端 uploadWord 服务端 50MB 上限一致
 
 function fileTypeOf(name) {
   const e = '.' + fileExt(name)
@@ -509,32 +528,45 @@ const loading = ref(true)
 const submitting = ref(false)
 const currentQuestionIndex = ref(0)
 
-// Word 上传相关
-const wordFileList = ref([])
-const wordUploading = ref(false)
-const wordUploadPercent = ref(0)
-const wordDeleting = ref(false)
-const uploadedWordFile = ref(null)
-const wordDownloading = ref(false)
-const wordDownloadPercent = ref(0)
-const wordUploaded = ref(false)
-
 // ==================== 计算属性 ====================
 
+// 综合大题作为最后一道「题」参与导航与题量统计（中职/高职启用，本科/教师不启用）
 const totalCount = computed(() => {
   const base = examStore.questions.length
-  return examStore.wordTemplate ? base + 1 : base
+  return examStore.bigQuestionEnabled ? base + 1 : base
 })
 
-// Word 题目的虚拟索引（最后一个）
-const wordQuestionIndex = computed(() => examStore.questions.length)
+// 综合大题的虚拟索引（最后一个）
+const bigQuestionIndex = computed(() => examStore.questions.length)
+
+// 当前是否停在综合大题
+const isCurrentBig = computed(() => {
+  return examStore.bigQuestionEnabled && currentQuestionIndex.value === bigQuestionIndex.value
+})
+
+// 右侧题目区是否有内容可渲染（客观题与综合大题任一可用即渲染，避免只抽到大题时误显示空状态）
+const hasExamContent = computed(() => {
+  return examStore.questions.length > 0 || (examStore.bigQuestionEnabled && examStore.bigLoaded)
+})
 
 const answeredCount = computed(() => {
   let count = Object.keys(examStore.answers).length
-  if (wordUploaded.value || uploadedWordFile.value) count++
+  // 综合大题按「三小问全部作答」计为 1 题已答（部分作答可在侧栏看到 x/3 明细）
+  if (examStore.bigQuestionEnabled && examStore.bigAllAnswered) count++
   return count
 })
 
+/** 题干富文本：白名单消毒后再交给 v-html 渲染 */
+const bigDescriptionHtml = computed(() => {
+  const q = examStore.bigQuestion
+  return sanitizeHtml((q && q.description) || '')
+})
+
+/** 是否处于「保存失败」状态（保存中优先展示加载态，失败时给出明确提示） */
+const bigSaveErrorShown = computed(() => {
+  return !examStore.bigSaving && !!examStore.bigError && examStore.bigLoaded
+})
+
 const remainingSeconds = computed(() => examStore.countdown)
 
 const progressPercent = computed(() => {
@@ -625,170 +657,56 @@ function nextQuestion() {
   }
 }
 
-// ==================== Word 相关 ====================
+// ==================== 综合大题（中职/高职） ====================
 
-/** 下载 Word 模板 */
-async function downloadTemplate() {
-  if (!examStore.wordTemplate?.group) return
-  const token = localStorage.getItem('token')
-  const url = `/api/exam/${examStore.wordTemplate.group}/word-template?token=${encodeURIComponent(token || '')}`
+/** 取第 index 小问的当前答案（空值统一为 ''，避免 el-input 出现 undefined 告警） */
+function bigAnswerOf(index) {
+  const v = examStore.bigAnswers[`answer_${index}`]
+  return v == null ? '' : v
+}
 
-  wordDownloading.value = true
-  wordDownloadPercent.value = 0
-  try {
-    // 同时带上 Authorization 请求头（与上传一致），确保 auth 校验通过
-    const headers = token ? { Authorization: `Bearer ${token}` } : undefined
-    const response = await fetch(url, headers ? { headers } : undefined)
-    const contentType = response.headers.get('content-type') || ''
+/** 输入即写本地 + 防抖自动保存（落库由 store 统一处理） */
+function onBigAnswerInput(index, value) {
+  examStore.setBigAnswer(index, value)
+}
 
