fix(样式)：补充历史学习记录面板样式 + 修复缺失的 </style> 标签

- 新增 history-card/history-header/history-toggle/history-search/history-tabs/
  history-list/history-item/session-tag/history-content 等样式，
  与现有 fragments-card/fragment-item 等样式风格一致
- 之前 Edit 操作误删了文件末尾的 </style>，导致 Vue SFC 编译错误

src/components/StartTask.vue

@@ -641,9 +641,9 @@ onUnmounted(() => {
                 <span class="session-tag">{{ item.sessionNum }}</span>
                 <span class="history-content">{{ item.content }}</span>
               </div>
-              <el-empty v-if="!loadingHistory && historyFragments.length === 0" description="暂未找到匹配的残片" :image-size="48" />
+              <el-empty v-if="!loadingHistory && historyFragments.length === 0" description="暂未找到匹配的残片" :image-size="48"></el-empty>
             </div>
-            <el-pagination v-if="fragmentsTotal > 10" small layout="prev, pager, next" :total="fragmentsTotal" :page-size="10" :current-page="fragmentsPage" @current-change="onFragmentsPageChange" background />
+            <el-pagination v-if="fragmentsTotal > 10" small layout="prev, pager, next" :total="fragmentsTotal" :page-size="10" :current-page="fragmentsPage" @current-change="onFragmentsPageChange" background></el-pagination>
           </el-tab-pane>
           <el-tab-pane label="学习报告" name="reports">
             <div v-loading="loadingHistory" class="history-list">
@@ -954,4 +954,84 @@ onUnmounted(() => {
     width: 100%;
   }
 }
-</style>
+
+/* ---- 历史学习记录 ---- */
+.history-card {
+  padding: 20px;
+}
+
+.history-header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  cursor: pointer;
+  user-select: none;
+  gap: 10px;
+}
+
+.history-header-left {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+}
+
+.history-header-left h3 {
+  margin: 0;
+  font-size: 15px;
+  color: var(--green-900);
+}
+
+.history-toggle {
+  flex-shrink: 0;
+  font-size: 14px;
+  color: var(--green-700);
+  width: 18px;
+  text-align: center;
+}
+
+.history-search {
+  margin-top: 12px;
+}
+
+.history-tabs {
+  margin-top: 8px;
+}
+
+.history-list {
+  min-height: 60px;
+}
+
+.history-item {
+  display: flex;
+  align-items: flex-start;
+  gap: 10px;
+  padding: 10px 0;
+  border-bottom: 1px solid var(--border-soft);
+}
+
+.history-item:last-child {
+  border-bottom: none;
+}
+
+.session-tag {
+  flex-shrink: 0;
+  font-size: 11px;
+  color: var(--green-700);
+  background: #e8f5e9;
+  padding: 2px 8px;
+  border-radius: 4px;
+  white-space: nowrap;
+  font-weight: 600;
+}
+
+.history-content {
+  flex: 1;
+  font-size: 14px;
+  line-height: 1.6;
+  color: var(--text-primary);
+  word-break: break-word;
+}
+
+.report-item .history-content {
+  margin: 0;
+}</style>