html {
    font-size: 16px;
  }
  
  @media (max-width: 1200px) {
    html { font-size: 14px; }
  }
  @media (max-width: 900px) {
    html { font-size: 12px; }
  }
  @media (max-width: 600px) {
    html { font-size: 10px; }
  }
  
  /* 顶部导航栏整体背景 */
  .nav-header {
      display: flex;
      align-items: center;
      height: 4.375rem;
      padding: 0 2.5rem;
      font-family: 'Microsoft YaHei', Arial, sans-serif;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1111;
      background: rgba(34, 34, 34, 0.82); /* 深色半透明背景 */
      border-bottom: none;
      box-shadow: 0 2px 12px rgba(0,0,0,0.10);
      box-sizing: border-box;
  }
  body {
      padding-top: 4.375rem;
  }
    
    /* LOGO区域 */
    .nav-logo {
      flex: 0 0 auto;
      margin-right: 1.2rem;
      height: 3.75rem;
      display: flex;
      align-items: center;
    }
    .nav-logo img {
      height: 3rem;
      width: auto;
      filter: drop-shadow(0 1px 4px rgba(0,0,0,0.18));
    }
    
    /* 一级菜单 */
    .nav-menu {
      display: flex;
      flex: 1;
      list-style: none;
      margin: 0;
      padding: 0;
    }
    .nav-menu-item {
      position: relative;
      margin: 0 0.4rem;
      display: flex;
      align-items: center;
      height: 4.375rem;
    }
    .nav-menu-item > a {
      display: flex;
      align-items: center;
      color: #fff;
      font-size: 0.875rem;
      font-weight: normal;
      padding: 0 0.75rem;
      height: 100%;
      text-decoration: none;
      transition: color 0.2s, font-weight 0.2s, background 0.2s;
      position: relative;
      overflow: hidden;
      text-shadow: 0 1px 4px rgba(0,0,0,0.18);
    }
    .nav-menu-item > a::after {
      content: '';
      display: block;
      position: absolute;
      left: 50%;
      bottom: 0.5rem;
      width: 0;
      height: 3px;
      background: #fff;
      border-radius: 2px;
      transition: width 0.35s cubic-bezier(.4,0,.2,1), left 0.35s cubic-bezier(.4,0,.2,1);
    }
    .nav-menu-item:hover > a,
    .nav-menu-item-active > a {
      color: #ffd700;
      background: none;
      border-bottom: none;
      text-shadow: 0 2px 8px rgba(0,0,0,0.22);
    }
    .nav-menu-item:hover > a::after,
    .nav-menu-item-active > a::after {
      width: 60%;
      left: 20%;
    }
    
    /* 图标预留位 */
    .nav-icon {
      display: inline-flex;
      align-items: center;
      margin-right: 0.5rem;
      width: 1.25rem;
      height: 1.25rem;
    }
    .nav-icon img {
      width: 1.25rem;
      height: 1.25rem;
      object-fit: contain;
    }
    
    /* 集团站群图标特殊样式（如有需要可调整） */
    .nav-menu-item .nav-icon img[alt="集团站群"] {
      width: 1.25rem;
      height: 1.25rem;
      object-fit: contain;
    }
     /* 集团站群二级菜单 */
     .nav-menu-jituan:hover .nav-submenu,
     .nav-menu-jituan:focus-within .nav-submenu {
       opacity: 1;
       pointer-events: auto;
       transform: translateY(0);
     }
    
    /* 二级菜单 */
    .nav-menu-item-haschild:hover .nav-submenu,
    .nav-menu-item-haschild:focus-within .nav-submenu {
      opacity: 1;
      pointer-events: auto;
      transform: translateY(0);
    }
    .nav-submenu {
      display: block;
      opacity: 0;
      pointer-events: none;
      position: absolute;
      left: 0;
      top: 70px;
      min-width: 11.25rem;
      background: rgba(255,255,255,0.3);
      box-shadow: 0 4px 16px rgba(0,0,0,0.12);
      border-radius: 0 0 8px 8px;
      z-index: 100;
      padding: 0.5rem 0;
      transform: translateY(20px);
      transition: opacity 0.3s cubic-bezier(.4,0,.2,1), transform 0.3s cubic-bezier(.4,0,.2,1);
    }
    .nav-submenu-item {
      display: flex;
      align-items: center;
    }
    .nav-submenu-item > a {
      display: flex;
      align-items: center;
      color: #222;
      font-size: 0.875rem;
      font-weight: normal;
      padding: 0.625rem 1.75rem 0.625rem 1.25rem;
      text-decoration: none;
      transition: background 0.2s, color 0.2s, font-weight 0.2s;
      width: 100%;
    }
    .nav-submenu-item > a:hover,
    .nav-submenu-item-active > a {
      background: #f5f5f5;
      color: #222;
      font-weight: bold;
      border-radius: 4px;
    }
    
