:root {
            --accent: #4f46e5;
            --accent-dark: #3730a3;
            --accent-light: #eef2ff;
            --accent-glow: rgba(79, 70, 229, 0.10);
            --accent-soft: #f5f3ff;
            --bg: #fafbfc;
            --surface: #ffffff;
            --text: #1a1a2e;
            --text-secondary: #3d3d5c;
            --text-muted: #6b6b80;
            --border: #e2e4ea;
            --border-light: #eff1f5;
            --warm-highlight: #fdfcf8;
            --amber-accent: #6366f1;
            --amber-light: #f5f3ff;
            --shadow-sm: 0 1px 4px rgba(30, 30, 50, 0.04);
            --shadow-md: 0 6px 20px rgba(30, 30, 50, 0.06);
            --shadow-lg: 0 16px 36px rgba(30, 30, 50, 0.09);
            --shadow-xl: 0 24px 48px rgba(30, 30, 50, 0.12);
            --radius-sm: 14px;
            --radius-md: 22px;
            --radius-lg: 34px;
            --radius-xl: 46px;
            --radius-full: 999px;
            --transition: 0.20s cubic-bezier(0.4, 0, 0.2, 1);
            --font-stack: 'Inter', system-ui, -apple-system, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        html {
            scroll-behavior: smooth;
            -webkit-text-size-adjust: 100%;
        }
        body {
            font-family: var(--font-stack);
            background: var(--bg);
            color: var(--text);
            line-height: 1.65;
            font-size: 16px;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
            background-image:
                radial-gradient(ellipse at 12% 8%, rgba(79, 70, 229, 0.025) 0%, transparent 55%),
                radial-gradient(ellipse at 80% 55%, rgba(99, 102, 241, 0.018) 0%, transparent 48%),
                radial-gradient(ellipse at 35% 82%, rgba(79, 70, 229, 0.012) 0%, transparent 42%);
            background-attachment: fixed;
        }
        .container {
            max-width: 1220px;
            margin: 0 auto;
            padding: 0 26px;
        }
        header {
            background: rgba(255, 255, 255, 0.86);
            backdrop-filter: blur(18px);
            -webkit-backdrop-filter: blur(18px);
            position: sticky;
            top: 0;
            z-index: 120;
            border-bottom: 1px solid var(--border-light);
            box-shadow: var(--shadow-sm);
        }
        .nav-bar {
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            padding: 14px 0;
            gap: 10px;
        }
        .logo-area {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
            flex-shrink: 0;
        }
        .logo-icon {
            width: 40px;
            height: 40px;
            background: var(--accent);
            border-radius: 11px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: #fff;
            font-weight: 800;
            font-size: 1.2rem;
            letter-spacing: -0.5px;
            box-shadow: 0 4px 14px rgba(79, 70, 229, 0.28);
        }
        .logo-text {
            font-weight: 780;
            font-size: 1.3rem;
            color: var(--text);
            letter-spacing: -0.35px;
        }
        .logo-text span {
            color: var(--accent);
        }
        .nav-links {
            display: flex;
            gap: 6px;
            align-items: center;
            flex-wrap: wrap;
            font-size: 0.91rem;
        }
        .nav-links a {
            text-decoration: none;
            font-weight: 530;
            color: var(--text-secondary);
            transition: var(--transition);
            padding: 7px 15px;
            border-radius: var(--radius-full);
            white-space: nowrap;
            position: relative;
        }
        .nav-links a:hover,
        .nav-links a.active {
            color: var(--accent);
            background: var(--accent-light);
        }
        .btn-download-nav {
            background: var(--accent) !important;
            color: #fff !important;
            padding: 9px 21px !important;
            border-radius: var(--radius-full) !important;
            font-weight: 600 !important;
            box-shadow: 0 3px 12px rgba(79, 70, 229, 0.24);
            transition: var(--transition) !important;
        }
        .btn-download-nav:hover {
            background: var(--accent-dark) !important;
            transform: translateY(-2px);
            box-shadow: 0 6px 18px rgba(79, 70, 229, 0.32);
        }
        .section {
            padding: 38px 0 44px;
        }
        .section-title {
            text-align: center;
            font-size: clamp(1.55rem, 2.8vw, 2rem);
            font-weight: 750;
            margin-bottom: 10px;
            color: var(--text);
            letter-spacing: -0.3px;
        }
        .section-subtitle {
            text-align: center;
            color: var(--text-muted);
            margin-bottom: 34px;
            font-size: 0.95rem;
            max-width: 580px;
            margin-left: auto;
            margin-right: auto;
        }
        .section-title::after {
            content: '';
            display: block;
            width: 48px;
            height: 3.5px;
            background: var(--accent);
            border-radius: 3px;
            margin: 12px auto 0;
        }

