:root {
            --bg: #ffffff;
            --surface: #f8fafc;
            --surface-alt: #f1f5f9;
            --text: #0f172a;
            --text-secondary: #475569;
            --text-muted: #64748b;
            --accent: #2563eb;
            --accent-light: #3b82f6;
            --accent-glow: rgba(37, 99, 235, 0.08);
            --border: #e2e8f0;
            --border-light: #f1f5f9;
            --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04);
            --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.06);
            --shadow-lg: 0 20px 48px rgba(0, 0, 0, 0.08);
            --shadow-xl: 0 32px 64px rgba(0, 0, 0, 0.1);
            --radius-sm: 12px;
            --radius: 20px;
            --radius-lg: 28px;
            --radius-xl: 36px;
            --transition: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
            --font-sans: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
            --gradient-hero: linear-gradient(135deg, #2563eb 0%, #06b6d4 50%, #3b82f6 100%);
            --gradient-cta: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0f172a 100%);
            --gradient-card: linear-gradient(160deg, #ffffff 0%, #f8fafc 100%);
        }

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

        html {
            scroll-behavior: smooth;
            -webkit-text-size-adjust: 100%;
            text-size-adjust: 100%;
        }

        body {
            font-family: var(--font-sans);
            background: var(--bg);
            color: var(--text);
            line-height: 1.6;
            overflow-x: hidden;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
            text-rendering: optimizeLegibility;
        }

        /* ===== UTILITY ===== */
        .container {
            max-width: 1220px;
            margin: 0 auto;
            padding: 0 28px;
        }

        .sr-only {
            position: absolute;
            width: 1px;
            height: 1px;
            padding: 0;
            margin: -1px;
            overflow: hidden;
            clip: rect(0, 0, 0, 0);
            border: 0;
        }

        /* ===== HEADER ===== */
        header {
            background: rgba(255, 255, 255, 0.88);
            backdrop-filter: blur(18px);
            -webkit-backdrop-filter: blur(18px);
            position: sticky;
            top: 0;
            z-index: 1000;
            border-bottom: 1px solid rgba(0, 0, 0, 0.04);
            transition: var(--transition);
        }

        header.scrolled {
            box-shadow: var(--shadow-md);
            background: rgba(255, 255, 255, 0.95);
        }

        nav {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 16px 0;
            flex-wrap: wrap;
            gap: 14px;
        }

        .logo {
            font-size: 1.75rem;
            font-weight: 800;
            letter-spacing: -0.025em;
            background: var(--gradient-hero);
            -webkit-background-clip: text;
            background-clip: text;
            -webkit-text-fill-color: transparent;
            flex-shrink: 0;
            white-space: nowrap;
        }

        .nav-links {
            display: flex;
            gap: 28px;
            align-items: center;
            flex-wrap: wrap;
            list-style: none;
        }

        .nav-links a {
            text-decoration: none;
            font-weight: 500;
            color: var(--text-secondary);
            transition: var(--transition);
            font-size: 0.95rem;
            position: relative;
            padding: 4px 0;
            white-space: nowrap;
        }

        .nav-links a::after {
            content: '';
            position: absolute;
            bottom: -2px;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--accent);
            border-radius: 2px;
            transition: width var(--transition);
        }

        .nav-links a:hover {
            color: var(--accent);
        }
        .nav-links a:hover::after {
            width: 100%;
        }
        .nav-links a.active {
            color: var(--accent);
            font-weight: 600;
        }
        .nav-links a.active::after {
            width: 100%;
        }

        /* ===== HERO ===== */
        .hero-v2 {
            padding: 80px 0 64px;
            background: radial-gradient(ellipse at 75% 5%, rgba(37, 99, 235, 0.04) 0%, #ffffff 55%),
                radial-gradient(ellipse at 25% 90%, rgba(6, 182, 212, 0.03) 0%, #ffffff 55%);
        }

        .hero-grid-v2 {
            display: flex;
            align-items: stretch;
            gap: 56px;
            flex-wrap: wrap;
        }

