:root {
            --primary: #0d9488;
            --primary-deep: #0f766e;
            --primary-dark: #115e59;
            --accent: #f97316;
            --accent-glow: #fb923c;
            --surface: #f8fafc;
            --surface-alt: #f0fdfa;
            --text-main: #1e293b;
            --text-soft: #475569;
            --text-muted: #94a3b8;
            --border-light: #e2e8f0;
            --border-subtle: #f1f5f9;
            --white: #ffffff;
            --shadow-card: 0 1px 3px rgba(0, 0, 0, 0.04), 0 8px 24px rgba(0, 0, 0, 0.05);
            --shadow-elevated: 0 4px 16px rgba(0, 0, 0, 0.06), 0 16px 40px rgba(0, 0, 0, 0.07);
            --radius-sm: 10px;
            --radius: 16px;
            --radius-lg: 22px;
            --transition: 0.22s cubic-bezier(0.4, 0, 0.2, 1);
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        html {
            scroll-behavior: smooth;
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
            color: var(--text-main);
            background: linear-gradient(170deg, #f0fdfa 0%, #f8fafc 30%, #fff7ed 70%, #fefce8 100%);
            line-height: 1.7;
            -webkit-font-smoothing: antialiased;
            font-size: 15px;
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }
        a {
            text-decoration: none;
            color: inherit;
            transition: color var(--transition);
        }
        ul {
            list-style: none;
        }
        .container {
            max-width: 1140px;
            margin: 0 auto;
            padding: 0 22px;
        }
        .flex-between {
            display: flex;
            align-items: center;
            justify-content: space-between;
        }

        /* Header 一致 */
        header {
            background: rgba(255, 255, 255, 0.94);
            backdrop-filter: blur(16px);
            -webkit-backdrop-filter: blur(16px);
            position: fixed;
            width: 100%;
            top: 0;
            z-index: 1000;
            box-shadow: 0 1px 0 var(--border-subtle);
            transition: box-shadow var(--transition);
        }
        header.scrolled {
            box-shadow: 0 2px 12px rgba(0, 0, 0, 0.06);
        }
        .nav-container {
            height: 64px;
        }
        .logo {
            font-size: 1.38rem;
            font-weight: 800;
            color: var(--primary-deep);
            letter-spacing: -0.3px;
            display: flex;
            align-items: center;
            gap: 7px;
            white-space: nowrap;
        }
        .logo .rocket-icon {
            display: inline-block;
            font-size: 1.55rem;
            animation: hover-float 2.8s ease-in-out infinite;
        }
        @keyframes hover-float {
            0%,
            100% {
                transform: translateY(0);
            }
            50% {
                transform: translateY(-5px);
            }
        }
        .logo span {
            color: var(--text-main);
            font-weight: 700;
        }
        nav ul {
            display: flex;
            gap: 24px;
            align-items: center;
        }
        nav a {
            font-weight: 500;
            color: var(--text-soft);
            font-size: 0.9rem;
            position: relative;
            padding: 5px 0;
            white-space: nowrap;
        }
        nav a::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--primary);
            border-radius: 2px;
            transition: width var(--transition);
        }
        nav a:hover::after,
        nav a.active::after {
            width: 100%;
        }
        nav a:hover,
        nav a.active {
            color: var(--primary-deep);
        }
        .nav-cta {
            background: var(--primary);
            color: #fff !important;
            padding: 8px 18px !important;
            border-radius: 22px;
            font-weight: 600 !important;
            font-size: 0.86rem !important;
            transition: background var(--transition), transform var(--transition) !important;
            box-shadow: 0 4px 14px rgba(13, 148, 136, 0.25);
        }
        .nav-cta:hover {
            background: var(--primary-deep);
            transform: translateY(-1px);
            box-shadow: 0 6px 20px rgba(13, 148, 136, 0.35);
        }
        .nav-cta::after {
            display: none !important;
        }
        .mobile-menu-btn {
            display: none;
            background: none;
            border: none;
            cursor: pointer;
            padding: 8px;
            flex-direction: column;
            gap: 5px;
            z-index: 1001;
        }
        .mobile-menu-btn span {
            display: block;
            width: 24px;
            height: 2.5px;
            background: var(--text-main);
            border-radius: 3px;
            transition: var(--transition);
        }

