/* 主导航容器 */
        .main-nav {
            /*background-color: #2c3e50;*/
            /*box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);*/
            position: relative;
            z-index: 9999;
        }

        /* 导航列表 */
        .nav-list {
            display: flex;
            justify-content: center;
            list-style: none;
            max-width: 1200px;
            margin: 0 auto;
        }

        /* 导航菜单项 */
        .nav-item {
            position: relative;
            perspective: 1000px; /* 3D透视效果 */
            transform-style: preserve-3d;
        }

        /* 导航链接 */
        .nav-item > a {
            display: block;
            color: #000;
            text-decoration: none;
            padding: 10x 10px;
                font-size:1rem;
            transition: all 0.3s ease;
            transform-style: preserve-3d;
            transform: translateZ(10px);
        }

        /* 导航项hover样式 */
        .nav-item:hover > a {
            background-color: #fff;
            color: #008040;
            transform: translateY(-2px) translateZ(10px);
        }

        /* 下拉菜单容器 */
        .dropdown {
            position: absolute;
            top: 100%;
            padding:0;
            left: 0;
            list-style: none;
            width: 220px;
            background-color: white;
            border-radius: 4px;
            box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
            overflow: hidden;
            transform-style: preserve-3d;
            transform-origin: top center;
            /* 初始3D折叠状态 */
            transform: rotateX(-90deg);
            opacity: 0;
            visibility: hidden;
            transition: 
                transform 0.4s cubic-bezier(0.68, -0.55, 0.27, 1.55),
                opacity 0.3s ease,
                visibility 0.3s ease;
            z-index: 999;
            max-height: 800px;
            overflow-y: auto; /* 处理下拉项过多的滚动 */
        }

        /* 鼠标滑过显示下拉菜单 */
        .nav-item:hover .dropdown {
            transform: rotateX(0deg);
            opacity: 1;
            visibility: visible;
        }

        /* 下拉菜单项 */
        .dropdown li {
            border-bottom: 1px solid #f1f1f1;
            transform-style: preserve-3d;
            transition: all 0.2s ease;
        }

        .dropdown li:last-child {
            border-bottom: none;
        }

        /* 下拉菜单链接 */
        .dropdown li a {
            display: block;
            padding: 12px 16px;
            color: #2c3e50;
            font-size:1rem;
            text-decoration: none;
            transition: all 0.2s ease;
            transform: translateZ(5px);
        }

        /* 下拉菜单项hover */
        .dropdown li:hover {
            background-color: #f8f9fa;
            transform: translateZ(8px);
        }

        .dropdown li a:hover {
            color: #008040;
            padding-left: 20px;
        }

        /* 滚动条样式优化（下拉菜单） */
        .dropdown::-webkit-scrollbar {
            width: 6px;
        }

        .dropdown::-webkit-scrollbar-track {
            background: #f1f1f1;
        }

        .dropdown::-webkit-scrollbar-thumb {
            background: #ccc;
            border-radius: 3px;
        }

        .dropdown::-webkit-scrollbar-thumb:hover {
            background: #bbb;
        }

        /* 响应式适配 */
        @media (max-width: 768px) {
            .nav-list {
                flex-wrap: wrap;
            }

            .nav-item {
                flex: 1 1 auto;
                text-align: left;
            }

            .nav-item > a {
                padding: 5px 16px;
                font-size: 14px;
            }

            .dropdown {
                width: 100%;
                left: 0;
            }
        }