        /* Hero */
        .hero {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 44px;
            padding: 48px 0 42px;
            align-items: start;
        }
        .hero-left .version-badge {
            display: inline-flex;
            align-items: center;
            gap: 7px;
            background: var(--accent-light);
            color: var(--accent);
            font-weight: 640;
            font-size: 0.86rem;
            padding: 6px 15px;
            border-radius: var(--radius-full);
            margin-bottom: 14px;
            letter-spacing: -0.15px;
            animation: pulse-badge 2.6s ease-in-out infinite;
        }
        @keyframes pulse-badge {
            0%,
            100% {
                box-shadow: 0 0 0 0 rgba(79, 70, 229, 0.28);
            }
            50% {
                box-shadow: 0 0 0 12px rgba(79, 70, 229, 0);
            }
        }
        .version-badge .dot {
            width: 9px;
            height: 9px;
            background: #6c63ff;
            border-radius: 50%;
            animation: blink-dot 1.5s ease-in-out infinite;
        }
        @keyframes blink-dot {
            0%,
            100% {
                opacity: 1;
            }
            50% {
                opacity: 0.3;
            }
        }
        .hero-left h1 {
            font-size: clamp(2rem, 4vw, 3rem);
            font-weight: 850;
            line-height: 1.16;
            color: var(--text);
            margin-bottom: 13px;
            letter-spacing: -0.55px;
        }
        .hero-left h1 .accent {
            color: var(--accent);
            position: relative;
            display: inline-block;
        }
        .hero-left h1 .accent::after {
            content: '';
            position: absolute;
            bottom: 2px;
            left: 0;
            width: 100%;
            height: 7px;
            background: rgba(79, 70, 229, 0.16);
            border-radius: 3px;
            z-index: -1;
        }
        .hero-desc {
            font-size: 1.05rem;
            color: var(--text-secondary);
            max-width: 500px;
            margin-bottom: 22px;
            line-height: 1.6;
        }
        .hero-stats {
            display: flex;
            gap: 30px;
            flex-wrap: wrap;
            margin-top: 6px;
        }
        .stat-block h3 {
            font-size: 1.8rem;
            font-weight: 800;
            color: var(--accent);
            line-height: 1.12;
            letter-spacing: -0.25px;
        }
        .stat-block p {
            color: var(--text-muted);
            font-size: 0.83rem;
            margin-top: 2px;
        }
        /* 系统卡片式下载入口 */
        .hero-right {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 13px;
            align-content: start;
        }
        .os-card {
            background: var(--surface);
            border-radius: var(--radius-md);
            padding: 20px 16px;
            border: 1px solid var(--border-light);
            box-shadow: var(--shadow-sm);
            text-decoration: none;
            color: inherit;
            transition: var(--transition);
            display: flex;
            flex-direction: column;
            align-items: center;
            text-align: center;
            gap: 7px;
            position: relative;
            overflow: hidden;
        }
        .os-card:hover {
            border-color: var(--accent);
            box-shadow: var(--shadow-lg);
            transform: translateY(-4px);
        }
        .os-card .os-icon {
            font-size: 2.2rem;
            line-height: 1;
        }
        .os-card .os-name {
            font-weight: 700;
            font-size: 0.95rem;
            color: var(--text);
        }
        .os-card .os-client {
            font-size: 0.78rem;
            color: var(--accent);
            font-weight: 600;
        }
        .os-card .os-ver {
            font-size: 0.72rem;
            color: var(--text-muted);
        }
        .os-card .os-badge {
            display: inline-block;
            padding: 3px 10px;
            border-radius: var(--radius-full);
            font-size: 0.7rem;
            font-weight: 600;
            background: var(--accent-light);
            color: var(--accent);
        }
        .os-card::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 100%;
            height: 3px;
            background: var(--accent);
            transform: scaleX(0);
            transform-origin: left;
            transition: transform 0.3s ease;
            border-radius: 0 0 var(--radius-md) var(--radius-md);
        }
        .os-card:hover::after {
            transform: scaleX(1);
        }

