* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: 'Microsoft YaHei', sans-serif;
        }
        header {
            width:100%; 
            background:rgba(0,0,0,0.1); 
            position: absolute; 
            top: 0; 
            z-index: 999;
        }

        .head {
            display: -webkit-box;
            display: -ms-flexbox;
            display: flex;
            -webkit-box-pack: justify;
                -ms-flex-pack: justify;
                    justify-content: space-between;
            -webkit-box-align: center;
                -ms-flex-align: center;
                    align-items: center;
            padding: 15px 20px;
            max-width: 1400px;
            margin: 0 auto;
        }

        .logo {
            height: 78px; 
            margin: 20px 0px 25px; 
            -webkit-box-flex: 0; 
                -ms-flex: 0 1 43%; 
                    flex:0 1 43%; 
            display: -webkit-box; 
            display: -ms-flexbox; 
            display: flex; 
            -webkit-box-align: center; 
                -ms-flex-align: center; 
                    align-items: center; 
        }
        .logo img { width: 100%; height:auto; }

        .search {
            display: -webkit-box;
            display: -ms-flexbox;
            display: flex;
            -webkit-box-align: center;
                -ms-flex-align: center;
                    align-items: center;
            width: 18.21%; 
            min-width: 200px; 
            height: 32px; 
            background: #f6f6f6; 
            border-radius: 10px; 
            position: relative; 
        }

        .search-input { height: 32px;}
        .search-title{ 
            width: 100%; 
            box-sizing: border-box; 
            height: 32px; 
            padding: 0px 15px; 
            line-height: 32px; 
            color: rgba(161, 161, 161, 0.6);
            font-size: 14px; 
            border: 0; 
            outline: 0;
            background: none;
            font-family: Microsoft YaHei;
        }
        .search-btn { width: 32px;height: 32px;position: absolute; right: 0; top: 0;}
        .search-submit { 
            position: relative; 
            width: 32px; 
            height: 32px; 
            border: 0;
            outline: 0;
            border-radius: 10px; 
            background: #1f98ba url(../images/search.png) no-repeat center; 
            background-size: 20px 20px; 
            cursor: pointer;
        }


        /* 导航样式 */
        nav { width: 100%; max-width:1400px; margin:0 auto; border-top:1px solid #fff; }

        .nav-links, .submenu {
            list-style: none;
        }

        .nav-links {
            display: -webkit-box;
            display: -ms-flexbox;
            display: flex;
            -webkit-box-pack: distribute;
                -ms-flex-pack: distribute;
                    justify-content: space-around;
            position: relative;
        }

        .nav-links > li {
            position: relative;
        }

        .nav-links li a {
            color: white;
            text-decoration: none;
            padding: 15px 20px;
            display: block;
            font-size: 22px;
            transition: background 0.3s;
            white-space: nowrap;
            position: relative;
        }

        .nav-links li a:hover {
            border-bottom: 3px solid #1991b2;
        }

        /* 下拉菜单样式 */
        .submenu {
            position: absolute;
            top: 100%;
            left: 50%;
            transform: translateX(-50%);
            background: rgba(25, 148, 178, 0.7);
            min-width: 130px;
            text-align:center;
            display: none;
            z-index: 100;
            box-shadow: 0 2px 5px #089eb833;
        }

        .submenu li {
            border-bottom: 1px solid #0675a8;
            position: relative;
        }

        .submenu li a {
            font-size:18px;
            border-bottom: 1px solid #0675a8;
            position: relative;
        }

        .submenu .submenu {
            top: 0;
            left: 100%;
            transform: translateX(0px);
        }

        /* 有子菜单的项添加箭头 */
        .nav-links li.has-submenu > a::after {
            content: "›";
            margin-left: 5px;
            display: inline-block;
            -webkit-transform: rotate(90deg);
                -ms-transform: rotate(90deg);
                    transform: rotate(90deg);
            position: absolute;
            right: 2px;
            font-size: 18px;
            line-height: 1;
           top:24px;
            
        }

        .submenu li.has-submenu > a::after {
            -webkit-transform: rotate(0deg);
                -ms-transform: rotate(0deg);
                    transform: rotate(0deg);
        }

