:root {
            --bg: #f6f9fc;
            --surface: #ffffff;
            --surface-alt: #f0f5f9;
            --text: #1a2e3f;
            --text2: #4b6a88;
            --text3: #6a8296;
            --accent: #1a7f8c;
            --accent2: #0f5560;
            --accent-light: #e6f2f5;
            --border: #e1e8f0;
            --border-light: #eef3f8;
            --green: #2ecc71;
            --amber: #f0a030;
            --purple: #6b3fa0;
            --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.03);
            --shadow: 0 8px 28px rgba(0, 0, 0, 0.06);
            --shadow-lg: 0 16px 40px rgba(0, 0, 0, 0.08);
            --radius-sm: 12px;
            --radius: 18px;
            --radius-lg: 24px;
            --radius-xl: 32px;
            --font: 'Inter', 'PingFang SC', 'Microsoft YaHei', sans-serif;
            --font-mono: 'SF Mono', 'JetBrains Mono', 'Consolas', monospace;
            --transition: 0.22s cubic-bezier(0.4, 0, 0.2, 1);
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        body {
            font-family: var(--font);
            background: var(--bg);
            color: var(--text);
            line-height: 1.55;
            -webkit-font-smoothing: antialiased;
            letter-spacing: -0.01em;
        }
        .container {
            max-width: 1260px;
            margin: 0 auto;
            padding: 0 20px;
        }

        /* 导航栏 */
        .navbar {
            background: rgba(255, 255, 255, 0.94);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            border-bottom: 1px solid var(--border);
            position: sticky;
            top: 0;
            z-index: 100;
        }
        .nav-inner {
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            gap: 15px;
            padding: 14px 0;
        }
        .logo {
            font-size: 1.6rem;
            font-weight: 750;
            letter-spacing: -0.5px;
            background: linear-gradient(135deg, #1a7f8c, #0f5560);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            display: flex;
            align-items: center;
            gap: 6px;
        }
        .logo::before {
            content: '⚡';
            font-size: 1.3rem;
            background: none;
            -webkit-background-clip: unset;
            background-clip: unset;
            color: #1a7f8c;
        }
        .nav-links {
            display: flex;
            gap: 4px;
            flex-wrap: wrap;
            align-items: center;
        }
        .nav-links a {
            text-decoration: none;
            font-weight: 550;
            color: var(--text2);
            padding: 8px 15px;
            border-radius: 22px;
            font-size: 0.9rem;
            transition: var(--transition);
            white-space: nowrap;
        }
        .nav-links a:hover,
        .nav-links a.active {
            background: var(--accent-light);
            color: var(--accent);
        }
        .nav-cta {
            background: var(--accent) !important;
            color: #fff !important;
            font-weight: 620 !important;
            padding: 9px 20px !important;
            box-shadow: 0 4px 14px rgba(26, 127, 140, 0.28);
        }
        .nav-cta:hover {
            background: var(--accent2) !important;
            transform: translateY(-1px);
        }

        /* 页面头部 */
        .page-hero {
            background: linear-gradient(150deg, #eef5fc 0%, #ffffff 60%, #f8fafc 100%);
            padding: 56px 0 40px;
            text-align: center;
            border-bottom: 1px solid var(--border-light);
        }
        .page-hero .eyebrow {
            display: inline-flex;
            align-items: center;
            gap: 7px;
            background: var(--accent-light);
            color: var(--accent);
            padding: 5px 14px;
            border-radius: 20px;
            font-size: 0.78rem;
            font-weight: 600;
            letter-spacing: 0.03em;
            margin-bottom: 16px;
        }
        .page-hero h1 {
            font-size: 2.7rem;
            font-weight: 800;
            letter-spacing: -0.8px;
            color: #0c1f2b;
            margin-bottom: 10px;
        }
        .page-hero p {
            font-size: 1.05rem;
            color: var(--text2);
            max-width: 600px;
            margin: 0 auto;
        }

        /* 下载主区域 */
        .download-section {
            padding: 48px 0 30px;
        }