    /* 右侧图标区域 */
    .nav-right-icons {
      display: flex;
      align-items: center;
      margin-left: auto;
      gap: 1.125rem;
    }
    .nav-right-icon {
      width: 1.5rem;
      height: 1.5rem;
      display: flex;
      align-items: center;
      justify-content: center;
      cursor: pointer;
      color: #fff;
      transition: color 0.2s;
      text-shadow: 0 1px 4px rgba(0,0,0,0.18);
    }
    .nav-right-icon:hover {
      color: #ffd700;
    }
    
    /* 集团站群下拉菜单靠右展开 */
    .nav-menu-jituan .nav-submenu {
      right: 0;
      left: auto;
      min-width: 20rem;
    }
   
    .nav-menu-jituan .nav-submenu-item > a {
      padding: 0.55rem 1.5rem 0.55rem 1.1rem;
      font-size: 0.85rem;
      color: #222;
      transition: background 0.2s, color 0.2s, font-weight 0.2s;
      font-weight: 400;
    }
    .nav-menu-jituan .nav-submenu-item > a:hover,
    .nav-menu-jituan .nav-submenu-item-active > a {
      background: #f0f6ff;
      color: #005bac;
      font-weight: bold;
      border-radius: 6px;
    }
    .nav-menu-jituan .nav-title {
      white-space: nowrap;
      overflow: hidden;
      text-overflow: ellipsis;
      max-width: 18rem;
    }
  
  /* 移动端汉堡菜单 */
  .mobile-menu-toggle {
      display: none;
      align-items: center;
      justify-content: center;
      width: 2.5rem;
      height: 2.5rem;
      cursor: pointer;
      margin-left: auto;
      margin-right: 1rem;
      z-index: 1112;
  }
  
  .mobile-menu-toggle img {
      width: 1.5rem;
      height: 1.5rem;
      filter: brightness(0) invert(1);
      transition: transform 0.3s ease;
  }
  
  .mobile-menu-toggle:hover img {
      transform: scale(1.1);
  }
  
  /* 移动端遮罩层 */
  .mobile-overlay {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(0, 0, 0, 0.5);
      z-index: 1110;
      opacity: 0;
      visibility: hidden;
      transition: opacity 0.3s ease, visibility 0.3s ease;
  }
  
  .mobile-overlay-active {
      opacity: 1;
      visibility: visible;
  }
  
  /* 移动端抽屉导航 */
  .mobile-drawer {
      position: fixed;
      top: 0;
      left: -100%;
      width: 80%;
      max-width: 20rem;
      height: 100%;
      background: #fff;
      z-index: 1111;
      transition: left 0.3s ease;
      box-shadow: 2px 0 10px rgba(0, 0, 0, 0.1);
      overflow-y: auto;
  }
  
  .mobile-drawer-open {
      left: 0;
  }
  
  /* 移动端抽屉头部 */
  .mobile-drawer-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 1rem;
      background: #1a237e;
      border-bottom: 1px solid #e0e0e0;
  }
  
  .mobile-logo {
      height: 2rem;
      width: auto;
      filter: brightness(0) invert(1);
  }
  
  .mobile-close-btn {
      background: none;
      border: none;
      color: #fff;
      font-size: 1.5rem;
      cursor: pointer;
      padding: 0.5rem;
      border-radius: 50%;
      transition: background 0.2s ease;
  }
  
