:root {
            --bg-deep: #050814;
            --bg-card: #0a0f1f;
            --bg-card-hover: #111831;
            --primary: #3b82f6;
            --primary-glow: rgba(59, 130, 246, 0.4);
            --cyan: #06b6d4;
            --cyan-glow: rgba(6, 182, 212, 0.45);
            --emerald: #10b981;
            --emerald-glow: rgba(16, 185, 129, 0.3);
            --amber: #f59e0b;
            --text-primary: #f1f5f9;
            --text-secondary: #cbd5e1;
            --text-muted: #94a3b8;
            --border-subtle: #1e293b;
            --border-card: #243147;
            --border-glow: #334155;
            --radius-sm: 8px;
            --radius-md: 14px;
            --radius-lg: 20px;
            --shadow-card: 0 8px 30px rgba(0, 0, 0, 0.5);
            --shadow-cyan: 0 0 35px rgba(6, 182, 212, 0.15);
            --font-mono: 'SF Mono', 'Fira Code', 'JetBrains Mono', monospace;
            --transition-fast: 0.2s cubic-bezier(0.4, 0, 0.2, 1);
            --transition-spring: 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
        }

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

        html {
            scroll-behavior: smooth;
            -webkit-font-smoothing: antialiased;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
            background-color: var(--bg-deep);
            color: var(--text-primary);
            line-height: 1.65;
            overflow-x: hidden;
        }

        a {
            color: inherit;
            text-decoration: none;
        }

        /* 导航栏 */
        .header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            z-index: 1000;
            background: rgba(5, 8, 20, 0.8);
            backdrop-filter: blur(18px);
            -webkit-backdrop-filter: blur(18px);
            border-bottom: 1px solid var(--border-subtle);
        }
        .nav-container {
            max-width: 1250px;
            margin: 0 auto;
            padding: 0.9rem 1.8rem;
            display: flex;
            align-items: center;
            justify-content: space-between;
        }
        .logo-area {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 1.45rem;
            font-weight: 800;
            color: #ffffff;
            white-space: nowrap;
        }
        .logo-icon {
            width: 28px;
            height: 28px;
            fill: url(#logo-grad);
            filter: drop-shadow(0 0 6px rgba(6, 182, 212, 0.6));
        }
        .logo-area span {
            color: var(--cyan);
        }
        .nav-links {
            display: flex;
            align-items: center;
            gap: 0.3rem;
            flex-wrap: wrap;
        }
        .nav-links a {
            padding: 0.5rem 1rem;
            font-size: 0.9rem;
            font-weight: 500;
            color: var(--text-muted);
            border-radius: 6px;
            transition: all var(--transition-fast);
            white-space: nowrap;
            position: relative;
        }
        .nav-links a:hover,
        .nav-links a.active {
            color: #ffffff;
            background: rgba(255, 255, 255, 0.05);
        }
        .nav-links a.active::after {
            content: '';
            position: absolute;
            bottom: 2px;
            left: 50%;
            transform: translateX(-50%);
            width: 18px;
            height: 2.5px;
            border-radius: 2px;
            background: var(--cyan);
            box-shadow: 0 0 10px var(--cyan-glow);
        }
        .btn-github {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            background: rgba(255, 255, 255, 0.04);
            border: 1px solid var(--border-subtle);
            padding: 0.5rem 1rem;
            border-radius: 8px;
            color: var(--text-secondary) !important;
            font-size: 0.85rem;
            font-weight: 600;
            transition: all var(--transition-fast);
        }
        .btn-github:hover {
            background: rgba(255, 255, 255, 0.12);
            border-color: #475569;
            color: #fff !important;
        }
        .github-icon {
            width: 15px;
            height: 15px;
            fill: currentColor;
        }

        /* 通用区域 */
        .section-padding {
            padding: 70px 1.5rem;
        }
        .section-header {
            text-align: center;
            margin-bottom: 3rem;
        }
        .section-eyebrow {
            display: inline-block;
            font-size: 0.8rem;
            font-weight: 700;
            text-transform: uppercase;
            letter-spacing: 0.12em;
            color: var(--cyan);
            margin-bottom: 0.5rem;
        }
        .section-title {
            font-size: clamp(1.8rem, 4vw, 2.4rem);
            font-weight: 800;
            letter-spacing: -0.02em;
            margin-bottom: 0.8rem;
            color: #ffffff;
        }
        .section-desc {
            color: var(--text-muted);
            max-width: 650px;
            margin: 0 auto;
            font-size: 1rem;
        }