        /* 长内容区 */
        .long-content {
            background: var(--surface);
            border-radius: var(--radius-lg);
            padding: 38px 34px;
            box-shadow: var(--shadow-md);
            border: 1px solid var(--border-light);
            max-width: 900px;
            margin: 0 auto;
        }
        .long-content h3 {
            font-size: 1.22rem;
            font-weight: 700;
            color: var(--accent);
            margin: 22px 0 9px;
            letter-spacing: -0.18px;
        }
        .long-content h3:first-child {
            margin-top: 0;
        }
        .long-content p {
            color: var(--text-secondary);
            margin-bottom: 12px;
            font-size: 0.94rem;
            line-height: 1.7;
        }
        .long-content .highlight-box {
            background: var(--accent-light);
            border-radius: var(--radius-sm);
            padding: 17px 20px;
            margin: 16px 0;
            border-left: 4px solid var(--accent);
            font-size: 0.91rem;
            color: #2a2040;
            line-height: 1.6;
        }

        /* 卡片网格 */
        .card-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(235px, 1fr));
            gap: 18px;
        }
        .eco-card {
            background: var(--surface);
            border-radius: var(--radius-md);
            padding: 26px 21px;
            box-shadow: var(--shadow-sm);
            border: 1px solid var(--border-light);
            transition: var(--transition);
            text-decoration: none;
            color: inherit;
            display: flex;
            flex-direction: column;
            gap: 9px;
            position: relative;
            overflow: hidden;
        }
        .eco-card::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 100%;
            height: 3.5px;
            background: var(--accent);
            transform: scaleX(0);
            transform-origin: left;
            transition: transform 0.3s ease;
            border-radius: 0 0 var(--radius-md) var(--radius-md);
        }
        .eco-card:hover::after {
            transform: scaleX(1);
        }
        .eco-card:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-lg);
            border-color: var(--accent);
        }
        .eco-card .card-icon {
            font-size: 2rem;
            line-height: 1;
        }
        .eco-card h4 {
            font-size: 1.15rem;
            font-weight: 700;
            color: var(--text);
        }
        .eco-card p {
            font-size: 0.88rem;
            color: var(--text-secondary);
            flex: 1;
            line-height: 1.5;
        }
        .eco-card .card-link-text {
            font-weight: 620;
            color: var(--accent);
            display: flex;
            align-items: center;
            gap: 4px;
            font-size: 0.88rem;
            margin-top: auto;
        }

        /* 教程卡片 */
        .tutorial-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 14px;
        }
        .tutorial-card {
            background: var(--surface);
            border-radius: var(--radius-md);
            padding: 18px 16px;
            border: 1px solid var(--border-light);
            text-decoration: none;
            color: inherit;
            transition: var(--transition);
            display: flex;
            align-items: flex-start;
            gap: 11px;
            box-shadow: var(--shadow-sm);
        }
        .tutorial-card:hover {
            border-color: var(--accent);
            box-shadow: var(--shadow-md);
            transform: translateX(3px);
        }
        .tutorial-card .tut-num {
            font-weight: 800;
            font-size: 1.5rem;
            color: var(--accent);
            opacity: 0.7;
            line-height: 1;
            flex-shrink: 0;
            min-width: 28px;
        }
        .tutorial-card .tut-info h4 {
            font-size: 0.95rem;
            font-weight: 650;
            color: var(--text);
            margin-bottom: 3px;
        }
        .tutorial-card .tut-info p {
            font-size: 0.8rem;
            color: var(--text-muted);
            line-height: 1.4;
        }

        /* FAQ */
        .faq-list {
            max-width: 780px;
            margin: 0 auto;
            display: flex;
            flex-direction: column;
            gap: 9px;
        }
        .faq-list details {
            background: var(--surface);
            border-radius: var(--radius-md);
            border: 1px solid var(--border-light);
            padding: 5px 18px;
            transition: var(--transition);
            box-shadow: var(--shadow-sm);
        }
        .faq-list details[open] {
            border-color: var(--accent);
            box-shadow: var(--shadow-md);
            padding-bottom: 14px;
        }
        .faq-list summary {
            font-weight: 650;
            font-size: 0.98rem;
            cursor: pointer;
            padding: 15px 0;
            color: var(--text);
            list-style: none;
            display: flex;
            align-items: center;
            justify-content: space-between;
            letter-spacing: -0.12px;
            outline: none;
        }
        .faq-list summary::-webkit-details-marker {
            display: none;
        }
        .faq-list summary::after {
            content: '+';
            font-size: 1.4rem;
            font-weight: 300;
            color: var(--accent);
            transition: transform 0.3s ease;
            flex-shrink: 0;
            margin-left: 11px;
        }
        .faq-list details[open] summary::after {
            content: '−';
            transform: rotate(180deg);
        }
        .faq-list .faq-answer {
            font-size: 0.88rem;
            color: var(--text-secondary);
            line-height: 1.6;
            padding: 3px 0 7px;
        }