        main {
            flex: 1;
            padding: 130px 0 70px;
        }
        .page-header {
            text-align: center;
            margin-bottom: 50px;
        }
        .page-tag {
            display: inline-block;
            padding: 5px 14px;
            background: #f0fdfa;
            color: var(--primary-deep);
            border-radius: 18px;
            font-size: 0.82rem;
            font-weight: 600;
            margin-bottom: 14px;
            letter-spacing: 0.3px;
        }
        .page-header h1 {
            font-size: 2.4rem;
            font-weight: 850;
            margin-bottom: 14px;
            letter-spacing: -0.6px;
            color: var(--text-main);
        }
        .page-header h1 .gradient-text {
            background: linear-gradient(135deg, #0d9488 0%, #0891b2 35%, #f97316 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        .page-subtitle {
            font-size: 1.05rem;
            color: var(--text-soft);
            max-width: 680px;
            margin: 0 auto;
            line-height: 1.7;
        }

        /* 加密层级卡片 */
        .encrypt-layers {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: 20px;
            margin-bottom: 50px;
        }
        .layer-card {
            background: #fff;
            border-radius: var(--radius);
            padding: 26px 20px;
            box-shadow: var(--shadow-card);
            border: 1px solid var(--border-subtle);
            text-align: center;
            transition: all var(--transition);
            position: relative;
        }
        .layer-card::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 40px;
            height: 3px;
            background: var(--primary);
            border-radius: 3px 3px 0 0;
            opacity: 0;
            transition: opacity var(--transition);
        }
        .layer-card:hover {
            transform: translateY(-4px);
            box-shadow: var(--shadow-elevated);
            border-color: #ccfbf1;
        }
        .layer-card:hover::after {
            opacity: 1;
        }
        .layer-icon {
            font-size: 2.4rem;
            margin-bottom: 14px;
        }
        .layer-card h3 {
            font-size: 1.15rem;
            font-weight: 700;
            margin-bottom: 6px;
            color: var(--text-main);
        }
        .layer-card p {
            font-size: 0.85rem;
            color: var(--text-soft);
            line-height: 1.6;
        }

        /* 零日志承诺 */
        .privacy-pledge {
            background: #fff;
            border-radius: var(--radius-lg);
            padding: 40px 28px;
            box-shadow: var(--shadow-card);
            margin-bottom: 50px;
            border: 1px solid var(--border-subtle);
            display: flex;
            flex-wrap: wrap;
            gap: 30px;
            align-items: center;
        }
        .pledge-visual {
            flex: 0 0 120px;
            text-align: center;
        }
        .pledge-icon {
            width: 100px;
            height: 100px;
            border-radius: 50%;
            background: #f0fdfa;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 2.8rem;
            margin: 0 auto 10px;
            border: 4px solid #ccfbf1;
        }
        .pledge-text {
            flex: 1;
            min-width: 250px;
        }
        .pledge-text h2 {
            font-size: 1.7rem;
            font-weight: 750;
            margin-bottom: 12px;
        }
        .pledge-text ul {
            display: flex;
            flex-direction: column;
            gap: 10px;
        }
        .pledge-text ul li {
            display: flex;
            align-items: flex-start;
            gap: 10px;
            font-size: 0.93rem;
            color: var(--text-soft);
        }
        .pledge-text ul li .check {
            color: #10b981;
            font-weight: bold;
            font-size: 1.1rem;
            line-height: 1.4;
        }

