:root {
            --bg-night: #0d0d12;
            --bg-night-2: #14141c;
            --bg-card: #1a1a24;
            --bg-elevated: #20202c;
            --ember: #8b5cf6;
            --ember-dark: #7c3aed;
            --ember-light: rgba(139, 92, 246, 0.12);
            --gold: #a78bfa;
            --gold-soft: rgba(167, 139, 250, 0.15);
            --text-primary: #f5f5f7;
            --text-secondary: rgba(245, 245, 247, 0.65);
            --text-muted: rgba(245, 245, 247, 0.45);
            --border-line: rgba(255, 255, 255, 0.08);
            --border-glow: rgba(139, 92, 246, 0.4);
            --shadow-card: 0 4px 20px rgba(0, 0, 0, 0.4);
            --shadow-hover: 0 12px 40px rgba(0, 0, 0, 0.5), 0 0 0 1px var(--border-glow);
            --radius: 18px;
            --gradient-ember: linear-gradient(135deg, #8b5cf6, #a78bfa);
            --gradient-night: radial-gradient(ellipse at top, rgba(139, 92, 246, 0.08), transparent 60%);
        }

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

        html {
            scroll-behavior: smooth;
        }

        body {
            font-family: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', 'Helvetica Neue', sans-serif;
            background: var(--bg-night);
            color: var(--text-primary);
            line-height: 1.7;
            -webkit-font-smoothing: antialiased;
            overflow-x: hidden;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 24px;
        }

        section {
            padding: 84px 0;
            position: relative;
        }

        /* ===== 导航 ===== */
        .header {
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            z-index: 1000;
            background: rgba(13, 13, 18, 0.82);
            backdrop-filter: blur(18px);
            -webkit-backdrop-filter: blur(18px);
            border-bottom: 1px solid var(--border-line);
        }

        .nav-container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 14px 24px;
            display: flex;
            align-items: center;
            justify-content: space-between;
        }

        .logo {
            display: flex;
            align-items: center;
            gap: 10px;
            font-size: 22px;
            font-weight: 800;
            color: var(--text-primary);
            letter-spacing: 0.02em;
        }

        .logo-icon {
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .logo-icon img {
            width: 30px;
            height: 30px;
            border-radius: 8px;
            display: block;
        }

        .nav-menu {
            display: flex;
            gap: 28px;
            list-style: none;
        }

        .nav-menu a {
            color: var(--text-secondary);
            text-decoration: none;
            font-size: 15px;
            font-weight: 500;
            transition: color .2s;
        }

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

        /* ===== Hero ===== */
        .hero {
            min-height: 100vh;
            min-height: 100svh;
            padding: 72px 0 36px;
            text-align: center;
            display: flex;
            align-items: center;
            position: relative;
            overflow: hidden;
            background: var(--gradient-night);
        }

        .hero .container {
            width: 100%;
            position: relative;
            z-index: 1;
        }

        .hero::before {
            content: '';
            position: absolute;
            top: -240px;
            left: 50%;
            transform: translateX(-50%);
            width: 720px;
            height: 720px;
            border-radius: 50%;
            background: radial-gradient(circle, rgba(139, 92, 246, 0.16), transparent 65%);
            pointer-events: none;
            filter: blur(8px);
        }

        .hero::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            right: 0;
            height: 1px;
            background: linear-gradient(90deg, transparent, var(--ember), transparent);
            opacity: 0.5;
        }

        .badge {
            display: inline-block;
            background: var(--ember-light);
            color: var(--ember);
            border: 1px solid var(--border-glow);
            padding: 7px 18px;
            border-radius: 100px;
            font-size: 14px;
            font-weight: 600;
            margin-bottom: 36px;
            position: relative;
        }

        .hero h1 {
            font-size: 38px;
            font-weight: 800;
            line-height: 1.18;
            letter-spacing: -0.025em;
            margin-bottom: 48px;
            position: relative;
        }

        .hero-subtitle {
            font-size: 18px;
            color: var(--text-secondary);
            max-width: 680px;
            margin: 0 auto 44px;
            position: relative;
        }

        .btn-group {
            display: flex;
            gap: 14px;
            justify-content: center;
            position: relative;
        }

        .btn-primary {
            display: inline-block;
            background: var(--gradient-ember);
            color: #fff;
            padding: 16px 80px;
            border-radius: 100px;
            font-size: 24px;
            font-weight: 800;
            text-decoration: none;
            transition: all .25s;
            box-shadow: 0 8px 28px rgba(139, 92, 246, 0.4);
            border: none;
        }