        /* 流量决策引擎 */
        .flow-visual {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: center;
            gap: 10px;
            padding: 20px 8px;
        }
        .flow-node {
            background: var(--surface);
            border-radius: var(--radius-md);
            padding: 16px 20px;
            border: 1.5px solid var(--border);
            text-align: center;
            font-weight: 650;
            font-size: 0.9rem;
            color: var(--text);
            box-shadow: var(--shadow-sm);
            min-width: 90px;
            transition: var(--transition);
        }
        .flow-node.accent-node {
            border-color: var(--accent);
            background: var(--accent-light);
            color: var(--accent);
        }
        .flow-arrow {
            font-size: 1.4rem;
            color: var(--accent);
            font-weight: 700;
            flex-shrink: 0;
        }
        .flow-sub {
            display: flex;
            flex-wrap: wrap;
            gap: 6px;
            justify-content: center;
        }
        .flow-tag {
            display: inline-block;
            padding: 5px 12px;
            border-radius: var(--radius-full);
            font-size: 0.76rem;
            font-weight: 600;
            background: var(--accent-soft);
            color: var(--accent);
            border: 1px solid var(--accent-light);
            white-space: nowrap;
        }

        /* 场景标签 */
        .scene-tags {
            display: flex;
            flex-wrap: wrap;
            gap: 9px;
            justify-content: center;
            margin-bottom: 18px;
        }
        .scene-tag {
            background: var(--surface);
            border: 1px solid var(--border);
            padding: 7px 17px;
            border-radius: var(--radius-full);
            font-size: 0.85rem;
            font-weight: 530;
            color: var(--text-secondary);
            transition: var(--transition);
            cursor: default;
            white-space: nowrap;
        }
        .scene-tag:hover {
            border-color: var(--accent);
            color: var(--accent);
            background: var(--accent-light);
        }

        /* CTA */
        .cta-section {
            background: linear-gradient(115deg, #1a1830 0%, #1f1d3d 40%, #1c1a35 100%);
            border-radius: var(--radius-xl);
            padding: 46px 32px;
            margin: 38px auto 34px;
            text-align: center;
            color: #fff;
            box-shadow: var(--shadow-xl);
            position: relative;
            overflow: hidden;
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
        }
        .cta-section::before {
            content: '';
            position: absolute;
            top: -55px;
            right: -55px;
            width: 190px;
            height: 190px;
            background: radial-gradient(circle, rgba(99, 102, 241, 0.32) 0%, transparent 70%);
            border-radius: 50%;
            pointer-events: none;
        }
        .cta-section::after {
            content: '';
            position: absolute;
            bottom: -35px;
            left: -35px;
            width: 150px;
            height: 150px;
            background: radial-gradient(circle, rgba(255, 255, 255, 0.05) 0%, transparent 70%);
            border-radius: 50%;
            pointer-events: none;
        }
        .cta-section h2,
        .cta-section p,
        .cta-section .btn-cta {
            max-width: 580px;
            position: relative;
            z-index: 1;
        }
        .cta-section h2 {
            font-size: clamp(1.5rem, 2.8vw, 2.1rem);
            font-weight: 800;
            margin-bottom: 11px;
            letter-spacing: -0.25px;
        }
        .cta-section p {
            font-size: 1.02rem;
            opacity: 0.87;
            margin-bottom: 28px;
        }
        .btn-cta {
            background: #fff;
            color: #1a1830;
            padding: 14px 40px;
            border-radius: var(--radius-full);
            font-weight: 700;
            text-decoration: none;
            font-size: 1.03rem;
            transition: var(--transition);
            display: inline-flex;
            align-items: center;
            gap: 9px;
            box-shadow: 0 7px 26px rgba(0, 0, 0, 0.18);
        }
        .btn-cta:hover {
            background: #f2f0ff;
            transform: scale(1.03);
            box-shadow: 0 13px 32px rgba(0, 0, 0, 0.26);
        }