        /* Hero */
        .download-hero {
            padding: 160px 1.5rem 60px;
            text-align: center;
            position: relative;
            background: radial-gradient(circle at 30% 10%, rgba(6, 182, 212, 0.12) 0%, transparent 50%),
                radial-gradient(circle at 70% 80%, rgba(59, 130, 246, 0.08) 0%, transparent 50%),
                var(--bg-deep);
        }
        .download-hero h1 {
            font-size: clamp(2.2rem, 5vw, 3.4rem);
            font-weight: 900;
            letter-spacing: -0.03em;
            background: linear-gradient(180deg, #ffffff 0%, #cbd5e1 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
            margin-bottom: 1.2rem;
        }
        .download-hero p {
            color: var(--text-muted);
            font-size: 1.15rem;
            max-width: 700px;
            margin: 0 auto 2.5rem;
        }
        .badge-free {
            display: inline-flex;
            align-items: center;
            gap: 6px;
            background: rgba(16, 185, 129, 0.1);
            border: 1px solid rgba(16, 185, 129, 0.3);
            border-radius: 30px;
            padding: 6px 16px;
            color: var(--emerald);
            font-weight: 600;
            font-size: 0.85rem;
            margin-bottom: 2rem;
        }

        /* 平台卡片网格 */
        .platform-grid {
            max-width: 1250px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: 1.8rem;
            padding: 0 1.5rem 80px;
        }
        .platform-card {
            background: var(--bg-card);
            border: 1px solid var(--border-card);
            border-radius: var(--radius-md);
            padding: 2rem 1.5rem;
            text-align: center;
            transition: all var(--transition-spring);
            position: relative;
            display: flex;
            flex-direction: column;
            align-items: center;
        }
        .platform-card:hover {
            border-color: var(--cyan);
            background: var(--bg-card-hover);
            transform: translateY(-6px);
            box-shadow: var(--shadow-card), var(--shadow-cyan);
        }
        .platform-icon-wrap {
            width: 56px;
            height: 56px;
            margin-bottom: 1.2rem;
            color: var(--cyan);
        }
        .platform-icon-wrap svg {
            width: 100%;
            height: 100%;
            fill: currentColor;
            filter: drop-shadow(0 0 8px rgba(6, 182, 212, 0.4));
        }
        .platform-card h3 {
            font-size: 1.25rem;
            font-weight: 700;
            margin-bottom: 0.3rem;
            color: #fff;
        }
        .platform-card .version-badge {
            display: inline-block;
            background: rgba(6, 182, 212, 0.15);
            color: var(--cyan);
            font-size: 0.75rem;
            font-weight: 600;
            padding: 2px 10px;
            border-radius: 20px;
            margin-bottom: 1rem;
        }
        .platform-card .file-meta {
            font-size: 0.8rem;
            color: var(--text-muted);
            margin-bottom: 1.5rem;
            line-height: 1.5;
        }
        .btn-platform {
            margin-top: auto;
            width: 100%;
            background: linear-gradient(135deg, #2563eb, #06b6d4);
            color: #fff;
            font-weight: 700;
            padding: 12px 18px;
            border-radius: 8px;
            font-size: 0.9rem;
            transition: all var(--transition-fast);
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 6px;
            border: none;
            cursor: pointer;
        }
        .btn-platform:hover {
            filter: brightness(1.1);
            box-shadow: 0 8px 20px rgba(37, 99, 235, 0.4);
        }
        .btn-platform.ios-store {
            background: linear-gradient(135deg, #3b82f6, #8b5cf6);
        }

        /* 为什么选择官方下载 */
        .why-official {
            background: var(--bg-card);
            border-top: 1px solid var(--border-subtle);
            border-bottom: 1px solid var(--border-subtle);
        }
        .features-grid {
            max-width: 1100px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 2rem;
        }
        .feature-item {
            text-align: center;
            padding: 2rem 1.5rem;
            background: rgba(255, 255, 255, 0.02);
            border-radius: var(--radius-md);
            border: 1px solid transparent;
            transition: border var(--transition-fast);
        }
        .feature-item:hover {
            border-color: var(--border-glow);
        }
        .feature-icon {
            font-size: 2.5rem;
            margin-bottom: 1rem;
        }
        .feature-item h4 {
            font-size: 1.15rem;
            font-weight: 700;
            margin-bottom: 0.5rem;
            color: #fff;
        }
        .feature-item p {
            color: var(--text-muted);
            font-size: 0.9rem;
        }

        /* 三步下载指南 */
        .steps-container {
            max-width: 900px;
            margin: 0 auto;
            display: flex;
            gap: 2rem;
            justify-content: center;
            flex-wrap: wrap;
        }
        .step-card {
            flex: 1 1 220px;
            background: var(--bg-card);
            border: 1px solid var(--border-card);
            border-radius: var(--radius-md);
            padding: 2rem 1.5rem;
            text-align: center;
            position: relative;
            transition: var(--transition-spring);
        }
        .step-card:hover {
            border-color: var(--cyan);
            transform: translateY(-4px);
        }
        .step-number {
            width: 40px;
            height: 40px;
            background: linear-gradient(135deg, var(--primary), var(--cyan));
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 800;
            color: #fff;
            margin: 0 auto 1rem;
            font-size: 1.2rem;
            box-shadow: 0 0 18px rgba(6, 182, 212, 0.4);
        }
        .step-card h4 {
            font-weight: 700;
            margin-bottom: 0.5rem;
            color: #fff;
        }
        .step-card p {
            color: var(--text-muted);
            font-size: 0.9rem;
        }

