* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        :root {
            --primary: #8b5cf6;
            --primary-dark: #7c3aed;
            --secondary: #f59e0b;
            --dark-bg: #0a0a0f;
            --dark-card: #12121a;
            --dark-surface: #1e1e2a;
            --text-primary: #ffffff;
            --text-secondary: #b3b3c4;
            --gradient-primary: linear-gradient(135deg, #8b5cf6 0%, #c084fc 100%);
            --gradient-accent: linear-gradient(135deg, #f59e0b 0%, #ef4444 100%);
            --border-subtle: rgba(255, 255, 255, 0.08);
        }

        body {
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft YaHei', sans-serif;
            background-color: var(--dark-bg);
            color: var(--text-primary);
            line-height: 1.5;
            overflow-x: hidden;
        }

        .container {
            max-width: 1280px;
            margin: 0 auto;
            padding: 0 24px;
        }

        /* 导航栏 */
        .header {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            background: rgba(10, 10, 15, 0.85);
            backdrop-filter: blur(14px);
            z-index: 1000;
            border-bottom: 1px solid var(--border-subtle);
        }

        .nav-container {
            max-width: 1280px;
            margin: 0 auto;
            padding: 16px 24px;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .logo {
            display: flex;
            align-items: center;
            gap: 12px;
            font-size: 26px;
            font-weight: 800;
            background: #fff;
            -webkit-background-clip: text;
            background-clip: text;
            -webkit-text-fill-color: transparent;
        }
        .logo-icon {
            width: 38px;
            height: 38px;
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 800;
            font-size: 22px;
            color: white;
            -webkit-text-fill-color: white;
        }
        .logo-icon img {
            width: 30px;
            height: auto;
        }
        .nav-menu {
            display: flex;
            list-style: none;
            gap: 36px;
        }
        .nav-menu a {
            color: var(--text-secondary);
            text-decoration: none;
            font-weight: 500;
            transition: color 0.2s;
            font-size: 1rem;
        }
        .nav-menu a:hover {
            color: var(--text-primary);
        }
        /* hero */
        .hero {
            margin-top: 80px;
            padding: 100px 20px 80px;
            text-align: center;
            position: relative;
            overflow: hidden;
            background: radial-gradient(ellipse 80% 50% at 50% 30%, rgba(139,92,246,0.2), transparent);
        }
        .hero h1 {
            font-size: 42px;
            font-weight: 800;
            color: #fff;
            margin-bottom: 24px;
            letter-spacing: -0.02em;
        }
        .hero-subtitle {
            font-size: 20px;
            color: var(--text-secondary);
            max-width: 720px;
            margin: 0 auto 36px;
        }
        .btn-group {
            display: flex;
            gap: 18px;
            justify-content: center;
            flex-wrap: wrap;
        }
        .btn-primary {
            background: var(--gradient-primary);
            padding: 14px 42px;
            border-radius: 60px;
            font-weight: 600;
            font-size: 18px;
            color: white;
            text-decoration: none;
            transition: transform 0.2s, box-shadow 0.2s;
            display: inline-block;
            box-shadow: 0 8px 20px rgba(139,92,246,0.3);
        }
        .btn-secondary {
            background: rgba(255,255,255,0.08);
            backdrop-filter: blur(4px);
            padding: 14px 38px;
            border-radius: 60px;
            font-weight: 600;
            font-size: 18px;
            color: var(--text-primary);
            text-decoration: none;
            border: 1px solid var(--border-subtle);
            transition: all 0.2s;
        }
        .btn-primary:hover, .btn-secondary:hover {
            transform: translateY(-3px);
        }
        .btn-primary:hover {
            box-shadow: 0 14px 28px rgba(139,92,246,0.4);
        }
        /* 通用section */
        section {
            padding: 90px 0;
        }
        .section-title {
            font-size: 42px;
            font-weight: 700;
            text-align: center;
            background: var(--gradient-primary);
            -webkit-background-clip: text;
            background-clip: text;
            -webkit-text-fill-color: transparent;