        .hero-left {
            flex: 1.25;
            min-width: 300px;
        }

        .hero-badge-v2 {
            background: #eef2ff;
            color: #1e40af;
            display: inline-flex;
            align-items: center;
            gap: 6px;
            padding: 7px 18px;
            border-radius: 40px;
            font-size: 0.82rem;
            font-weight: 600;
            margin-bottom: 20px;
            letter-spacing: 0.01em;
            border: 1px solid rgba(37, 99, 235, 0.12);
        }

        .hero-left h1 {
            font-size: clamp(2.2rem, 4.5vw, 3.5rem);
            font-weight: 800;
            line-height: 1.18;
            letter-spacing: -0.025em;
            margin-bottom: 20px;
            color: #0a0c10;
        }

        .hero-gradient-text {
            background: var(--gradient-hero);
            -webkit-background-clip: text;
            background-clip: text;
            -webkit-text-fill-color: transparent;
        }

        .hero-desc-v2 {
            font-size: 1.1rem;
            color: var(--text-secondary);
            max-width: 560px;
            margin-bottom: 28px;
            line-height: 1.6;
        }

        .hero-stats-v2 {
            display: flex;
            gap: 36px;
            margin: 28px 0 28px;
            flex-wrap: wrap;
        }

        .stat-v2 {
            text-align: left;
        }
        .stat-v2 h3 {
            font-size: 1.9rem;
            font-weight: 800;
            color: var(--text);
            letter-spacing: -0.02em;
        }
        .stat-v2 p {
            color: var(--text-muted);
            font-size: 0.82rem;
            margin-top: 2px;
        }

        .btn-group {
            display: flex;
            gap: 16px;
            flex-wrap: wrap;
        }

        .btn-primary-v2 {
            background: #0f172a;
            color: #ffffff;
            padding: 14px 32px;
            border-radius: 50px;
            font-weight: 600;
            text-decoration: none;
            transition: var(--transition);
            display: inline-flex;
            align-items: center;
            gap: 6px;
            box-shadow: 0 8px 22px rgba(15, 23, 42, 0.12);
            font-size: 0.95rem;
            border: none;
            cursor: pointer;
        }
        .btn-primary-v2:hover {
            background: var(--accent);
            transform: translateY(-3px);
            box-shadow: 0 14px 32px rgba(37, 99, 235, 0.22);
        }

        .btn-outline-v2 {
            background: transparent;
            border: 1.5px solid #cbd5e1;
            color: #1e293b;
            padding: 14px 32px;
            border-radius: 50px;
            font-weight: 600;
            text-decoration: none;
            transition: var(--transition);
            display: inline-flex;
            align-items: center;
            gap: 6px;
            font-size: 0.95rem;
        }
        .btn-outline-v2:hover {
            border-color: var(--accent);
            color: var(--accent);
            background: #f8fafc;
        }

        .hero-right {
            flex: 0.85;
            min-width: 280px;
            background: var(--gradient-card);
            border-radius: var(--radius-xl);
            padding: 30px 26px;
            box-shadow: var(--shadow-lg);
            border: 1px solid rgba(37, 99, 235, 0.1);
            display: flex;
            flex-direction: column;
            justify-content: center;
            gap: 18px;
        }

        .platform-badge {
            display: flex;
            justify-content: center;
            gap: 14px;
            flex-wrap: wrap;
        }
        .platform-badge span {
            background: #eef2ff;
            padding: 7px 16px;
            border-radius: 30px;
            font-weight: 600;
            font-size: 0.85rem;
            color: #1e40af;
        }

        .rating-large {
            text-align: center;
        }
        .stars-large {
            color: #f59e0b;
            font-size: 1.7rem;
            letter-spacing: 3px;
        }

        .spec-mini {
            display: flex;
            justify-content: space-around;
            text-align: center;
            gap: 10px;
            flex-wrap: wrap;
        }
        .spec-mini div {
            font-size: 0.85rem;
            color: var(--text-secondary);
            line-height: 1.4;
        }
        .spec-mini strong {
            color: var(--text);
            font-size: 0.9rem;
        }