        .btn-primary:hover {
            transform: translateY(-3px);
            box-shadow: 0 14px 36px rgba(139, 92, 246, 0.55);
        }

        /* ===== 图片 ===== */
        .card-img {
            width: 100%;
            height: 150px;
            object-fit: cover;
            border-radius: 12px;
            margin-bottom: 16px;
            display: block;
        }

        .intro-img {
            width: 100%;
            max-width: 820px;
            border-radius: 20px;
            margin: 0 auto 32px;
            display: block;
            box-shadow: var(--shadow-card);
            border: 1px solid var(--border-line);
        }

        /* ===== 暗色表面（嵌套亮卡） ===== */
        .bg-elevated-surface {
            background: var(--bg-night-2);
        }

        /* ===== 标题 ===== */
        .section-title {
            font-size: 38px;
            font-weight: 800;
            letter-spacing: -0.02em;
            line-height: 1.22;
            margin-bottom: 16px;
            text-align: center;
            color: var(--text-primary);
        }

        .section-title .accent {
            color: var(--ember);
        }

        .section-sub {
            font-size: 18px;
            color: var(--text-secondary);
            text-align: center;
            margin-bottom: 52px;
        }

        /* ===== 功能卡片 ===== */
        .grid-3 {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 24px;
        }

        .feature-card {
            background: var(--bg-card);
            border-radius: var(--radius);
            padding: 30px;
            box-shadow: var(--shadow-card);
            border: 1px solid var(--border-line);
            transition: transform .25s, box-shadow .25s, border-color .25s;
        }

        .feature-card:hover {
            transform: translateY(-6px);
            box-shadow: var(--shadow-hover);
            border-color: var(--border-glow);
        }

        .feature-icon {
            width: 50px;
            height: 50px;
            border-radius: 12px;
            background: var(--ember-light);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 24px;
            margin-bottom: 18px;
            border: 1px solid var(--border-glow);
        }

        .feature-card h3 {
            font-size: 20px;
            font-weight: 700;
            margin-bottom: 10px;
            color: var(--text-primary);
        }

        .feature-card p {
            font-size: 15px;
            color: var(--text-secondary);
            line-height: 1.75;
        }

        /* ===== 场景卡片 ===== */
        .case-grid {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 24px;
        }

        .case-item {
            background: var(--bg-elevated);
            border: 1px solid var(--border-line);
            border-radius: var(--radius);
            padding: 30px;
            transition: all .25s;
        }

        .case-item:hover {
            border-color: var(--border-glow);
            background: rgba(249, 115, 22, 0.06);
            transform: translateY(-4px);
        }

        .case-item h3 {
            font-size: 20px;
            font-weight: 700;
            color: var(--text-primary);
            margin-bottom: 10px;
        }

        .case-item p {
            font-size: 15px;
            color: var(--text-secondary);
            line-height: 1.75;
        }

        /* ===== 视频卡片 ===== */
        .video-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
            gap: 24px;
        }

        .video-card {
            background: var(--bg-card);
            border-radius: var(--radius);
            overflow: hidden;
            box-shadow: var(--shadow-card);
            border: 1px solid var(--border-line);
            transition: transform .25s, box-shadow .25s, border-color .25s;
        }

        .video-card:hover {
            transform: translateY(-6px);
            box-shadow: var(--shadow-hover);
            border-color: var(--border-glow);
        }

        .video-wrapper {
            position: relative;
            width: 100%;
            padding-top: 56.25%;
            background: #000;
        }

        .video-wrapper iframe {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            border: none;
        }

        .video-info {
            padding: 22px;
        }

        .video-info h4 {
            font-size: 16px;
            font-weight: 700;
            margin-bottom: 8px;
            line-height: 1.45;
            color: var(--text-primary);
        }

        .video-info p {
            font-size: 14px;
            color: var(--text-secondary);
        }

        /* ===== 步骤卡片 ===== */
        .step-grid {
            display: grid;
            grid-template-columns: repeat(4, 1fr);
            gap: 24px;
        }

        .step-card {
            background: var(--bg-elevated);
            border: 1px solid var(--border-line);
            border-radius: var(--radius);
            padding: 30px;
            text-align: center;
            transition: all .25s;
        }

        .step-card:hover {
            border-color: var(--border-glow);
            transform: translateY(-4px);
        }

