/* 移动端菜单按钮样式 */
      .mobile-menu-button {
        display: none;
        position: fixed;
        top: 20px;
        left: 20px;
        width: 40px;
        height: 40px;
        background-color: #007bff;
        border-radius: 50%;
        justify-content: center;
        align-items: center;
        cursor: pointer;
        z-index: 1001;
        transition: transform 0.3s ease;
      }
      
      .mobile-menu-button i {
        color: white;
        font-size: 20px;
      }

      /* 移动端样式 - 小于768px */
      @media (max-width: 768px) {
        .header-content {
          padding: 15px;
          flex-direction: column;
          align-items: flex-start;
          background-color: transparent;
          transition: background-color 0.3s ease;
        }
        
        .logo-container {
          margin-left: 60px;
        }
        
        nav {
          display: none;
          width: 100%;
          margin-top: 20px;
        }
        
        nav ul {
          flex-direction: column;
          gap: 15px;
        }
        
        nav ul li a {
          color: white;
          display: block;
          padding: 10px 0;
          border-bottom: 1px solid rgba(255, 255, 255, 0.1);
        }
        
        .mobile-menu-button {
          display: flex;
        }
        
        /* 菜单展开时的样式 */
        .menu-open header {
          background-color: black;
        }
        
        .menu-open nav {
          display: block;
        }
        
        .menu-open .mobile-menu-button {
          transform: rotate(180deg);
        }
      }