/* 1. 样式重置与全局变量 */
        :root { 
            --main-blue: #165DFF; 
            --accent-orange: #e8f3ff; 
            --bg-light: #f8f9fa; 
            --text-dark: #333;
            --text-gray: #666; 
        }
        * { box-sizing: border-box; margin: 0; padding: 0; }
        html { scroll-behavior: smooth; }
        body { font-family: "PingFang SC", "Microsoft YaHei", sans-serif; color: var(--text-dark); line-height: 1.8; }
        a {text-decoration: none;transition: 0.3s;color: inherit;}
        /* 容器自适应关键 */
        .container { width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 15px; }
        img { max-width: 100%; height: auto; display: block; }
        .case-img {  height: 229px;  }

        /* 通用标题 */
        .sec-header { text-align: center; margin: 60px 0 40px; }
        .sec-header h2 { font-size: 32px; color: #165DFF; margin-bottom: 10px; position: relative; }
        .sec-header p { color: #888; font-size: 16px; }
        .sec-header h2::after { content: ''; width: 60px; height: 3px; background: var(--accent-orange); display: block; margin: 15px auto; }

        /* 2. 头部与导航 */
        header { background: #fff; padding: 15px 0; }
        .header-flex { display: flex; justify-content: space-between; align-items: center; }
        .phone { font-size: 20px; color: var(--main-blue); font-weight: bold; }

        .main-nav { background: #fff; border-top: 1px solid #eee; position: sticky; top: 0; z-index: 1000; box-shadow: 0 2px 5px rgba(0,0,0,0.05); }
        .nav-list { display: flex; justify-content: space-between; list-style: none; }
        .nav-list > li { position: relative; }
        .nav-list > li > a { display: block; padding: 15px 10px; color: #333; font-size: 16px; text-decoration: none; transition: 0.3s; }
        .nav-list > li > a:hover, .nav-list > li > a.active { color: #165DFF; }

        /* 下拉菜单 */
        .dropdown:hover .submenu { display: block; animation: fadeIn 0.3s; }
        .submenu { 
            display: none; position: absolute; top: 100%; left: 0; background: #fff; 
            min-width: 160px; box-shadow: 0 5px 15px rgba(0,0,0,0.1); border-top: 2px solid #165DFF; list-style: none; 
        }
        .submenu li a { display: block; padding: 10px 20px; color: #666; font-size: 14px; text-decoration: none; }
        .submenu li a:hover { background: #e8f3ff; color: #165DFF; }

        /* 3. Banner */
        .banner { 
            background: linear-gradient(rgba(0,0,0,0.5), rgba(0,0,0,0.5)), url('../images/casebg.png') no-repeat center/cover;
            height: 450px; color: #fff; display: flex; align-items: center; 
        }
        .banner h1 { font-size: 42px; margin-bottom: 10px; }
        .banner p { font-size: 22px; margin-bottom: 30px; }
        .btn-quote { background: #165DFF; color: #fff; padding: 15px 40px; text-decoration: none; border-radius: 5px; font-weight: bold; font-size: 18px; }

        /* 4. 网格布局系统 */
        .grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
        .feature-card { border: 1px solid #eee; padding: 30px; text-align: center; transition: 0.3s; }
        .feature-card:hover { box-shadow: 0 10px 20px rgba(0,0,0,0.1); transform: translateY(-5px); }
        .feature-card h3 { color: var(--main-blue); margin-bottom: 10px; }

        /* 解决方案项 */
        .solution-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
        .solution-item { position: relative; overflow: hidden; border-radius: 8px; }
        .solution-item img { transition: 0.5s; width: 100%; }
        .solution-item:hover img { transform: scale(1.1); }
        .solution-info { position: absolute; bottom: 0; left: 0; right: 0; background: rgba(0,0,0,0.6); color: #fff; padding: 15px; text-align: center; }

        /* 视频展示 */
        .video-box { background: #000; border-radius: 12px; overflow: hidden; box-shadow: 0 20px 40px rgba(0,0,0,0.2); }
        video { width: 100%; height: auto; display: block; }
        #mse { width: 100%; height: 100%!important; display: block; }