            margin-bottom: 18px;
        }
        .section-sub {
            text-align: center;
            color: var(--text-secondary);
            max-width: 700px;
            margin: 0 auto 56px;
            font-size: 18px;
        }
        .bg-dark-surface {
            background: var(--dark-surface);
        }
        /* 功能网格 */
        .grid-3 {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 32px;
        }
        .feature-card {
            background: var(--dark-card);
            padding: 36px 28px;
            border-radius: 28px;
            border: 1px solid var(--border-subtle);
            transition: all 0.25s;
        }
        .feature-card:hover {
            border-color: var(--primary);
            transform: translateY(-6px);
            box-shadow: 0 20px 32px -12px rgba(139,92,246,0.2);
        }
        .feature-card h3 {
            font-size: 24px;
            margin: 20px 0 12px;
        }
        .feature-card p {
            color: var(--text-secondary);
        }
        .feature-icon {
            font-size: 42px;
        }
        /* 案例 / 场景卡片 */
        .case-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 28px;
        }
        .case-item {
            background: var(--dark-card);
            border-radius: 24px;
            padding: 28px;
            border: 1px solid var(--border-subtle);
            transition: 0.2s;
        }
        .case-item:hover {
            border-color: var(--primary);
        }
        /* 视频教程网格 */
        .video-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
            gap: 28px;
        }
        .video-card {
            background: var(--dark-card);
            border-radius: 24px;
            overflow: hidden;
            border: 1px solid var(--border-subtle);
            transition: transform 0.2s, box-shadow 0.2s;
        }
        .video-card:hover {
            transform: translateY(-6px);
            border-color: var(--primary);
            box-shadow: 0 12px 28px rgba(139,92,246,0.2);
        }
        .video-wrapper {
            position: relative;
            width: 100%;
            padding-top: 56.25%; /* 16:9 */
            background: #000;
        }
        .video-wrapper iframe {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            border: none;
        }
        .video-info {
            padding: 20px;
        }
        .video-info h4 {
            font-size: 18px;
            margin-bottom: 8px;
        }
        .video-info p {
            color: var(--text-secondary);
            font-size: 14px;
        }
        .step-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: 30px;
        }
        .step-card {
            background: var(--dark-card);
            padding: 32px 24px;
            border-radius: 28px;
            border: 1px solid var(--border-subtle);
        }
        .step-number {
            width: 48px;
            height: 48px;
            background: var(--gradient-primary);
            border-radius: 30px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 800;
            font-size: 24px;
            margin-bottom: 24px;
        }
        .advantage-list {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(270px, 1fr));
            gap: 30px;
        }
        .advantage-block {
            background: var(--dark-card);
            padding: 28px;
            border-radius: 24px;
            border-left: 5px solid var(--primary);
        }
        .faq-item {
            background: var(--dark-card);
            padding: 28px 32px;
            border-radius: 24px;
            margin-bottom: 20px;
            border: 1px solid var(--border-subtle);
        }
        .footer {
            background: var(--dark-surface);
            text-align: center;
            padding: 48px 24px;
            border-top: 1px solid var(--border-subtle);
            color: var(--text-secondary);
        }
        @media (max-width: 768px) {
            .hero h1 { font-size: 38px; }
            .section-title { font-size: 32px; }
            .nav-menu { gap: 20px; }
            .btn-primary, .btn-secondary { padding: 12px 28px; font-size: 16px; }
            section { padding: 60px 0; }
        }
        @media (max-width: 600px) {
            .nav-container { flex-direction: column; gap: 12px; }
            .hero { margin-top: 110px; }
        }
        .badge {
            background: rgba(139,92,246,0.2);
            color: #c084fc;
            padding: 4px 12px;
            border-radius: 40px;
            font-size: 14px;
            font-weight: 500;
            display: inline-block;
            margin-bottom: 16px;
        }