        .hero-trust-badge {
            background: #eef2ff;
            border-radius: 20px;
            padding: 14px 16px;
            text-align: center;
            font-size: 0.85rem;
            color: #1e40af;
            font-weight: 500;
            border: 1px dashed rgba(37, 99, 235, 0.2);
        }

        /* ===== SECTION TITLES ===== */
        .section-title-v2 {
            text-align: center;
            font-size: clamp(1.7rem, 3.5vw, 2.3rem);
            font-weight: 700;
            margin-bottom: 16px;
            color: var(--text);
            letter-spacing: -0.02em;
        }
        .section-subtitle {
            text-align: center;
            color: var(--text-muted);
            font-size: 1rem;
            margin-bottom: 52px;
            max-width: 600px;
            margin-left: auto;
            margin-right: auto;
            line-height: 1.5;
        }

        /* ===== FEATURES ===== */
        .features-v2 {
            padding: 80px 0;
            background: var(--surface);
        }

        .feature-cards-v2 {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
            gap: 28px;
        }

        .card-v2 {
            background: #ffffff;
            padding: 30px 22px;
            border-radius: var(--radius-lg);
            box-shadow: var(--shadow-sm);
            border: 1px solid var(--border-light);
            transition: var(--transition);
            position: relative;
            overflow: hidden;
        }
        .card-v2::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 4px;
            background: var(--gradient-hero);
            opacity: 0;
            transition: opacity var(--transition);
            border-radius: 0 0 4px 4px;
        }
        .card-v2:hover {
            transform: translateY(-8px);
            border-color: rgba(37, 99, 235, 0.2);
            box-shadow: var(--shadow-xl);
        }
        .card-v2:hover::before {
            opacity: 1;
        }
        .card-icon {
            font-size: 2.6rem;
            margin-bottom: 16px;
            display: block;
        }
        .card-v2 h3 {
            font-size: 1.35rem;
            margin-bottom: 10px;
            color: var(--text);
            letter-spacing: -0.01em;
        }
        .card-v2 p {
            color: var(--text-muted);
            font-size: 0.92rem;
            line-height: 1.55;
        }

        /* ===== ARCHITECTURE (三层架构) ===== */
        .architecture-section {
            padding: 80px 0;
            background: #ffffff;
        }

        .arch-cards {
            display: flex;
            gap: 24px;
            flex-wrap: wrap;
            justify-content: center;
        }

        .arch-card {
            flex: 1;
            min-width: 260px;
            max-width: 360px;
            background: #ffffff;
            border-radius: var(--radius-lg);
            padding: 32px 24px;
            border: 1px solid var(--border);
            box-shadow: var(--shadow-sm);
            transition: var(--transition);
            position: relative;
            text-align: center;
        }
        .arch-card:hover {
            box-shadow: var(--shadow-lg);
            border-color: rgba(37, 99, 235, 0.25);
            transform: translateY(-6px);
        }
        .arch-card .layer-badge {
            display: inline-block;
            background: #eef2ff;
            color: #1e40af;
            padding: 6px 16px;
            border-radius: 30px;
            font-weight: 700;
            font-size: 0.8rem;
            margin-bottom: 16px;
            letter-spacing: 0.03em;
            text-transform: uppercase;
        }
        .arch-card h3 {
            font-size: 1.4rem;
            margin-bottom: 10px;
            color: var(--text);
        }
        .arch-card p {
            color: var(--text-muted);
            font-size: 0.9rem;
            line-height: 1.55;
        }
        .arch-card .arch-icon {
            font-size: 3rem;
            margin-bottom: 12px;
            display: block;
        }

        /* ===== RULES HIGHLIGHT ===== */
        .rules-highlight {
            padding: 80px 0;
            background: var(--surface);
        }

