* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: "Microsoft YaHei", sans-serif;
        }

        :root {
            --primary: #409eff;
            --primary-dark: #337ecc;
            --dark: #1f2937;
            --light: #f9fafb;
            --gray: #6b7280;
        }

        html {
            scroll-behavior: smooth;
        }

        body {
            line-height: 1.6;
        }

        section {
            padding: 80px 20px;
            max-width: 1400px;
            margin: 0 auto;
        }

        .btn {
            display: inline-block;
            padding: 14px 32px;
            background: var(--primary);
            color: white;
            border-radius: 50px;
            text-decoration: none;
            font-size: 16px;
            font-weight: bold;
            transition: all 0.3s ease;
            border: none;
            cursor: pointer;
        }

        .btn:hover {
            background: var(--primary-dark);
            transform: translateY(-3px);
            box-shadow: 0 10px 20px rgba(40, 39, 34, 0.3);
        }

        .section-title {
            text-align: center;
            font-size: 36px;
            color: var(--dark);
            margin-bottom: 60px;
            position: relative;
        }

        .section-title::after {
            content: "";
            width: 80px;
            height: 4px;
            background: var(--primary);
            position: absolute;
            bottom: -15px;
            left: 50%;
            transform: translateX(-50%);
            border-radius: 2px;
        }

        /* 导航栏 */
        nav {
            position: fixed;
            top: 0;
            width: 100%;
            background: rgba(255, 255, 255, 0.95);
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
            z-index: 999;
            padding: 15px 0;
            transition: padding 240ms ease, box-shadow 240ms ease, background-color 240ms ease, transform 240ms ease;
        }

        nav.nav--scrolled {
            padding: 10px 0;
            background: rgba(255,255,255,0.98);
            box-shadow: 0 8px 28px rgba(0,0,0,0.12);
        }

        .nav-container {
            max-width: 1400px;
            margin: 0 auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 0 20px;
        }

        .logo {
            font-size: 24px;
            font-weight: bold;
            color: var(--primary);
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .nav-menu {
            display: flex;
            align-items: center;
            list-style: none;
            gap: 32px;
        }

        .nav-menu a {
            text-decoration: none;
            color: var(--dark);
            font-size: 16px;
            font-weight: 500;
            transition: color 0.3s;
        }

        .nav-menu a:hover {
            color: var(--primary);
        }

        /* Banner */
        .banner {
            height: 100vh;
            background-image: url(https://picsum.photos/id/1057/1920/1080);
            background-size: cover;
            background-position: center;
            background-attachment: fixed;
            display: flex;
            align-items: center;
            position: relative;
            padding: 0 20px;
        }

        .banner::before {
            content: "";
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.6);
            z-index: 1;
        }

        .banner-container {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 48px;
            width: 100%;
            max-width: 1400px;
            margin: 0 auto;
            position: relative;
            z-index: 2;
            text-align: left;
        }

        .banner-text {
            flex: 1;
            min-width: 320px;
        }

        .banner-text h1 {
            font-size: 60px;
            color: #fff;
            margin-bottom: 25px;
        }

        .banner-text p {
            font-size: 20px;
            color: rgba(255,255,255,0.92);
            max-width: 680px;
            margin: 0 0 40px;
        }

        .banner-img {
            flex: 1;
            min-width: 320px;
            display: flex;
            justify-content: flex-end;
        }

        .banner-img img {
            width: 100%;
            max-width: 620px;
            border-radius: 14px;
            box-shadow: 0 12px 32px rgba(0, 0, 0, 0.28);
            display: block;
        }

        /* 产品介绍 */
        .intro { background: #fff; }
        .intro-row {
            display: flex;
            align-items: center;
            gap: 60px;
            flex-wrap: wrap;
        }
        .intro-img {
            flex: 1;
            min-width: 300px;
            border-radius: 16px;
            overflow: hidden;
            box-shadow: 0 8px 24px rgba(0,0,0,0.1);
        }
        .intro-img img { width: 100%; display: block; }
        .intro-text { flex:1; min-width:300px; }
        .intro-text h3 { font-size:30px; margin-bottom:20px; }
        .intro-text p { font-size:16px; color:var(--gray); line-height:1.8; margin-bottom:12px; }