        /* 版本历史表格 */
        .changelog-table-wrap {
            max-width: 1000px;
            margin: 0 auto;
            overflow-x: auto;
            border-radius: var(--radius-md);
            border: 1px solid var(--border-card);
        }
        .changelog-table {
            width: 100%;
            border-collapse: collapse;
            font-size: 0.9rem;
            min-width: 650px;
        }
        .changelog-table thead th {
            background: var(--bg-card);
            padding: 1rem 1.2rem;
            text-align: left;
            font-weight: 700;
            color: #fff;
            border-bottom: 1px solid var(--border-card);
        }
        .changelog-table tbody td {
            padding: 0.9rem 1.2rem;
            border-bottom: 1px solid var(--border-subtle);
            color: var(--text-secondary);
        }
        .changelog-table tbody tr:hover td {
            background: rgba(255, 255, 255, 0.02);
        }
        .tag-stable {
            background: rgba(16, 185, 129, 0.15);
            color: var(--emerald);
            padding: 2px 10px;
            border-radius: 20px;
            font-size: 0.75rem;
            font-weight: 600;
        }

        /* 安全校验区块 */
        .verify-box {
            max-width: 1000px;
            margin: 3rem auto 0;
            background: var(--bg-card);
            border: 1px solid var(--border-card);
            border-radius: var(--radius-md);
            padding: 2.2rem;
        }
        .verify-box h3 {
            font-size: 1.3rem;
            margin-bottom: 1rem;
            color: #fff;
            display: flex;
            align-items: center;
            gap: 8px;
        }
        .verify-box p {
            color: var(--text-muted);
            margin-bottom: 1.2rem;
            font-size: 0.95rem;
        }
        .code-block {
            background: #02040a;
            border: 1px solid var(--border-subtle);
            padding: 1.2rem;
            border-radius: 8px;
            font-family: var(--font-mono);
            font-size: 0.85rem;
            color: var(--cyan);
            overflow-x: auto;
            white-space: pre-wrap;
            word-break: break-word;
        }

        /* 常见问题简版 */
        .faq-mini {
            max-width: 800px;
            margin: 3rem auto 0;
            display: flex;
            flex-direction: column;
            gap: 1rem;
        }
        .faq-item {
            background: var(--bg-card);
            border: 1px solid var(--border-card);
            border-radius: var(--radius-sm);
            padding: 1.2rem 1.5rem;
            transition: var(--transition-fast);
        }
        .faq-item:hover {
            border-color: var(--border-glow);
        }
        .faq-item h4 {
            font-weight: 700;
            color: #fff;
            margin-bottom: 0.4rem;
            font-size: 1rem;
        }
        .faq-item p {
            color: var(--text-muted);
            font-size: 0.9rem;
        }

        /* CTA */
        .cta-strip {
            text-align: center;
            padding: 70px 1.5rem;
            background: radial-gradient(circle at 50% 30%, rgba(37, 99, 235, 0.15) 0%, transparent 60%);
        }
        .btn-primary-large {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            background: linear-gradient(135deg, #3b82f6, #06b6d4);
            color: #fff;
            font-weight: 800;
            padding: 16px 40px;
            border-radius: 12px;
            font-size: 1.1rem;
            box-shadow: 0 12px 28px rgba(37, 99, 235, 0.4);
            transition: var(--transition-spring);
        }
        .btn-primary-large:hover {
            transform: translateY(-3px);
            box-shadow: 0 18px 36px rgba(37, 99, 235, 0.55);
        }

        /* 页脚 */
        .footer {
            background: #020308;
            border-top: 1px solid var(--border-subtle);
            padding: 55px 1.5rem 30px;
            font-size: 0.88rem;
            color: var(--text-muted);
        }
        .footer-container {
            max-width: 1250px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: 2fr 1fr 1fr 1.2fr;
            gap: 2rem;
        }
        .footer-col h4 {
            color: var(--text-primary);
            font-weight: 700;
            margin-bottom: 1rem;
        }
        .footer-col ul {
            list-style: none;
        }
        .footer-col ul li {
            margin-bottom: 0.5rem;
        }
        .footer-col a {
            color: var(--text-muted);
            transition: color var(--transition-fast);
        }
        .footer-col a:hover {
            color: #fff;
        }
        .footer-bottom {
            max-width: 1250px;
            margin: 40px auto 0;
            padding-top: 20px;
            border-top: 1px solid rgba(255, 255, 255, 0.04);
            text-align: center;
            font-size: 0.8rem;
            color: var(--text-muted);
        }

        @media (max-width: 900px) {
            .features-grid {
                grid-template-columns: 1fr 1fr;
            }
            .footer-container {
                grid-template-columns: repeat(2, 1fr);
            }
        }
        @media (max-width: 650px) {
            .nav-links {
                display: none;
            }
            .platform-grid {
                grid-template-columns: 1fr;
            }
            .features-grid,
            .steps-container {
                grid-template-columns: 1fr;
            }
            .footer-container {
                grid-template-columns: 1fr;
            }
        }