        /* 设备推荐区 */
        .device-recommend {
            background: var(--surface);
            border-radius: var(--radius-lg);
            padding: 28px 26px;
            border: 1px solid var(--border-light);
            box-shadow: var(--shadow-md);
            text-align: center;
            max-width: 680px;
            margin: 0 auto;
        }
        .device-recommend .detected-os {
            font-size: 1.4rem;
            font-weight: 700;
            color: var(--accent);
            margin-bottom: 6px;
        }
        .device-recommend .rec-client {
            font-size: 1.1rem;
            font-weight: 650;
            color: var(--text);
            margin-bottom: 4px;
        }
        .device-recommend .rec-desc {
            font-size: 0.88rem;
            color: var(--text-muted);
            margin-bottom: 16px;
        }
        .device-recommend .btn-rec {
            display: inline-flex;
            align-items: center;
            gap: 7px;
            background: var(--accent);
            color: #fff;
            padding: 11px 26px;
            border-radius: var(--radius-full);
            text-decoration: none;
            font-weight: 620;
            transition: var(--transition);
            box-shadow: 0 4px 16px rgba(79, 70, 229, 0.26);
        }
        .device-recommend .btn-rec:hover {
            background: var(--accent-dark);
            transform: translateY(-2px);
            box-shadow: 0 8px 22px rgba(79, 70, 229, 0.34);
        }

        /* Footer */
        .footer {
            background: #16152a;
            color: #b8b8cc;
            padding: 40px 0 20px;
            border-radius: var(--radius-lg) var(--radius-lg) 0 0;
        }
        .footer-grid {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            gap: 28px;
        }
        .footer-col h4 {
            color: #fff;
            margin-bottom: 10px;
            font-size: 0.93rem;
            letter-spacing: -0.12px;
        }
        .footer-col a {
            color: #b8b8cc;
            text-decoration: none;
            display: block;
            margin-bottom: 5px;
            font-size: 0.85rem;
            transition: var(--transition);
        }
        .footer-col a:hover {
            color: #fff;
            text-decoration: underline;
            text-underline-offset: 3px;
        }
        .footer-copyright {
            text-align: center;
            padding-top: 26px;
            font-size: 0.8rem;
            border-top: 1px solid #2a2840;
            margin-top: 20px;
            color: #8a8a9c;
        }
        .footer-disclaimer {
            text-align: center;
            font-size: 0.74rem;
            color: #6e6e80;
            margin-top: 8px;
            line-height: 1.5;
        }

        /* Steps row */
        .steps-row {
            display: flex;
            gap: 16px;
            flex-wrap: wrap;
            justify-content: center;
        }
        .step-item {
            flex: 1 1 160px;
            background: var(--surface);
            border-radius: var(--radius-md);
            padding: 20px 14px;
            text-align: center;
            border: 1px solid var(--border-light);
            box-shadow: var(--shadow-sm);
            position: relative;
        }
        .step-num {
            display: inline-block;
            width: 36px;
            height: 36px;
            background: var(--accent);
            color: #fff;
            border-radius: 50%;
            font-weight: 800;
            font-size: 1.1rem;
            line-height: 36px;
            margin-bottom: 9px;
        }
        .step-item h4 {
            font-weight: 700;
            margin-bottom: 4px;
            font-size: 0.93rem;
        }
        .step-item p {
            font-size: 0.81rem;
            color: var(--text-secondary);
        }

        /* Responsive */
        @media (max-width: 900px) {
            .hero {
                grid-template-columns: 1fr;
                gap: 26px;
                padding: 28px 0 24px;
            }
            .hero-right {
                grid-template-columns: 1fr 1fr;
                order: -1;
            }
            .hero-left h1 {
                font-size: 1.75rem;
            }
            .nav-bar {
                flex-direction: column;
                align-items: stretch;
            }
            .nav-links {
                gap: 4px;
                font-size: 0.82rem;
            }
            .nav-links a {
                padding: 6px 11px;
            }
            .long-content {
                padding: 22px 16px;
            }
            .cta-section {
                padding: 28px 16px;
                border-radius: var(--radius-lg);
            }
            .flow-visual {
                flex-direction: column;
                gap: 6px;
            }
            .flow-arrow {
                transform: rotate(90deg);
            }
        }
        @media (max-width: 480px) {
            .hero-right {
                grid-template-columns: 1fr 1fr;
                gap: 8px;
            }
            .os-card {
                padding: 14px 10px;
            }
            .os-card .os-icon {
                font-size: 1.6rem;
            }
            .os-card .os-name {
                font-size: 0.82rem;
            }
            .hero-stats {
                gap: 16px;
            }
            .card-grid {
                grid-template-columns: 1fr;
            }
            .tutorial-grid {
                grid-template-columns: 1fr;
            }
            .container {
                padding: 0 12px;
            }
            .steps-row {
                flex-direction: column;
                align-items: stretch;
            }
        }