        /* 精工细节 */
        .details-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; margin-top: 40px; }
        .detail-item { border: 1px solid #f0f0f0; transition: 0.3s; position: relative; overflow: hidden; background: #fff; }
        .detail-item:hover { border-color: var(--main-blue); box-shadow: 0 10px 30px rgba(0,0,0,0.08); }
        .detail-img { height: 240px; overflow: hidden; }
        .detail-img img { width: 100%; height: 100%; object-fit: cover; }
        .detail-content { padding: 25px; }
        .detail-content h3 { font-size: 20px; display: flex; align-items: center; margin-bottom: 12px; }
        .detail-content h3::before { content: ""; width: 4px; height: 18px; background: var(--accent-orange); margin-right: 10px; border-radius: 2px; }
        .detail-tag { position: absolute; top: 15px; left: 15px; background: #165DFF; color: #fff; padding: 4px 12px; font-size: 12px; border-radius: 20px; z-index: 1; }

        /* 案例墙 */
        .case-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 15px; }
        .case-item { background: #fff; border: 1px solid #eee; padding: 10px; border-radius: 4px; text-align: center; }
        .case-item span { font-size: 14px; font-weight: bold; display: block; margin-top: 10px; }

        /* 5. 表单 */
        .form-wrap { background: linear-gradient(135deg, #004a99 0%, #002d5e 100%); padding: 60px 0; color: #fff; }
        .form-flex { display: flex; align-items: center; justify-content: space-between; gap: 30px; }
        .main-form { background: #fff; padding: 30px; border-radius: 8px; width: 450px; color: #333; }
        .main-form input, .main-form select { width: 100%; padding: 12px; margin-bottom: 15px; border: 1px solid #ddd; border-radius: 4px; }
        .submit-btn { background: var(--accent-orange); color: #000; border: none; width: 100%; padding: 15px; font-size: 18px; font-weight: bold; cursor: pointer; border-radius: 4px; }

        /* 6. 返回顶部 */
        .back-to-top {
            position: fixed; right: 2px; bottom: 50px; width: 50px; height: 50px;
            background-color: #165DFF; color: white; border-radius: 4px;
            display: flex; flex-direction: column; align-items: center; justify-content: center;
            cursor: pointer; z-index: 9999; opacity: 0; visibility: hidden; transition: 0.3s; box-shadow: 0 4px 12px rgba(0,0,0,0.15);
        }
        .back-to-top.show { opacity: 1; visibility: visible; }
        .back-to-top .arrow { width: 0; height: 0; border-left: 8px solid transparent; border-right: 8px solid transparent; border-bottom: 10px solid white; margin-bottom: 4px; }

        /* 7. 响应式补丁 (重点) */
        @media (max-width: 992px) {
            .grid, .solution-grid, .details-grid { grid-template-columns: 1fr 1fr; }
            .case-grid { grid-template-columns: repeat(2, 1fr); }
            .form-flex { flex-direction: column; text-align: center; }
            .main-form { width: 100%; }
            .case-img {  height: 229px;  }
        }
        @media (max-width: 768px) {
            .nav-list { overflow-x: auto; white-space: nowrap; justify-content: flex-start; }
            .nav-list > li > a { padding: 15px 15px; font-size: 14px; }
            .banner h1 { font-size: 28px; }
            .banner p { font-size: 18px; }
            .grid, .solution-grid, .details-grid, .case-grid { grid-template-columns: 1fr; }
            .header-flex { flex-direction: column; gap: 10px; text-align: center; }
            .back-to-top { right: 15px; bottom: 20px; width: 40px; height: 40px; }
            .case-img { height: auto;  }
        }

        @keyframes fadeIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }
		
		 /* 2. 视频展示区 */
        .video-box { background: #000; border-radius: 12px; overflow: hidden; position: relative; box-shadow: 0 20px 40px rgba(0,0,0,0.2); }
        .video-placeholder { width: 100%; height: 500px; display: flex; align-items: center; justify-content: center; background: #333; color: #fff; flex-direction: column; }
        .play-icon { font-size: 60px; margin-bottom: 20px; color: var(--accent-orange); cursor: pointer; }