        /* 鼠标悬停显示子菜单 */
        .nav-links li:hover > .submenu,
        .submenu li:hover > .submenu {
            display: block;
        }

        /* 汉堡菜单按钮 */
        .hamburger {
            display: none;
            cursor: pointer;
            padding: 10px;
            z-index: 1000;
        }

        .hamburger div {
            width:30px;
            height:4px;
            background:hsl(180, 100%, 100%);
            margin: 5px 0;
            transition: all 0.3s ease;
        }

        /* 响应式设计 */
        @media (max-width: 992px) {
            .submenu {
                min-width: 180px;
            }

            .logo {
                -webkit-box-flex: 0;
                    -ms-flex: 0 1 53%;
                        flex: 0 1 53%;
                display: -webkit-box;
                display: -ms-flexbox;
                display: flex;
                -webkit-box-align: center;
                    -ms-flex-align: center;
                        align-items: center;
            }
            nav {border-top:none;} 
            
            /* 移动端导航容器 */
            .nav-links {
                display: none;
                -webkit-box-orient: vertical;
                -webkit-box-direction: normal;
                    -ms-flex-direction: column;
                        flex-direction: column;
                width: 100%;
                position: absolute;
                top: 100%;
                left: 0;
                background: rgba(25, 148, 178, 0.7);
                z-index: 999;
                max-height: 0;
                overflow: hidden;
                transition: max-height 0.3s ease-out;
           
            }

            .nav-links.active {
                display: block; /* 关键修复：兼容模式下使用display:block替代flex */
                max-height: 1000px;
                transition: max-height 0.5s ease-in;
            }

            .nav-links > li {
                border-bottom: 1px solid #0675a8;
                position: relative;
            }

           .nav-links li a {
                padding: 12px 20px;
            }

            /* 移动端下拉菜单 */
            .submenu {
                position: static;
                display: none;
                background: rgba(0,0,0,0.1);
                box-shadow: none;
                padding-left: 20px;
                max-height: 0;
                overflow: hidden;
                transition: max-height 0.3s ease-out;
               transform: translateX(0px);
               text-align: left;
            }

            .submenu .submenu {
                padding-left: 20px;
            }

            .submenu.active {
                display: block;
                max-height: 1000px;
                transition: max-height 0.5s ease-in;
            }

            /* 移动端箭头样式 */
            .nav-links li.has-submenu > a::after {
                -webkit-transform: rotate(0deg);
                    -ms-transform: rotate(0deg);
                        transform: rotate(0deg);
                transition: -webkit-transform 0.3s;
                transition: transform 0.3s;
                transition: transform 0.3s, -webkit-transform 0.3s;
                right: 20px;
            }

            .nav-links li.has-submenu > a.active::after {
                -webkit-transform: rotate(90deg);
                    -ms-transform: rotate(90deg);
                        transform: rotate(90deg);
            }

            .hamburger {
                display: block;
                order: 1;
            }

            .logo {
                order: 2;
                margin: 0 auto;
            }

            .search {
                order: 3;
            }

            /* 汉堡菜单动画 */
            .hamburger.active div:nth-child(1) {
                -webkit-transform: rotate(-45deg) translate(-5px, 6px);
                    -ms-transform: rotate(-45deg) translate(-5px, 6px);
                        transform: rotate(-45deg) translate(-5px, 6px);
            }

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

            .hamburger.active div:nth-child(3) {
                -webkit-transform: rotate(45deg) translate(-5px, -6px);
                    -ms-transform: rotate(45deg) translate(-5px, -6px);
                        transform: rotate(45deg) translate(-5px, -6px);
            }
        }
        
        @media (max-width: 768px) {
            .head {
                padding: 10px;
                -webkit-box-orient: horizontal;
                -webkit-box-direction: normal;
                    -ms-flex-flow: row wrap;
                        flex-flow: row wrap;
            }

            .logo { width: 80%; -webkit-box-flex: 0; -ms-flex: 0 1 80%; flex: 0 1 80%; }

            .search { 
                width: 90%; 
                display:-webkit-box; 
                display:-ms-flexbox; 
                display:flex; 
                -webkit-box-flex: 1; 
                    -ms-flex:1 1 100%; 
                        flex:1 1 100%; 
                margin: 4% auto; 
                position: relative; 
            }
        }