        .rules-grid {
            display: flex;
            gap: 48px;
            flex-wrap: wrap;
            align-items: center;
        }
        .rules-text {
            flex: 1;
            min-width: 280px;
        }
        .rules-text h2 {
            font-size: clamp(1.6rem, 3vw, 2.1rem);
            font-weight: 700;
            margin-bottom: 18px;
            color: var(--text);
        }
        .rules-text p {
            color: var(--text-secondary);
            margin-bottom: 14px;
            line-height: 1.6;
        }
        .rules-flow {
            flex: 1;
            min-width: 280px;
            background: #ffffff;
            border-radius: var(--radius-xl);
            padding: 28px 22px;
            box-shadow: var(--shadow-md);
            border: 1px solid var(--border-light);
            display: flex;
            flex-direction: column;
            gap: 14px;
        }
        .flow-step {
            display: flex;
            align-items: center;
            gap: 14px;
            padding: 12px 14px;
            background: #f8fafc;
            border-radius: var(--radius-sm);
            font-size: 0.9rem;
            transition: var(--transition);
            border: 1px solid transparent;
        }
        .flow-step:hover {
            border-color: rgba(37, 99, 235, 0.2);
            background: #ffffff;
        }
        .flow-step .step-num {
            width: 36px;
            height: 36px;
            border-radius: 50%;
            background: var(--accent);
            color: #fff;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 0.9rem;
            flex-shrink: 0;
        }
        .flow-step .step-arrow {
            color: var(--accent);
            font-weight: 700;
            flex-shrink: 0;
        }

        /* ===== SCENARIOS ===== */
        .scenarios-section {
            padding: 80px 0;
            background: #ffffff;
        }

        .scenario-cards {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 24px;
        }
        .scenario-card {
            background: #ffffff;
            border-radius: var(--radius-lg);
            padding: 28px 22px;
            border: 1px solid var(--border-light);
            box-shadow: var(--shadow-sm);
            transition: var(--transition);
            text-align: center;
        }
        .scenario-card:hover {
            box-shadow: var(--shadow-lg);
            border-color: rgba(37, 99, 235, 0.2);
            transform: translateY(-5px);
        }
        .scenario-card .sc-icon {
            font-size: 2.8rem;
            margin-bottom: 14px;
            display: block;
        }
        .scenario-card h4 {
            font-size: 1.1rem;
            margin-bottom: 8px;
            color: var(--text);
        }
        .scenario-card p {
            font-size: 0.88rem;
            color: var(--text-muted);
            line-height: 1.5;
        }

        /* ===== SHOWCASE ===== */
        .showcase {
            background: var(--surface);
            padding: 72px 0;
        }
        .showcase-inner {
            display: flex;
            gap: 50px;
            align-items: center;
            flex-wrap: wrap;
        }
        .showcase-text {
            flex: 1;
            min-width: 280px;
        }
        .showcase-text h2 {
            font-size: clamp(1.6rem, 3vw, 2rem);
            margin-bottom: 18px;
            color: var(--text);
        }
        .check-list {
            list-style: none;
            margin: 20px 0;
        }
        .check-list li {
            margin-bottom: 12px;
            display: flex;
            gap: 10px;
            align-items: flex-start;
            color: var(--text-secondary);
            line-height: 1.5;
        }
        .check-icon {
            color: #10b981;
            font-weight: 800;
            font-size: 1.2rem;
            flex-shrink: 0;
            margin-top: 2px;
        }
        .showcase-img {
            flex: 1;
            min-width: 240px;
            background: linear-gradient(135deg, #e2e8f0, #cbd5e1);
            border-radius: var(--radius-xl);
            padding: 44px 28px;
            text-align: center;
            font-size: 2.8rem;
            font-weight: 700;
            color: #1e293b;
            box-shadow: var(--shadow-md);
        }

        /* ===== FAQ PREVIEW ===== */
        .faq-preview {
            padding: 80px 0;
            background: #ffffff;
        }
        .faq-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
            gap: 20px;
            max-width: 900px;
            margin: 0 auto;
        }
        .faq-item {
            background: #f8fafc;
            border-radius: var(--radius);
            padding: 20px 22px;
            border: 1px solid var(--border-light);
            transition: var(--transition);
            cursor: default;
        }
        .faq-item:hover {
            background: #ffffff;
            border-color: rgba(37, 99, 235, 0.18);
            box-shadow: var(--shadow-md);
        }
        .faq-item h4 {
            font-size: 1rem;
            margin-bottom: 6px;
            color: var(--text);
        }
        .faq-item p {
            font-size: 0.88rem;
            color: var(--text-muted);
            line-height: 1.5;
        }