        /* 双平台卡片 + 决策助手 */
        .platform-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 22px;
            margin-bottom: 36px;
        }
        .platform-card {
            background: var(--surface);
            border-radius: var(--radius-lg);
            padding: 30px 26px;
            border: 1px solid var(--border);
            box-shadow: var(--shadow-sm);
            transition: var(--transition);
            display: flex;
            flex-direction: column;
            position: relative;
            overflow: hidden;
        }
        .platform-card::after {
            content: '';
            position: absolute;
            top: -40px;
            right: -40px;
            width: 100px;
            height: 100px;
            border-radius: 50%;
            background: var(--accent-light);
            opacity: 0;
            transition: var(--transition);
            pointer-events: none;
        }
        .platform-card:hover::after {
            opacity: 1;
            transform: scale(2.8);
        }
        .platform-card:hover {
            box-shadow: var(--shadow);
            transform: translateY(-3px);
        }
        .platform-icon {
            font-size: 2.4rem;
            margin-bottom: 10px;
            position: relative;
            z-index: 1;
        }
        .platform-card h2 {
            font-size: 1.6rem;
            font-weight: 700;
            letter-spacing: -0.5px;
            position: relative;
            z-index: 1;
        }
        .version-tag {
            display: inline-block;
            background: var(--accent-light);
            color: var(--accent);
            padding: 4px 14px;
            border-radius: 20px;
            font-size: 0.78rem;
            font-weight: 600;
            margin: 8px 0 14px;
            width: fit-content;
            position: relative;
            z-index: 1;
        }
        .platform-card p {
            color: var(--text2);
            font-size: 0.92rem;
            margin-bottom: 18px;
            flex: 1;
            position: relative;
            z-index: 1;
        }
        .sys-req {
            background: #f8fafc;
            border-radius: 14px;
            padding: 12px 16px;
            font-size: 0.8rem;
            color: var(--text2);
            margin-bottom: 16px;
            border-left: 3px solid var(--accent);
            position: relative;
            z-index: 1;
        }
        .btn-download {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            background: var(--accent);
            color: #fff;
            padding: 14px 26px;
            border-radius: 28px;
            font-weight: 650;
            text-decoration: none;
            font-size: 0.95rem;
            transition: var(--transition);
            border: none;
            cursor: pointer;
            box-shadow: 0 6px 16px rgba(26, 127, 140, 0.25);
            justify-content: center;
            position: relative;
            z-index: 1;
        }
        .btn-download:hover {
            background: var(--accent2);
            transform: translateY(-2px);
            box-shadow: 0 10px 24px rgba(26, 127, 140, 0.35);
        }
        .file-details {
            font-size: 0.76rem;
            color: var(--text3);
            margin-top: 10px;
            text-align: center;
            position: relative;
            z-index: 1;
        }
        .checksum {
            background: #f1f5f9;
            padding: 10px 14px;
            border-radius: 14px;
            font-family: var(--font-mono);
            font-size: 0.7rem;
            word-break: break-all;
            margin-top: 12px;
            color: #3b5c74;
            position: relative;
            z-index: 1;
        }

        /* 下载决策助手 */
        .decision-helper {
            background: var(--surface);
            border-radius: var(--radius-lg);
            padding: 28px 24px;
            border: 1px solid var(--border);
            box-shadow: var(--shadow-sm);
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            gap: 20px;
            margin-bottom: 40px;
        }
        .decision-helper .dh-icon {
            font-size: 2rem;
        }
        .decision-helper .dh-text {
            flex: 1;
            min-width: 200px;
        }
        .decision-helper h3 {
            font-weight: 700;
            font-size: 1.1rem;
            margin-bottom: 4px;
        }
        .decision-helper p {
            color: var(--text2);
            font-size: 0.88rem;
        }
        .decision-helper .dh-links {
            display: flex;
            gap: 12px;
            flex-wrap: wrap;
        }
        .decision-helper .dh-link {
            background: var(--surface-alt);
            padding: 10px 18px;
            border-radius: 22px;
            text-decoration: none;
            font-weight: 550;
            font-size: 0.85rem;
            color: var(--text);
            transition: var(--transition);
            white-space: nowrap;
        }
        .decision-helper .dh-link:hover {
            background: var(--accent-light);
            color: var(--accent);
        }