        /* 核心功能 */
        .features { background: var(--light); }
        .features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 28px;
        }
        .feature-card {
            background: #fff;
            padding: 35px 25px;
            border-radius:15px;
            text-align:center;
            transition:0.3s;
            box-shadow:0 3px 12px rgba(0,0,0,0.05);
        }
        .feature-card:hover { transform:translateY(-8px); }
        .feature-card i { font-size:46px; color:var(--primary); margin-bottom:18px; }
        .feature-card h4 { font-size:19px; margin-bottom:12px; }
        .feature-card p { color:var(--gray); font-size:15px; }

        /* 使用场景 */
        .scene { background:#fff; }
        .scene-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
            gap: 28px;
        }
        .scene-item {
            border-radius:16px;
            overflow:hidden;
            box-shadow:0 4px 12px rgba(0,0,0,0.06);
            transition:0.3s;
        }
        .scene-item:hover { transform:translateY(-6px); }
        .scene-img { height:180px; }
        .scene-img img { width:100%; height:100%; object-fit:cover; }
        .scene-info { padding:22px; }
        .scene-info h4 { font-size:18px; margin-bottom:8px; }
        .scene-info p { color:var(--gray); font-size:15px; }

        /* 售后 */
        .service { background:var(--light); }
        .service-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
            gap:25px;
        }
        .service-item {
            background:#fff;
            padding:28px;
            border-radius:12px;
            text-align:center;
        }
        .service-item i { font-size:36px; color:var(--primary); margin-bottom:15px; }
        .service-item h4 { font-size:18px; margin-bottom:10px; }
        .service-item p { color:var(--gray); }

        /* 下载 */
        .download {
            background: linear-gradient(135deg, #409eff 0%, #337ecc 100%);
            color:white;
            text-align:center;
            padding:100px 20px;
        }
        .download h2 { font-size:40px; margin-bottom:20px; }
        .download p { max-width:700px; margin:0 auto 35px; font-size:18px; }
        .download .btn { background:#fff; color:var(--primary); font-size:18px; }

        footer {
            background:var(--dark);
            color:white;
            text-align:center;
            padding:40px 20px;
        }
        footer p { color:#9ca3af; }

        @media (max-width:768px){
            .nav-menu{display:none;}
            .banner{
                background-attachment: scroll;
            }
            .banner-container{
                flex-direction: column;
                gap: 24px;
                align-items: flex-start;
            }
            .banner-text h1{font-size:36px;}
            .banner-text p{
                font-size:16px;
                margin-bottom:28px;
                max-width:100%;
            }
            .banner-img{
                width:100%;
                min-width:0;
                justify-content:flex-start;
            }
            .banner-img img{
                max-width:100%;
            }
        }

        /* 教程列表 */
         /* 顶部小banner */
        .page-banner {
            height: 420px;
            background-image: url(https://picsum.photos/id/1076/1920/1080);
            background-size: cover;
            background-position: center;
            background-attachment: fixed;
            position: relative;
            display: flex;
            align-items: center;
            justify-content: center;
            text-align: center;
            color: white;
            margin-top: 80px;
        }

        .page-banner::before {
            content: '';
            position: absolute;
            left: 0; top: 0; width: 100%; height: 100%;
            background: rgba(0,0,0,0.55);
        }

        .page-banner .inner {
            position: relative; z-index: 2;
        }

        .page-banner h1 {
            font-size: 46px;
            margin-bottom: 15px;
        }

        .page-banner p {
            font-size: 18px;
            max-width: 700px;
            margin: 0 auto;
            opacity: 0.95;
        }
        .video-page{max-width:1400px;margin:0 auto;padding:80px 20px;}
        .video-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(310px,1fr));gap:30px;}
        .video-card{background:#fff;border-radius:16px;overflow:hidden;box-shadow:0 4px 12px rgba(0,0,0,0.06);transition:0.3s;}
        .video-card:hover{transform:translateY(-6px);}
        .video-cover{position:relative;width:100%;height:200px;}
        .video-cover img{width:100%;height:100%;object-fit:cover;}
        .video-play{position:absolute;top:50%;left:50%;transform:translate(-50%,-50%);width:60px;height:60px;background:rgba(64,158,255,0.8);border-radius:50%;display:flex;align-items:center;justify-content:center;color:white;font-size:22px;}
        .video-info{padding:22px;}
        .video-title{font-size:17px;font-weight:500;margin-bottom:8px;}
        .video-desc{font-size:14px;color:var(--gray);}

        @media (max-width:768px) {
            .page-banner h1 { font-size: 32px; }
            .page-banner { height: 320px; }
            .video-grid { grid-template-columns: 1fr; }
        }