/* 基础样式重置 */
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    /* 导航主容器 */
    .ip-navigation {
      background: linear-gradient(135deg, #1a3a8f 0%, #0d47a1 100%);
      position: relative;
      z-index: 1000;
      font-family: 'Microsoft YaHei', sans-serif;
    }
    
    .ip-container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 15px;
      height: 60px;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    
    /* 品牌标识 */
    .ip-brand {
      display: flex;
      align-items: center;
      z-index: 1001;
    }
    
    .ip-brand a {
      color: white;
      text-decoration: none;
      font-weight: bold;
      font-size: 18px;
    }
    
    /* 桌面端导航菜单 */
    .ip-menu {
      display: flex;
      list-style: none;
    }
    
    .ip-item {
      position: relative;
    }
    
    .ip-link {
      color: rgba(255,255,255,0.9);
      text-decoration: none;
      padding: 0 18px;
      height: 60px;
      display: flex;
      align-items: center;
      font-size: 15px;
      transition: all 0.3s;
    }
    
    .ip-link:hover {
      color: white;
      background: rgba(255,255,255,0.1);
    }
    
    /* 高亮菜单项 */
    .ip-highlight {
      background: #ff9100;
      border-radius: 4px;
      margin-left: 10px;
    }
    
    .ip-highlight:hover {
      background: #ff6d00;
    }
    
    /* 下拉菜单 */
    .ip-submenu {
      position: absolute;
      top: 100%;
      left: 0;
      background: white;
      min-width: 200px;
      box-shadow: 0 5px 20px rgba(0,0,0,0.1);
      border-radius: 0 0 4px 4px;
      opacity: 0;
      visibility: hidden;
      transform: translateY(10px);
      transition: all 0.3s;
      z-index: 100;
    }
    
    .ip-dropdown:hover .ip-submenu {
      opacity: 1;
      visibility: visible;
      transform: translateY(0);
    }
    
    .ip-sublink {
      display: block;
      padding: 12px 20px;
      color: #333;
      border-bottom: 1px solid #f0f0f0;
      transition: all 0.2s;
    }
    
    .ip-sublink:hover {
      background: #f5f9ff;
      color: #1a3a8f;
    }
    
    /* 移动端按钮 - 完全可见 */
    .ip-mobile-btn {
      display: none;
      width: 44px;
      height: 44px;
      background: rgba(255,255,255,0.2);
      border: none;
      border-radius: 4px;
      position: relative;
      cursor: pointer;
      z-index: 1001;
    }
    
    .ip-mobile-btn span {
      display: block;
      width: 22px;
      height: 2px;
      background: white;
      position: absolute;
      left: 11px;
      transition: all 0.3s;
    }
    
    .ip-mobile-btn span:nth-child(1) { top: 15px; }
    .ip-mobile-btn span:nth-child(2) { top: 21px; }
    .ip-mobile-btn span:nth-child(3) { top: 27px; }
    
    /* 移动端菜单激活状态 */
    .ip-mobile-btn.active {
      background: rgba(255,255,255,0.3);
    }
    
    .ip-mobile-btn.active span:nth-child(1) {
      transform: rotate(45deg);
      top: 21px;
    }
    
    .ip-mobile-btn.active span:nth-child(2) {
      opacity: 0;
    }
    
    .ip-mobile-btn.active span:nth-child(3) {
      transform: rotate(-45deg);
      top: 21px;
    }
    
    /* 移动端样式 (小于992px) */
    @media (max-width: 992px) {
      .ip-mobile-btn {
        display: block;
      }
      
      .ip-menu {
        position: fixed;
        top: 60px;
        left: 0;
        width: 100%;
        background: #0d47a1;
        flex-direction: column;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.4s ease-out;
        box-shadow: 0 10px 15px rgba(0,0,0,0.1);
      }
      
      .ip-menu.active {
        max-height: calc(100vh - 60px);
        overflow-y: auto;
      }
      
      .ip-item {
        border-bottom: 1px solid rgba(255,255,255,0.1);
      }
      
      .ip-link {
        padding: 15px 20px;
        height: auto;
        justify-content: space-between;
      }
      
      .ip-highlight {
        margin: 15px;
        text-align: center;
      }
      
      /* 移动端下拉菜单 */
      .ip-submenu {
        position: static !important;
        box-shadow: none !important;
        background: rgba(0,0,0,0.15) !important;
        opacity: 1 !important;
        visibility: visible !important;
        transform: none !important;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.3s ease-out;
      }
      
      .ip-dropdown.active .ip-submenu {
        max-height: 500px;
      }
      
      .ip-sublink {
        padding-left: 35px !important;
        color: white !important;
        border-color: rgba(255,255,255,0.1) !important;
      }
      
      .ip-sublink:hover {
        background: rgba(255,255,255,0.1) !important;
      }
      
      /* 下拉箭头指示器 */
      .ip-dropdown .ip-link::after {
        content: '+';
        font-size: 18px;
        transition: transform 0.3s;
      }
      
      .ip-dropdown.active .ip-link::after {
        content: '-';
      }
    }