        /* 安装流程时间线 */
        .install-flow {
            background: var(--surface);
            border-radius: var(--radius-lg);
            padding: 38px 30px;
            border: 1px solid var(--border);
            box-shadow: var(--shadow-sm);
            margin: 40px 0;
        }
        .flow-title {
            text-align: center;
            font-size: 1.9rem;
            font-weight: 750;
            margin-bottom: 6px;
            letter-spacing: -0.5px;
        }
        .flow-sub {
            text-align: center;
            color: var(--text2);
            margin-bottom: 34px;
        }
        .timeline {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 20px;
            position: relative;
        }
        .timeline::before {
            content: '';
            position: absolute;
            top: 40px;
            left: 5%;
            width: 90%;
            height: 2px;
            background: linear-gradient(to right, var(--accent), #a0c4d0);
            opacity: 0.3;
            z-index: 0;
        }
        .step {
            flex: 1 1 170px;
            min-width: 140px;
            text-align: center;
            position: relative;
            z-index: 2;
        }
        .step-icon {
            width: 60px;
            height: 60px;
            border-radius: 50%;
            background: #fff;
            border: 2px solid var(--accent);
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0 auto 12px;
            font-size: 1.7rem;
            box-shadow: 0 6px 18px rgba(26, 127, 140, 0.1);
            transition: var(--transition);
        }
        .step:hover .step-icon {
            transform: scale(1.06);
            border-color: var(--accent2);
            box-shadow: 0 10px 26px rgba(26, 127, 140, 0.22);
        }
        .step h3 {
            font-size: 0.95rem;
            font-weight: 650;
            margin-bottom: 4px;
        }
        .step p {
            font-size: 0.8rem;
            color: var(--text2);
            line-height: 1.4;
        }

        /* 协议兼容性仪表盘 */
        .protocol-dashboard {
            background: var(--surface);
            border-radius: var(--radius-lg);
            padding: 32px 26px;
            border: 1px solid var(--border);
            box-shadow: var(--shadow-sm);
            margin: 40px 0;
            text-align: center;
        }
        .protocol-dashboard h2 {
            font-size: 1.8rem;
            font-weight: 750;
            margin-bottom: 6px;
        }
        .protocol-dashboard .pd-sub {
            color: var(--text2);
            margin-bottom: 28px;
        }
        .protocol-grid {
            display: flex;
            flex-wrap: wrap;
            gap: 14px;
            justify-content: center;
        }
        .protocol-badge {
            background: #f8fafc;
            border: 1px solid var(--border);
            border-radius: 28px;
            padding: 10px 20px;
            font-weight: 600;
            font-size: 0.88rem;
            display: flex;
            align-items: center;
            gap: 8px;
            transition: var(--transition);
        }
        .protocol-badge .p-dot {
            width: 8px;
            height: 8px;
            border-radius: 50%;
        }
        .p-dot-green {
            background: var(--green);
            box-shadow: 0 0 8px rgba(46, 204, 113, 0.4);
        }
        .p-dot-amber {
            background: var(--amber);
            box-shadow: 0 0 8px rgba(240, 160, 48, 0.4);
        }
        .p-dot-purple {
            background: var(--purple);
            box-shadow: 0 0 8px rgba(107, 63, 160, 0.4);
        }
        .protocol-badge:hover {
            border-color: var(--accent);
            background: #fff;
            box-shadow: var(--shadow-sm);
        }

