:root {
      --primary-color: #2c3e50;
      --secondary-color: #3498db;
      --text-color: #ecf0f1;
      --hover-color: #2980b9;
      --dropdown-bg: #ffffff;
      --mobile-bg: #1a252f;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
      padding-top: 70px;
      /* 为固定导航栏留出空间 */
    }

    /* 导航栏基础样式 */
    .navbar {
      display: flex;
      justify-content: space-between;
      align-items: center;
      background-color: var(--primary-color);
      padding: 0 30px;
      height: 70px;
      position: fixed;
      top: 0;
      left: 0;
      right: 0;
      z-index: 1000;
      box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    }

    .logo {
      color: var(--text-color);
      font-size: 1.5rem;
      font-weight: bold;
      text-decoration: none;
      display: flex;
      align-items: center;
      height: 100%;
      padding: 0 15px;
    }

    /* 主导航链接 */
    .nav-links {
      display: flex;
      list-style: none;
    }

    .nav-links li {
      position: relative;
    }

    .nav-links>li>a {
      color: var(--text-color);
      text-decoration: none;
      padding: 0 15px;
      height: 70px;
      display: flex;
      align-items: center;
      transition: all 0.3s ease;
    }

    .nav-links>li>a:hover {
      background-color: rgba(255, 255, 255, 0.1);
      color: var(--text-color);
    }

    /* 下拉菜单 */
    .dropdown {
      position: relative;
    }

    .dropdown-content {
      display: none;
      position: absolute;
      top: 100%;
      left: 0;
      background-color: var(--dropdown-bg);
      min-width: 200px;
      box-shadow: 0 8px 16px rgba(0, 0, 0, 0.1);
      border-radius: 0 0 5px 5px;
      overflow: hidden;
      z-index: 1001;
      opacity: 0;
      transform: translateY(-10px);
      transition: all 0.3s ease;
    }

    .dropdown:hover .dropdown-content {
      display: block;
      opacity: 1;
      transform: translateY(0);
    }

    .dropdown-content a {
      color: var(--primary-color);
      padding: 12px 20px;
      display: block;
      text-decoration: none;
      transition: all 0.2s ease;
    }

    .dropdown-content a:hover {
      background-color: #f5f5f5;
      padding-left: 25px;
    }

    /* 搜索框 */
    .search-container {
      display: flex;
      align-items: center;
      margin-left: 20px;
    }

    .search-input {
      padding: 10px 15px;
      border: none;
      border-radius: 20px 0 0 20px;
      outline: none;
      width: 200px;
      transition: width 0.3s ease;
    }

    .search-input:focus {
      width: 250px;
    }

    .search-btn {
      padding: 10px 15px;
      background-color: var(--secondary-color);
      color: white;
      border: none;
      border-radius: 0 20px 20px 0;
      cursor: pointer;
      transition: background-color 0.3s ease;
    }

    .search-btn:hover {
      background-color: var(--hover-color);
    }

    /* 汉堡菜单 */
    .hamburger {
      display: none;
      cursor: pointer;
      padding: 15px;
    }

    .hamburger div {
      width: 25px;
      height: 3px;
      background-color: var(--text-color);
      margin: 5px 0;
      transition: all 0.3s ease;
    }

    /* 移动导航菜单 */
    .mobile-nav {
      display: none;
      width: 100%;
      background-color: var(--mobile-bg);
      position: absolute;
      top: 70px;
      left: 0;
      z-index: 999;
      box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.5s ease;
    }

    .mobile-nav.active {
      display: block;
      max-height: 500px;
    }

    .mobile-nav li {
      border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }

    .mobile-nav a {
      color: var(--text-color);
      text-decoration: none;
      padding: 15px 30px;
      display: block;
      transition: all 0.3s ease;
    }

    .mobile-nav a:hover {
      background-color: rgba(255, 255, 255, 0.1);
      padding-left: 35px;
    }

    .mobile-dropdown-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.5s ease;
      background-color: rgba(0, 0, 0, 0.1);
    }

    .mobile-dropdown-content.active {
      max-height: 300px;
    }

    .mobile-dropdown-content a {
      padding-left: 45px;
    }

    /* 响应式设计 */
    @media (max-width: 992px) {

      .nav-links,
      .search-container {
        display: none;
      }

      .hamburger {
        display: block;
      }

      /* 汉堡菜单动画 */
      .hamburger.active div:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
      }

      .hamburger.active div:nth-child(2) {
        opacity: 0;
      }

      .hamburger.active div:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
      }
    }

    /* 小屏幕搜索框 */
    @media (max-width: 576px) {
      .search-container {
        width: 100%;
        margin: 15px 0;
      }

      .search-input {
        width: 100%;
      }

      .search-input:focus {
        width: 100%;
      }
    }