/* roulang page: index */
:root {
            --bg-deep: #0A0815;
            --bg-card: rgba(22, 18, 40, 0.6);
            --bg-card-solid: #161228;
            --purple: #A855F7;
            --purple-dark: #7C3AED;
            --cyan: #22D3EE;
            --text-primary: #E8E8F0;
            --text-secondary: #B0B0C0;
            --text-muted: #6A6A7A;
            --border-subtle: rgba(168, 85, 247, 0.15);
            --border-glow: rgba(168, 85, 247, 0.5);
            --radius-lg: 20px;
            --radius-md: 16px;
            --radius-pill: 50px;
            --shadow-card: 0 8px 32px rgba(168, 85, 247, 0.08);
            --shadow-hover: 0 12px 40px rgba(34, 211, 238, 0.15);
            --font-title: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
            --font-body: 'Inter', 'SF Pro Display', 'PingFang SC', 'Microsoft YaHei', sans-serif;
            --max-width: 1200px;
            --nav-height: 72px;
        }
        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }
        html {
            scroll-behavior: smooth;
            background-color: var(--bg-deep);
        }
        body {
            font-family: var(--font-body);
            background-color: var(--bg-deep);
            color: var(--text-secondary);
            line-height: 1.7;
            font-size: 16px;
            -webkit-font-smoothing: antialiased;
            overflow-x: hidden;
            position: relative;
        }
        .container {
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 24px;
        }
        h1, h2, h3, h4 {
            font-family: var(--font-title);
            color: var(--text-primary);
            line-height: 1.3;
            margin: 0;
        }
        h1 {
            font-size: 48px;
            font-weight: 800;
            background: linear-gradient(135deg, #A855F7 0%, #22D3EE 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            line-height: 1.25;
            letter-spacing: -0.5px;
        }
        h2 {
            font-size: 36px;
            font-weight: 700;
            line-height: 1.3;
            margin-bottom: 16px;
        }
        h3 {
            font-size: 22px;
            font-weight: 600;
            line-height: 1.4;
        }
        a {
            color: var(--cyan);
            text-decoration: none;
            transition: color 0.2s;
        }
        a:hover {
            color: var(--purple);
        }
        img {
            max-width: 100%;
            height: auto;
            display: block;
        }
        button, .btn {
            cursor: pointer;
            font-family: var(--font-title);
            font-weight: 600;
            border: none;
            outline: none;
        }
        .btn:focus-visible, a:focus-visible {
            outline: 2px solid var(--cyan);
            outline-offset: 2px;
            border-radius: 4px;
        }

        /* Glass card utility */
        .glass-card {
            background: rgba(22, 18, 40, 0.6);
            backdrop-filter: blur(20px);
            -webkit-backdrop-filter: blur(20px);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-md);
            box-shadow: var(--shadow-card);
            transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
        }
        .glass-card:hover {
            transform: translateY(-6px);
            box-shadow: var(--shadow-hover);
            border-color: rgba(34, 211, 238, 0.4);
        }

        /* Buttons */
        .btn-primary {
            background: linear-gradient(135deg, #A855F7 0%, #7C3AED 100%);
            color: #fff;
            padding: 14px 36px;
            border-radius: var(--radius-pill);
            font-weight: 600;
            font-size: 16px;
            box-shadow: 0 0 24px rgba(168, 85, 247, 0.5);
            transition: all 0.3s ease;
            display: inline-block;
            text-align: center;
            letter-spacing: 0.3px;
        }
        .btn-primary:hover {
            box-shadow: 0 0 40px rgba(168, 85, 247, 0.7);
            transform: scale(1.04);
            color: #fff;
            background: linear-gradient(135deg, #B966FF 0%, #8B4AF0 100%);
        }
        .btn-outline {
            background: transparent;
            border: 2px solid var(--cyan);
            color: var(--cyan);
            padding: 12px 32px;
            border-radius: var(--radius-pill);
            font-weight: 600;
            font-size: 16px;
            transition: all 0.3s ease;
            display: inline-block;
            text-align: center;
        }
        .btn-outline:hover {
            background: rgba(34, 211, 238, 0.1);
            border-color: #4FE0F0;
            color: #fff;
        }
        .btn-lg {
            padding: 18px 48px;
            font-size: 18px;
        }