        .step-number {
            width: 50px;
            height: 50px;
            border-radius: 50%;
            background: var(--gradient-ember);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 20px;
            font-weight: 800;
            color: #1a1a24;
            margin: 0 auto 18px;
            box-shadow: 0 4px 16px rgba(249, 115, 22, 0.4);
        }

        .step-card h3 {
            font-size: 18px;
            font-weight: 700;
            color: var(--text-primary);
            margin-bottom: 8px;
        }

        .step-card p {
            font-size: 14px;
            color: var(--text-secondary);
            line-height: 1.7;
        }

        /* ===== 优势 ===== */
        .advantage-list {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 24px;
        }

        .advantage-block {
            background: var(--bg-card);
            border-radius: var(--radius);
            padding: 30px;
            box-shadow: var(--shadow-card);
            border-left: 4px solid var(--ember);
            border-top: 1px solid var(--border-line);
            border-right: 1px solid var(--border-line);
            border-bottom: 1px solid var(--border-line);
            transition: all .25s;
        }

        .advantage-block:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-hover);
        }

        .advantage-block h3 {
            font-size: 20px;
            font-weight: 700;
            margin-bottom: 10px;
            color: var(--text-primary);
        }

        .advantage-block p {
            font-size: 15px;
            color: var(--text-secondary);
            line-height: 1.75;
        }

        /* ===== FAQ ===== */
        .faq-item {
            background: var(--bg-card);
            border: 1px solid var(--border-line);
            border-radius: var(--radius);
            padding: 26px 30px;
            margin-bottom: 14px;
            transition: all .25s;
        }

        .faq-item:hover {
            border-color: var(--border-glow);
        }

        .faq-item h3 {
            font-size: 17px;
            font-weight: 700;
            color: var(--text-primary);
            margin-bottom: 10px;
        }

        .faq-item p {
            font-size: 15px;
            color: var(--text-secondary);
            line-height: 1.8;
        }

        /* ===== CTA 按钮 ===== */
        .btn-secondary {
            display: inline-block;
            padding: 16px 44px;
            border-radius: 100px;
            font-size: 16px;
            font-weight: 800;
            text-decoration: none;
            transition: all .25s;
        }

        /* ===== 页脚 ===== */
        .footer {
            background: var(--bg-night-2);
            color: var(--text-muted);
            padding: 50px 0;
            text-align: center;
            border-top: 1px solid var(--border-line);
        }

        .footer p {
            font-size: 14px;
            margin-bottom: 8px;
        }

        /* ===== 响应式 ===== */
        @media (max-width: 900px) {
            .grid-3 {
                grid-template-columns: 1fr;
            }

            .case-grid,
            .advantage-list {
                grid-template-columns: 1fr;
            }

            .step-grid {
                grid-template-columns: repeat(2, 1fr);
            }

            .nav-menu {
                display: none;
            }

            .hero h1 {
                font-size: 38px;
            }

            .section-title {
                font-size: 28px;
            }

            section {
                padding: 56px 0;
            }

            .hero {
                padding: 72px 0 24px;
            }

            .badge {
                margin-bottom: 30px;
            }

            .hero-subtitle {
                max-width: 680px;
                margin-bottom: 38px;
                font-size: 16px;
                line-height: 1.6;
            }

            .btn-primary {
                padding: 14px 56px;
                font-size: 20px;
            }
        }

        @media (max-width: 900px) and (max-height: 720px) {
            .hero {
                padding: 66px 0 20px;
            }

            .badge {
                padding: 5px 14px;
                margin-bottom: 22px;
                font-size: 13px;
            }

            .hero h1 {
                margin-bottom: 28px;
                font-size: 30px;
                line-height: 1.1;
            }

            .hero-subtitle {
                margin-bottom: 28px;
                font-size: 14px;
                line-height: 1.45;
            }

            .btn-primary {
                padding: 12px 40px;
                font-size: 18px;
            }

            .hero .btn-group + div {
                margin-top: 34px !important;
                font-size: 12px !important;
                line-height: 1.4;
            }

        }

        @media (min-width: 901px) and (max-height: 820px) {
            .hero {
                padding: 66px 0 26px;
            }

            .badge {
                margin-bottom: 28px;
            }

            .hero h1 {
                margin-bottom: 36px;
                font-size: 34px;
            }

            .hero-subtitle {
                margin-bottom: 34px;
                font-size: 16px;
                line-height: 1.55;
            }

            .btn-primary {
                padding: 12px 56px;
                font-size: 20px;
            }

            .hero .btn-group + div {
                margin-top: 40px !important;
            }

        }