-    if (contentType.includes('application/json')) {
-      const data = await response.json()
-      if (data.code !== 0) {
-        ElMessage.warning(data.message || '模板下载失败')
-        return
-      }
-    }
-
-    if (!response.ok) {
-      ElMessage.error('模板下载失败')
-      return
-    }
-
-    const disposition = response.headers.get('content-disposition')
-    let filename = 'template.docx'
-    if (disposition) {
-      const match = disposition.match(/filename\*?=(?:UTF-8''|"?)([^";]+)/i)
-      if (match) {
-        filename = decodeURIComponent(match[1])
-      }
-    }
-
-    // 🔴 流式读取，实时更新下载进度（1M 带宽下大文件较慢，必须有反馈，
-    // 消除「点击后无反应」的错觉，与上传进度体验一致）。
-    const reader = response.body.getReader()
-    const contentLength = parseInt(response.headers.get('content-length') || '0', 10)
-    let received = 0
-    const chunks = []
-    while (true) {
-      const { done, value } = await reader.read()
-      if (done) break
-      chunks.push(value)
-      received += value.length
-      if (contentLength > 0) {
-        wordDownloadPercent.value = Math.min(99, Math.floor((received / contentLength) * 100))
-      } else {
-        // 无 content-length（被分块/压缩）时给一个随已下载量缓增的估算进度，封顶 95
-        wordDownloadPercent.value = Math.min(95, Math.floor((received / (5 * 1024 * 1024)) * 100))
-      }
-    }
-    const blob = new Blob(chunks)
-
-    // 🔴 同源守卫（2026-08-13 推进 #12 / 同源扩大化测试）：本函数走裸 fetch，
-    // 不经过 safeDownload/fetchBlobGuarded 的 assertRealFile。若 nginx /internal-downloads/
-    // 内部 location 未生效而回退吐 index.html(text/html)，原逻辑会把 HTML 当 .docx/.pptx
-    // 存盘 → 打开「已损坏」。这里补同样的 HTML 嗅探 + X-File-Size 大小比对，命中即拒存盘。
-    const head = await blob.slice(0, 256).text().catch(() => '');
-    if (/^\s*(<!doctype\s+html|<html[\s>])/i.test(head)) {
-      ElMessage.error('服务器返回的是网页而非模板文件，下载通道配置异常（请联系管理员检查 nginx 内部下载 location）');
-      return;
-    }
-    const declared = parseInt(response.headers.get('x-file-size') || response.headers.get('content-length') || '0', 10);
-    if (Number.isFinite(declared) && declared > 0 && received !== declared) {
-      ElMessage.error(`模板传输不完整：应为 ${declared} 字节，实际 ${received} 字节，请重试`);
-      return;
-    }
-
-    wordDownloadPercent.value = 100
-    const downloadUrl = window.URL.createObjectURL(blob)
-    const link = document.createElement('a')
-    link.href = downloadUrl
-    link.download = filename
-    document.body.appendChild(link)
-    link.click()
-    document.body.removeChild(link)
-    window.URL.revokeObjectURL(downloadUrl)
-  } catch (err) {
-    ElMessage.error('模板下载失败')
-  } finally {
-    wordDownloading.value = false
+/** 抽题/加载失败后的手动重试 */
+async function retryBigQuestion() {
+  const ok = await examStore.loadBigQuestion(examStore.currentGroup)
+  if (ok) {
+    ElMessage.success('综合大题已加载')
+  } else {
+    ElMessage.error(examStore.bigError || '综合大题加载失败')
   }
 }
 