  .mobile-close-btn:hover {
      background: rgba(255, 255, 255, 0.1);
  }
  
  /* 移动端导航菜单 */
  .mobile-nav-menu {
      padding: 1rem 0;
  }
  
  .mobile-nav-item {
      border-bottom: 1px solid #f0f0f0;
  }
  
  .mobile-nav-item:last-child {
      border-bottom: none;
  }
  
  .mobile-nav-link {
      display: flex;
      align-items: center;
      padding: 1rem;
      color: #333;
      text-decoration: none;
      transition: background 0.2s ease;
      position: relative;
  }
  
  .mobile-nav-link:hover,
  .mobile-nav-item-active .mobile-nav-link {
      background: #f5f7fa;
      color: #1a237e;
  }
  
  .mobile-nav-icon {
      display: flex;
      align-items: center;
      margin-right: 0.75rem;
      width: 1.25rem;
      height: 1.25rem;
  }
  
  .mobile-nav-icon img {
      width: 1.25rem;
      height: 1.25rem;
      object-fit: contain;
  }
  
  .mobile-nav-title {
      flex: 1;
      font-size: 0.9rem;
      font-weight: 500;
  }
  
  .mobile-nav-arrow {
      font-size: 0.75rem;
      color: #666;
      transition: transform 0.3s ease;
  }
  
  .mobile-nav-arrow-rotate {
      transform: rotate(180deg);
  }
  
  /* 移动端子菜单 */
  .mobile-nav-submenu {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: #f8f9fa;
  }
  
  .mobile-nav-submenu-open {
      max-height: 20rem;
  }
  
  .mobile-nav-submenu-item {
      display: block;
      padding: 0.75rem 1rem 0.75rem 2.5rem;
      color: #666;
      text-decoration: none;
      font-size: 0.85rem;
      border-bottom: 1px solid #e9ecef;
      transition: background 0.2s ease, color 0.2s ease;
  }
  
  .mobile-nav-submenu-item:hover,
  .mobile-nav-submenu-item-active {
      background: #e3f2fd;
      color: #1a237e;
  }
  
  .mobile-nav-submenu-item:last-child {
      border-bottom: none;
  }
  
  /* 响应式适配 */
  @media (max-width: 1000px) {
      .nav-header { 
          padding: 0 1rem; 
          width: 100%;
          box-sizing: border-box;
      }
      .nav-logo { 
          height: 2rem;
          margin-right: 1rem; 
      }
      .nav-logo img {
        height: 2rem;
        width: auto;
        filter: drop-shadow(0 1px 4px rgba(0,0,0,0.18));
      }
      .nav-menu-item {
        position: relative;
        margin: 0 0.8rem;
        display: flex;
        align-items: center;
        height: 4.375rem;
    }
      .nav-menu-item > a { 
          font-size: 0.75rem; 
      }
      
      /* 隐藏桌面端菜单 */
      .nav-menu {
          display: none;
      }
      
      /* 显示移动端汉堡菜单 */
      .mobile-menu-toggle {
          display: flex;
      }
      
      /* 调整右侧图标位置 */
      .nav-right-icons {
          position: static;
          margin-left: 0;
      }
      .nav-icon {
        display: inline-flex;
        align-items: center;
        margin-right: 1.5rem;
        width: 1.25rem;
        height: 1.25rem;
      }
  }
  
  @media (max-width: 600px) {
      .nav-header {
          padding: 0 0.75rem;
      }
      
      .mobile-drawer {
          width: 85%;
      }
      
      .mobile-nav-link {
          padding: 0.875rem 1rem;
      }
      
      .mobile-nav-title {
          font-size: 0.875rem;
      }
      
      .mobile-nav-submenu-item {
          padding: 0.625rem 1rem 0.625rem 2.25rem;
          font-size: 0.8rem;
      }
  }
  
  @media (max-width: 400px) {
      .mobile-drawer {
          width: 90%;
      }
      
      .mobile-nav-link {
          padding: 0.75rem 1rem;
      }
      
      .mobile-nav-title {
          font-size: 0.8rem;
      }
      
      .mobile-nav-submenu-item {
          padding: 0.5rem 1rem 0.5rem 2rem;
          font-size: 0.75rem;
      }
  }