fix：修复教师端考试管理入口被隐藏问题

src/views/teacher/AdminDashboard.vue

@@ -24,6 +24,45 @@
             <img :src="activeNavItem === 0 ? '/images/teacher/课程管理(选中).png' : '/images/teacher/课程管理.png'" alt="">
             <span>课程管理</span>
           </router-link>
+
+          <!-- 考试管理 - 可展开菜单 -->
+          <div class="nav-item" :class="{ active: activeNavItem === 4 }" @click="toggleExamMenu">
+            <img :src="activeNavItem === 4 ? '/images/teacher/练考通-选中.png' : '/images/teacher/练考通.png'" alt="">
+            <span>考试管理</span>
+            <n-icon class="expand-icon" :class="{ expanded: examMenuExpanded }">
+              <ChevronDownOutline />
+            </n-icon>
+          </div>
+          
+          <!-- 考试管理子菜单 -->
+          <div class="submenu-container" :class="{ expanded: examMenuExpanded }">
+            <router-link 
+              to="/teacher/exam-management/question-management" 
+              class="submenu-item" 
+              :class="{ active: activeSubNavItem === 'question-management' }"
+              @click="setActiveSubNavItem('question-management')"
+            >
+              <span>试题管理</span>
+            </router-link>
+            <router-link 
+              to="/teacher/exam-management/exam-library" 
+              class="submenu-item" 
+              :class="{ active: activeSubNavItem === 'exam-library' }"
+              @click="setActiveSubNavItem('exam-library')"
+            >
+              <span>试卷管理</span>
+            </router-link>
+            <router-link 
+              to="/teacher/exam-management/marking-center" 
+              class="submenu-item" 
+              :class="{ active: activeSubNavItem === 'marking-center' }"
+              @click="setActiveSubNavItem('marking-center')"
+            >
+              <span>阅卷中心</span>
+            </router-link>
+          </div>
+
+
           <router-link to="/teacher/student-management" class="nav-item" :class="{ active: activeNavItem === 1 }"
             @click="setActiveNavItem(1)">
 
@@ -66,6 +105,8 @@
 <script setup lang="ts">
 import { ref, onMounted, computed, watch } from 'vue'
 import { useRoute, useRouter } from 'vue-router'
+import { ChevronDownOutline } from '@vicons/ionicons5'
+
 
 const width = window.innerWidth;
 const height = window.innerHeight;
@@ -73,11 +114,36 @@ console.log(`当前屏幕宽度: ${width}px, 高度: ${height}px`);
 
 // 添加导航项激活状态管理
 const activeNavItem = ref(0); // 0: 课程管理, 1: 学员管理, 2: 我的资源, 3: 个人中心
+const activeSubNavItem = ref(''); // 子菜单激活状态
+const examMenuExpanded = ref(false); // 考试管理菜单展开状态
 const route = useRoute();
 const router = useRouter();
 
 const setActiveNavItem = (index: number) => {
   activeNavItem.value = index;
+  // 如果不是考试管理，关闭考试管理子菜单
+  if (index !== 4) {
+    examMenuExpanded.value = false;
+    activeSubNavItem.value = '';
+  }
+}
+
+// 考试管理菜单切换
+const toggleExamMenu = () => {
+  examMenuExpanded.value = !examMenuExpanded.value;
+  activeNavItem.value = 4;
+  
+  // 如果展开且没有选中子菜单，默认选中第一个
+  if (examMenuExpanded.value && !activeSubNavItem.value) {
+    activeSubNavItem.value = 'question-management';
+  }
+}
+
+// 设置子菜单激活状态
+const setActiveSubNavItem = (subItem: string) => {
+  activeSubNavItem.value = subItem;
+  activeNavItem.value = 4;
+  examMenuExpanded.value = true;
 }
 
 // 处理面包屑点击
@@ -226,6 +292,56 @@ const updateActiveNavItem = () => {
   overflow: hidden;
 }
 
+/* 展开图标样式 */
+.expand-icon {
+  margin-left: auto;
+  margin-right: 20px;
+  transition: transform 0.3s ease;
+  color: #666;
+}
+
+.expand-icon.expanded {
+  transform: rotate(180deg);
+}
+
+/* 子菜单容器 */
+.submenu-container {
+  overflow: hidden;
+  max-height: 0;
+  transition: max-height 0.3s ease-out;
+  margin-left: 20px;
+}
+
+.submenu-container.expanded {
+  max-height: 200px;
+}
+
+/* 子菜单项样式 */
+.submenu-item {
+  display: flex;
+  align-items: center;
+  height: 40px;
+  margin-bottom: 8px;
+  margin-left: 10px;
+  margin-right: 10px;
+  padding-left: 40px;
+  border-radius: 8px;
+  transition: all 0.3s ease;
+  text-decoration: none;
+  color: #666;
+  font-size: 16px;
+  position: relative;
+}
+
+.submenu-item:hover {
+  background: rgba(102, 183, 227, 0.05);
+}
+
+.submenu-item.active {
+  background: rgba(102, 183, 227, 0.1);
+  color: #0C99DA;
+}
+
 /* 响应式调整 */
 @media screen and (max-width: 768px) {
   .top-image-container {
@@ -395,6 +511,10 @@ const updateActiveNavItem = () => {
     width: 200px;
     margin: 0 10px 15px;
   }
+
+  .submenu-container{
+    width: 200px;
+  }
 }
 
 @media screen and (max-width: 480px) {
@@ -480,6 +600,23 @@ const updateActiveNavItem = () => {
   background-color: #0C99DA;
 }
 
+
+ @media screen and (max-width: 480px) {
+    .nav-container .nav-item {
+      width: 150px;
+      height: 45px;
+      margin: 0 5px 10px;
+    }
+  
+    .nav-container .nav-item img {
+      margin-left: 20px;
+    }
+
+    .submenu-container{
+      width: 150px;
+    }
+  }
+
 /* 可点击的面包屑项样式 */
 .breadcrumb :deep(.n-breadcrumb-item.clickable) {
   cursor: pointer;