        /* Navigation */
        .nav-bar {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: var(--nav-height);
            background: rgba(10, 8, 21, 0.85);
            backdrop-filter: blur(20px);
            -webkit-backdrop-filter: blur(20px);
            border-bottom: 1px solid rgba(168, 85, 247, 0.3);
            z-index: 100;
            display: flex;
            align-items: center;
        }
        .nav-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
            width: 100%;
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 24px;
        }
        .logo {
            font-family: var(--font-title);
            font-size: 22px;
            font-weight: 800;
            background: linear-gradient(135deg, #A855F7 40%, #7C3AED 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            text-decoration: none;
            white-space: nowrap;
        }
        .nav-links {
            display: flex;
            gap: 32px;
            align-items: center;
        }
        .nav-links a {
            color: #C0C0D0;
            font-weight: 500;
            font-size: 15px;
            transition: color 0.2s;
            text-decoration: none;
        }
        .nav-links a:hover {
            color: var(--cyan);
        }
        .nav-cta {
            background: linear-gradient(135deg, #A855F7, #7C3AED);
            color: #fff;
            padding: 10px 24px;
            border-radius: 50px;
            font-weight: 600;
            font-size: 14px;
            box-shadow: 0 0 18px rgba(168,85,247,0.45);
            transition: all 0.3s;
            text-decoration: none;
            white-space: nowrap;
        }
        .nav-cta:hover {
            box-shadow: 0 0 32px rgba(168,85,247,0.7);
            color: #fff;
        }
        .hamburger {
            display: none;
            background: none;
            border: none;
            color: #fff;
            font-size: 28px;
            cursor: pointer;
        }
        @media (max-width: 768px) {
            .nav-links {
                display: none;
                position: absolute;
                top: var(--nav-height);
                left: 0;
                width: 100%;
                background: rgba(10,8,21,0.95);
                flex-direction: column;
                padding: 24px;
                gap: 20px;
                backdrop-filter: blur(20px);
            }
            .nav-links.active {
                display: flex;
            }
            .hamburger {
                display: block;
            }
        }

        /* Hero */
        .hero {
            min-height: 100vh;
            display: flex;
            align-items: center;
            position: relative;
            overflow: hidden;
            padding-top: var(--nav-height);
            background: radial-gradient(circle at 30% 40%, rgba(168,85,247,0.25) 0%, transparent 45%),
            radial-gradient(circle at 70% 60%, rgba(34,211,238,0.15) 0%, transparent 45%),
            var(--bg-deep);
        }
        .hero-grid {
            display: flex;
            align-items: center;
            gap: 48px;
            width: 100%;
            flex-wrap: wrap;
        }
        .hero-text {
            flex: 1 1 50%;
        }
        .hero-text h1 {
            margin-bottom: 20px;
        }
        .hero-sub {
            font-size: 18px;
            color: #B0B0C0;
            margin-bottom: 32px;
            line-height: 1.6;
        }
        .hero-buttons {
            display: flex;
            gap: 16px;
            flex-wrap: wrap;
            margin-bottom: 40px;
        }
        .hero-stats {
            display: flex;
            gap: 32px;
            flex-wrap: wrap;
        }
        .stat-item h3 {
            font-size: 32px;
            background: linear-gradient(135deg, #22D3EE, #A855F7);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            font-weight: 800;
        }
        .hero-visual {
            flex: 1 1 45%;
            display: flex;
            justify-content: center;
            align-items: center;
            position: relative;
        }
        .hero-img {
            max-width: 100%;
            border-radius: var(--radius-lg);
            box-shadow: 0 0 60px rgba(168,85,247,0.3);
            position: relative;
            z-index: 2;
        }
        .glow-ring {
            position: absolute;
            width: 300px;
            height: 300px;
            border-radius: 50%;
            background: conic-gradient(from 0deg, #A855F7, #22D3EE, #A855F7);
            filter: blur(80px);
            opacity: 0.4;
            animation: spin 12s linear infinite;
            z-index: 1;
        }
        @keyframes spin { 100% { transform: rotate(360deg); } }
        .scroll-hint {
            position: absolute;
            bottom: 30px;
            left: 50%;
            transform: translateX(-50%);
            color: var(--cyan);
            font-size: 28px;
            animation: float 2s infinite;
        }
        @keyframes float {
            0%,100% { transform: translateY(0); }
            50% { transform: translateY(-10px); }
        }
        @media (max-width: 768px) {
            h1 { font-size: 34px; }
            .hero-text { flex: 1 1 100%; }
            .hero-visual { flex: 1 1 100%; margin-top: 32px; }
            .glow-ring { width: 200px; height: 200px; }
        }