-/** Word 文件选择变化 */
-function onWordFileChange(file) {
-  const raw = file.raw || file
-  // 客户端先行校验大小（与后端 uploadWord 50MB 上限一致），超限直接拦截并给出带文件大小的明确提示
-  if (raw.size > WORD_MAX) {
-    ElMessage.error(`Word 文件「${raw.name}」大小为 ${formatFileSize(raw.size)}，超过 50MB 限制，无法上传`)
-    wordFileList.value = []
-    return
-  }
-  wordFileList.value = [file]
-  uploadWordFile()
-}
-
-/** 上传 Word 文件 */
-async function uploadWordFile() {
-  if (wordFileList.value.length === 0) return null
-  const rawFile = wordFileList.value[0]?.raw || wordFileList.value[0]
-  if (!rawFile) return null
-
-  wordUploading.value = true
-  wordUploadPercent.value = 0
-  try {
-    const formData = new FormData()
-    formData.append('file', rawFile)
-
-    const result = await examApi.uploadWord(examStore.currentGroup, formData)
-    wordUploadPercent.value = 100
-    wordUploaded.value = true
-
-    uploadedWordFile.value = {
-      fileName: rawFile.name,
-      fileSize: formatFileSize(rawFile.size),
-      md5: result?.md5 || '',
-    }
-    return result
-  } catch (err) {
-    ElMessage.error('Word 文件上传失败')
-    return null
-  } finally {
-    wordUploading.value = false
-  }
-}
-
-/** 删除已上传的 Word 文件（支持重新上传替换） */
-async function deleteWordFile() {
-  try {
-    await ElMessageBox.confirm(
-      '确定要删除已上传的 Word 文件吗？删除后可重新上传进行替换。',
-      '删除确认',
-      { confirmButtonText: '确认删除', cancelButtonText: '取消', type: 'warning' }
-    )
-  } catch {
-    return
-  }
-
-  wordDeleting.value = true
-  try {
-    await examApi.deleteWord(examStore.currentGroup)
-    uploadedWordFile.value = null
-    wordFileList.value = []
-    wordUploaded.value = false
-    ElMessage.success('Word 文件已删除，可重新上传')
-  } catch (err) {
-    ElMessage.error(err?.response?.data?.message || '删除失败，请重试')
-  } finally {
-    wordDeleting.value = false
+/**
+ * 交卷前确保综合大题答案已落库
+ * @param {{force?: boolean}} [opts]
+ * @returns {Promise<boolean>} 是否落库成功
+ */
+async function ensureBigAnswersSaved(opts = {}) {
+  if (!examStore.bigQuestionEnabled || !examStore.bigLoaded) return true
+  const r = await examStore.flushBigAnswers(opts)
+  if (!r.ok) {
+    ElMessage.error(`综合大题答案保存失败：${r.message || '请检查网络后重试'}`)
+    return false
   }
+  return true
 }
 
 // ==================== 提交全部 ====================
 
 async function handleSubmitAll() {
+  // 未答满时给出明确的「还差什么」，避免考生误交卷
+  let confirmText = '确定要提交全部答案吗？提交后将无法修改，请确保所有题目已作答完成。'
+  if (examStore.bigQuestionEnabled && examStore.bigLoaded && !examStore.bigAllAnswered) {
+    const lack = examStore.bigSubCount - examStore.bigAnsweredCount
+    confirmText = `综合大题还有 ${lack} 个小问未作答，提交后将无法修改。确定要提交全部答案吗？`
+  }
   try {
     await ElMessageBox.confirm(
-      '确定要提交全部答案吗？提交后将无法修改，请确保所有题目已作答完成。',
+      confirmText,
       '确认提交',
       { confirmButtonText: '确认提交', cancelButtonText: '再检查一下', type: 'warning' }
     )
@@ -798,16 +716,11 @@ async function handleSubmitAll() {
 
   submitting.value = true
   try {
-    if (wordFileList.value.length > 0 && !uploadedWordFile.value) {
-      await uploadWordFile()
-    }
+    // 先把综合大题答案落库（submit-all 只处理客观题与提交时间），失败即中止交卷
+    const saved = await ensureBigAnswersSaved()
+    if (!saved) return
 