        /* ===== CTA ===== */
        .cta-v2 {
            background: var(--gradient-cta);
            color: #ffffff;
            padding: 72px 0;
            text-align: center;
            position: relative;
            overflow: hidden;
        }
        .cta-v2::before {
            content: '';
            position: absolute;
            top: -40%;
            left: -20%;
            width: 140%;
            height: 180%;
            background: radial-gradient(ellipse at center, rgba(37, 99, 235, 0.2) 0%, transparent 70%);
            pointer-events: none;
        }
        .cta-v2 h2 {
            font-size: clamp(1.5rem, 3vw, 2rem);
            position: relative;
            z-index: 1;
        }
        .cta-v2 p {
            margin: 16px auto 0;
            max-width: 500px;
            opacity: 0.85;
            position: relative;
            z-index: 1;
            font-size: 0.95rem;
            line-height: 1.5;
        }
        .btn-cta-light {
            background: #ffffff;
            color: #0f172a;
            padding: 14px 42px;
            border-radius: 60px;
            font-weight: 700;
            text-decoration: none;
            display: inline-block;
            margin-top: 28px;
            transition: var(--transition);
            position: relative;
            z-index: 1;
            font-size: 0.95rem;
        }
        .btn-cta-light:hover {
            background: #e2e8f0;
            transform: scale(1.03);
            box-shadow: 0 10px 28px rgba(255, 255, 255, 0.2);
        }
        .cta-extra {
            margin-top: 28px;
            font-size: 0.82rem;
            opacity: 0.7;
            position: relative;
            z-index: 1;
        }

        /* ===== FOOTER ===== */
        footer {
            background: #020617;
            color: #94a3b8;
            padding: 52px 0 28px;
        }
        .footer-grid {
            display: flex;
            justify-content: space-between;
            flex-wrap: wrap;
            gap: 36px;
            margin-bottom: 40px;
        }
        .footer-grid>div {
            min-width: 150px;
        }
        .footer-grid h4 {
            color: #ffffff;
            font-size: 0.95rem;
            margin-bottom: 8px;
        }
        .footer-grid ul {
            list-style: none;
        }
        .footer-grid ul li {
            margin-bottom: 6px;
        }
        .footer-grid a {
            color: #94a3b8;
            text-decoration: none;
            font-size: 0.85rem;
            transition: var(--transition);
        }
        .footer-grid a:hover {
            color: #ffffff;
        }
        .footer-bottom {
            border-top: 1px solid #1e293b;
            padding-top: 24px;
            text-align: center;
            font-size: 0.78rem;
            color: #64748b;
        }

        /* ===== RESPONSIVE ===== */
        @media (max-width: 900px) {
            .hero-grid-v2 {
                gap: 36px;
            }
            .hero-left h1 {
                font-size: 2rem;
            }
            .nav-links {
                gap: 16px;
                font-size: 0.85rem;
            }
            .nav-links a {
                font-size: 0.82rem;
            }
            .container {
                padding: 0 16px;
            }
            .arch-cards {
                flex-direction: column;
                align-items: center;
            }
            .arch-card {
                max-width: 100%;
            }
            .rules-grid {
                flex-direction: column;
                gap: 28px;
            }
        }

        @media (max-width: 600px) {
            nav {
                flex-direction: column;
                align-items: flex-start;
                gap: 10px;
            }
            .nav-links {
                width: 100%;
                justify-content: flex-start;
                gap: 12px;
                flex-wrap: wrap;
            }
            .hero-stats-v2 {
                gap: 20px;
            }
            .stat-v2 h3 {
                font-size: 1.5rem;
            }
            .btn-group {
                flex-direction: column;
                gap: 10px;
            }
            .btn-primary-v2,
            .btn-outline-v2 {
                text-align: center;
                justify-content: center;
            }
            .footer-grid {
                gap: 20px;
            }
        }