        /* 开发者资源 */
        .dev-resources {
            background: var(--surface-alt);
            border-radius: var(--radius-lg);
            padding: 30px 26px;
            margin: 40px 0;
            display: flex;
            flex-wrap: wrap;
            gap: 20px;
            align-items: center;
            justify-content: space-between;
        }
        .dev-resources h3 {
            font-weight: 700;
            font-size: 1.1rem;
        }
        .dev-links {
            display: flex;
            gap: 14px;
            flex-wrap: wrap;
        }
        .dev-link {
            background: #fff;
            padding: 10px 18px;
            border-radius: 22px;
            text-decoration: none;
            font-weight: 550;
            color: var(--text);
            font-size: 0.85rem;
            border: 1px solid var(--border);
            transition: var(--transition);
        }
        .dev-link:hover {
            border-color: var(--accent);
            color: var(--accent);
        }

        /* 安全与帮助 */
        .tips-area {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 18px;
            margin: 40px 0;
        }
        .tip-card {
            background: var(--surface);
            border-radius: var(--radius);
            padding: 24px 20px;
            border: 1px solid var(--border);
            box-shadow: var(--shadow-sm);
            transition: var(--transition);
        }
        .tip-card:hover {
            box-shadow: var(--shadow);
        }
        .tip-card h4 {
            font-weight: 650;
            margin-bottom: 10px;
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 1rem;
        }
        .tip-card ul {
            list-style: none;
            padding: 0;
            color: var(--text2);
            font-size: 0.88rem;
        }
        .tip-card li {
            margin-bottom: 5px;
        }

        /* 下一步导航 */
        .next-steps {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
            gap: 14px;
            margin: 40px 0;
        }
        .next-step-card {
            background: var(--surface);
            border-radius: var(--radius);
            padding: 22px 18px;
            text-align: center;
            border: 1px solid var(--border);
            text-decoration: none;
            color: var(--text);
            transition: var(--transition);
            box-shadow: var(--shadow-sm);
        }
        .next-step-card:hover {
            border-color: var(--accent);
            box-shadow: var(--shadow);
            transform: translateY(-2px);
        }
        .next-step-card .ns-icon {
            font-size: 1.8rem;
            margin-bottom: 8px;
        }
        .next-step-card h4 {
            font-weight: 650;
            font-size: 0.9rem;
        }

        /* 返回CTA */
        .cta-return {
            text-align: center;
            padding: 38px 20px;
            background: linear-gradient(135deg, #0c2530, #0f2f3b);
            border-radius: var(--radius-xl);
            color: #fff;
            margin: 40px 0 30px;
        }
        .cta-return h2 {
            font-size: 1.7rem;
            font-weight: 750;
            margin-bottom: 10px;
        }
        .cta-return p {
            color: #bcd0df;
            margin-bottom: 20px;
        }
        .btn-return {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            background: #fff;
            color: #0c2530;
            padding: 14px 30px;
            border-radius: 28px;
            font-weight: 650;
            text-decoration: none;
            transition: var(--transition);
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
        }
        .btn-return:hover {
            background: #e6f0f4;
            transform: translateY(-2px);
        }

        /* 页脚 */
        .footer {
            background: #0c1a22;
            color: #8aa0b4;
            padding: 30px 0 20px;
            text-align: center;
            border-radius: 28px 28px 0 0;
            margin-top: 20px;
        }
        .footer-links {
            display: flex;
            justify-content: center;
            gap: 24px;
            flex-wrap: wrap;
            margin-bottom: 14px;
        }
        .footer-links a {
            color: #bcd0df;
            text-decoration: none;
            font-size: 0.85rem;
            transition: var(--transition);
        }
        .footer-links a:hover {
            color: #fff;
        }
        .copyright {
            font-size: 0.72rem;
            color: #6a8296;
        }

        @media (max-width: 768px) {
            .timeline {
                flex-direction: column;
                align-items: center;
                gap: 28px;
            }
            .timeline::before {
                display: none;
            }
            .page-hero h1 {
                font-size: 2rem;
            }
            .nav-inner {
                flex-direction: column;
            }
            .decision-helper {
                flex-direction: column;
                text-align: center;
            }
            .dev-resources {
                flex-direction: column;
                text-align: center;
            }
        }