-    const additionalData = {}
-    if (uploadedWordFile.value) {
-      additionalData.wordFile = uploadedWordFile.value
-    }
-
-    await examStore.submitAll(additionalData)
+    await examStore.submitAll({})
     ElMessage.success('提交成功！')
   } catch (err) {
     if (err?.message) ElMessage.error(err.message)
@@ -841,19 +754,17 @@ async function autoSubmit() {
   }
   ElMessage.warning('考试时间已到，系统将自动保存并提交您的答案')
   try {
-    // 若尚有未上传的 Word 答题文件，先上传，避免作品被遗漏
-    if (wordFileList.value.length > 0 && !uploadedWordFile.value) {
-      await uploadWordFile()
-    }
-    const additionalData = {}
-    if (uploadedWordFile.value) {
-      additionalData.wordFile = uploadedWordFile.value
-    }
     // forceSubmit：倒计时归零即合法交卷，绕过「未答满全部题目 / 窗口已关闭」闸门，
-    // 确保 submit_time 落库（管理后台提交时间显示为真实交卷时间，而非进入考试时间）。
-    additionalData.forceSubmit = true
-    // submitAll 内部会逐题保存答案并写入提交时间，完成「自动保存 + 自动提交」
-    await examStore.submitAll(additionalData)
+    // 确保最后输入的大题答案与 submit_time 都能落库（管理后台显示真实交卷时间）。
+    const saved = await ensureBigAnswersSaved({ force: true })
+    if (!saved) {
+      // 落库失败不退化为静默丢答案：提示考生手动重试
+      ElMessage.error('综合大题答案未能保存，请点击「提交全部」重试')
+      autoSubmitted.value = false
+      return
+    }
+    // submitAll 内部会逐题保存客观题答案并写入提交时间（大题已在上面落库）
+    await examStore.submitAll({ forceSubmit: true })
     ElMessage.success('已自动保存并提交')
     router.push('/dashboard')
   } catch (err) {
@@ -927,27 +838,44 @@ function handleBeforeUnload(e) {
   }
 }
 
-// 禁止复制
+/**
+ * 事件目标是否为「可编辑元素」（综合大题的作答输入框）
+ *
+ * 考试页为保证题目不被外传，全局禁用了选中/复制/右键。但综合大题要求考生
+ * 在输入框内自行作答，若沿用同一套拦截会导致无法选中、修改、粘贴自己写的内容。
+ * 因此对可编辑元素做最小豁免：只放行「编辑自身答案」所需的操作，
+ * 题目区域（非可编辑）的防护行为完全不变。
+ */
+function isEditableTarget(e) {
+  const el = e && e.target
+  if (!el) return false
+  const tag = (el.tagName || '').toLowerCase()
+  return tag === 'textarea' || tag === 'input' || el.isContentEditable === true
+}
+
+// 禁止复制（可编辑元素内放行，否则考生无法复制/粘贴自己的作答）
 function preventCopy(e) {
+  if (isEditableTarget(e)) return
   e.preventDefault()
   return false
 }
 
-// 禁止鼠标选中文字
+// 禁止鼠标选中文字（可编辑元素内放行，否则输入框内无法选中文字）
 function preventSelect(e) {
+  if (isEditableTarget(e)) return
   e.preventDefault()
   return false
 }
 
 // 禁止键盘快捷键：Ctrl+C、Ctrl+U、F12、Ctrl+Shift+I、Ctrl+Shift+C、Ctrl+Shift+J
 function preventKeyboard(e) {
-  // F12（开发者工具）
+  // F12（开发者工具）—— 任何位置均拦截
   if (e.key === 'F12' || e.keyCode === 123) {
     e.preventDefault()
     return false
   }
 
-  // Ctrl+Shift+I / Ctrl+Shift+C / Ctrl+Shift+J（开发者工具）
+  // Ctrl+Shift+I / Ctrl+Shift+C / Ctrl+Shift+J（开发者工具）—— 任何位置均拦截
   if (e.ctrlKey && e.shiftKey) {
     if (e.key === 'I' || e.key === 'i' ||
         e.key === 'C' || e.key === 'c' ||
@@ -957,6 +885,9 @@ function preventKeyboard(e) {
     }
   }
 
+  // 以下剪贴/保存/打印类快捷键：仅在可编辑元素内放行（考生编辑自身答案所需）
+  if (isEditableTarget(e)) return
+
   // Ctrl+C（复制）
   if (e.ctrlKey && (e.key === 'C' || e.key === 'c' || e.keyCode === 67)) {
     e.preventDefault()
@@ -1072,8 +1003,9 @@ onMounted(async () => {
 
       await examStore.startExam(group)
 