        /* Sections */
        .section {
            padding: 100px 0;
        }
        .section-dark {
            background: #0C0A1A;
        }
        .section-title {
            text-align: center;
            margin-bottom: 56px;
        }

        /* Advantage 1+2 layout */
        .adv-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 24px;
        }
        .adv-left {
            grid-row: span 2;
            padding: 40px;
        }
        .adv-right {
            padding: 32px;
            display: flex;
            gap: 20px;
            align-items: flex-start;
        }
        .adv-icon {
            font-size: 36px;
            color: var(--cyan);
        }
        @media (max-width: 768px) {
            .adv-grid { grid-template-columns: 1fr; }
            .adv-left { grid-row: span 1; }
        }

        /* Feature split */
        .feature-row {
            display: flex;
            align-items: center;
            gap: 56px;
            margin-bottom: 80px;
        }
        .feature-row.reverse {
            flex-direction: row-reverse;
        }
        .feature-content {
            flex: 1;
        }
        .feature-img {
            flex: 1;
            border-radius: var(--radius-lg);
            box-shadow: 0 0 40px rgba(168,85,247,0.2);
        }
        .feature-list {
            list-style: none;
            margin-top: 24px;
        }
        .feature-list li {
            margin-bottom: 12px;
            display: flex;
            align-items: center;
            gap: 12px;
            color: #C0C0D0;
        }
        @media (max-width: 768px) {
            .feature-row, .feature-row.reverse { flex-direction: column; }
        }

        /* Scenario cards */
        .scenario-grid {
            display: flex;
            gap: 24px;
            flex-wrap: wrap;
        }
        .scenario-card {
            flex: 1 1 280px;
            padding: 28px;
            display: flex;
            flex-direction: column;
        }
        .scenario-card img {
            border-radius: 12px;
            margin-bottom: 20px;
            height: 180px;
            object-fit: cover;
        }

        /* Cases grid */
        .cases-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 24px;
        }
        .case-item {
            padding: 32px;
            text-align: center;
        }
        .case-big-num {
            font-size: 48px;
            font-weight: 800;
            background: linear-gradient(135deg, #22D3EE, #A855F7);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }
        @media (max-width: 768px) {
            .cases-grid { grid-template-columns: 1fr; }
        }

        /* FAQ */
        .faq-item {
            border-bottom: 1px solid rgba(168,85,247,0.1);
            margin-bottom: 12px;
        }
        .faq-question {
            background: none;
            border: none;
            width: 100%;
            text-align: left;
            padding: 20px 8px;
            font-size: 18px;
            font-weight: 600;
            color: #E0E0F0;
            display: flex;
            justify-content: space-between;
            cursor: pointer;
            background: transparent;
        }
        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease, padding 0.3s;
            color: #B0B0C0;
            padding: 0 8px;
        }
        .faq-item.open .faq-answer {
            max-height: 200px;
            padding: 12px 8px 24px;
            background: rgba(168,85,247,0.03);
        }

        /* CTA Banner */
        .cta-banner {
            background: linear-gradient(135deg, #1A1030, #0D0B1E);
            text-align: center;
            padding: 80px 24px;
        }
        .trust-badge {
            margin-top: 20px;
            font-size: 14px;
            color: #9A9AB0;
        }

        /* Footer */
        .footer {
            background: #06040F;
            border-top: 1px solid rgba(168,85,247,0.3);
            padding: 64px 0 24px;
        }
        .footer-grid {
            display: flex;
            gap: 40px;
            flex-wrap: wrap;
            justify-content: space-between;
        }
        .footer-col {
            flex: 1 1 200px;
        }
        .copyright {
            text-align: center;
            margin-top: 48px;
            font-size: 14px;
            color: #6A6A7A;
        }
        @media (max-width: 768px) {
            .section { padding: 64px 0; }
        }