-      if (examStore.questions.length === 0) {
-        ElMessage.error('题目加载失败，请刷新页面重试')
+      // 客观题与综合大题都为空才算加载失败；只抽到大题（客观题库为空）时仍可正常作答
+      if (examStore.questions.length === 0 && !examStore.bigLoaded) {
+        ElMessage.error(examStore.bigError || '题目加载失败，请刷新页面重试')
         router.push('/dashboard')
         return
       }
@@ -1350,26 +1282,116 @@ onUnmounted(() => {
   border-top: 1px solid #ebeef5;
 }
 
-/* ==================== Word 答题卡片 ==================== */
-.word-card .word-sections {
-  display: flex;
-  flex-direction: column;
-  gap: 0.5rem;
-}
-.word-section {
-  padding: 0.5rem 0;
-}
-.word-section h4 {
-  font-size: 0.95rem;
+/* ==================== 综合大题卡片 ==================== */
+.big-card .big-title {
+  font-size: 1.05rem;
   font-weight: 600;
+  color: #303133;
   margin: 0 0 0.75rem 0;
+  line-height: 1.6;
+}
+
+/* 富文本题干：scoped CSS 不作用于 v-html 子节点，须用 :deep() 兜底可读性 */
+.big-description {
+  font-size: 0.95rem;
+  line-height: 1.8;
+  color: #303133;
+  margin-bottom: 1rem;
+  word-break: break-word;
+}
+.big-description :deep(p) {
+  margin: 0.4rem 0;
+}
+.big-description :deep(table) {
+  width: 100%;
+  border-collapse: collapse;
+  margin: 0.75rem 0;
+  font-size: 0.9rem;
+}
+.big-description :deep(th),
+.big-description :deep(td) {
+  border: 1px solid #dcdfe6;
+  padding: 0.5rem 0.65rem;
+  text-align: left;
+  vertical-align: top;
+}
+.big-description :deep(th) {
+  background: #f5f7fa;
+  font-weight: 600;
+}
+.big-description :deep(img) {
+  max-width: 100%;
+  height: auto;
+}
+
+.big-hint {
+  margin-bottom: 1rem;
+}
+
+.big-sub-item {
+  margin-top: 1.25rem;
+  padding-top: 1rem;
+  border-top: 1px dashed #ebeef5;
+}
+.big-sub-header {
+  display: flex;
+  align-items: center;
+  gap: 0.5rem;
+  margin-bottom: 0.4rem;
+}
+.big-sub-no {
+  font-weight: 600;
   color: #303133;
 }
-.word-upload {
-  width: 100%;
+.big-sub-score {
+  font-size: 0.85rem;
+  color: #909399;
 }
-.word-progress {
-  margin-top: 0.75rem;
+.big-sub-prompt {
+  font-size: 0.9rem;
+  color: #606266;
+  line-height: 1.7;
+  margin-bottom: 0.5rem;
+  /* 小题提示为纯文本，保留换行与缩进 */
+  white-space: pre-wrap;
+  word-break: break-word;
+}
+
+/* 作答输入框：考试页全局禁用选中，这里必须恢复，否则考生无法编辑自己的答案 */
+.big-answer-input :deep(.el-textarea__inner) {
+  -webkit-user-select: text;
+  -moz-user-select: text;
+  -ms-user-select: text;
+  user-select: text;
+  font-size: 0.95rem;
+  line-height: 1.7;
+}
+/* 字数统计（el-input show-word-limit 默认渲染在右下角） */
+.big-answer-input :deep(.el-input__count) {
+  background: transparent;
+  color: #909399;
+  font-size: 0.8rem;
+}
+
+.big-save-status {
+  display: flex;
+  align-items: center;
+  gap: 0.75rem;
+  margin-top: 1rem;
+}
+.big-save-note {
+  font-size: 0.85rem;
+  color: #909399;
+}
+.big-retry {
+  margin-top: 1rem;
+}
+
+/* 侧栏综合大题小问计数 */
+.nav-subcount {
+  font-size: 0.8rem;
+  color: #909399;
+  font-weight: 400;
 }
 .uploaded-info {
   display: flex;