        /* 对比表 */
        .compare-table {
            background: #fff;
            border-radius: var(--radius-lg);
            padding: 32px 24px;
            box-shadow: var(--shadow-card);
            margin-bottom: 50px;
            overflow-x: auto;
        }
        .compare-table h2 {
            font-size: 1.6rem;
            font-weight: 750;
            margin-bottom: 20px;
            text-align: center;
        }
        table {
            width: 100%;
            border-collapse: collapse;
            min-width: 600px;
            font-size: 0.9rem;
        }
        th {
            background: var(--surface-alt);
            padding: 14px 16px;
            text-align: left;
            font-weight: 700;
            color: var(--primary-deep);
            border-bottom: 2px solid #ccfbf1;
        }
        td {
            padding: 12px 16px;
            border-bottom: 1px solid var(--border-subtle);
            color: var(--text-soft);
        }
        tr:hover td {
            background: #f8fafc;
        }
        .badge-secure {
            background: #d1fae5;
            color: #065f46;
            padding: 3px 12px;
            border-radius: 12px;
            font-weight: 700;
            font-size: 0.78rem;
        }

        /* 技术原理手风琴 */
        .tech-section {
            margin-bottom: 50px;
        }
        .tech-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 18px;
        }
        .tech-card {
            background: #fff;
            border-radius: var(--radius);
            padding: 20px;
            box-shadow: var(--shadow-card);
            border: 1px solid var(--border-subtle);
            cursor: pointer;
            transition: var(--transition);
        }
        .tech-card:hover {
            border-color: #ccfbf1;
            box-shadow: var(--shadow-elevated);
        }
        .tech-card h4 {
            font-size: 1rem;
            font-weight: 700;
            display: flex;
            align-items: center;
            gap: 8px;
            margin-bottom: 8px;
        }
        .tech-card .tech-body {
            font-size: 0.87rem;
            color: var(--text-soft);
            line-height: 1.6;
            display: none;
        }
        .tech-card.open .tech-body {
            display: block;
        }
        .tech-card .toggle-icon {
            transition: transform 0.3s ease;
            font-size: 1.2rem;
            color: var(--primary);
        }
        .tech-card.open .toggle-icon {
            transform: rotate(45deg);
        }

        /* GitHub入口 */
        .github-banner {
            background: #f0fdfa;
            border: 1px solid #99f6e4;
            border-radius: var(--radius);
            padding: 20px 24px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            gap: 18px;
            margin-top: 40px;
        }
        .github-banner p {
            font-weight: 600;
            color: #0f766e;
        }
        .github-banner a {
            background: var(--primary);
            color: #fff;
            padding: 10px 20px;
            border-radius: 24px;
            font-weight: 600;
            font-size: 0.9rem;
            display: flex;
            align-items: center;
            gap: 8px;
        }
        .github-banner a:hover {
            background: var(--primary-deep);
        }

        footer {
            background: #0f172a;
            color: #94a3b8;
            padding: 50px 0 18px;
            margin-top: auto;
        }
        .footer-grid {
            display: grid;
            grid-template-columns: 2fr 1fr 1fr 1fr;
            gap: 34px;
            margin-bottom: 34px;
            border-bottom: 1px solid #1e293b;
            padding-bottom: 34px;
        }
        .footer-brand h3 {
            color: #fff;
            font-size: 1.3rem;
            margin-bottom: 10px;
            font-weight: 700;
        }
        .footer-brand p {
            line-height: 1.68;
            font-size: 0.87rem;
            max-width: 270px;
            color: #94a3b8;
        }
        .footer-col h4 {
            color: #e2e8f0;
            margin-bottom: 14px;
            font-size: 0.95rem;
            font-weight: 600;
        }
        .footer-col ul li {
            margin-bottom: 8px;
        }
        .footer-col a {
            font-size: 0.86rem;
            color: #94a3b8;
        }
        .footer-col a:hover {
            color: #fff;
        }
        .copyright {
            text-align: center;
            font-size: 0.82rem;
            color: #64748b;
        }

        @media (max-width: 768px) {
            .mobile-menu-btn {
                display: flex;
            }
            nav ul {
                position: fixed;
                top: 0;
                right: -100%;
                width: 260px;
                height: 100vh;
                background: #fff;
                flex-direction: column;
                padding: 78px 28px 28px;
                gap: 18px;
                box-shadow: var(--shadow-elevated);
                transition: right var(--transition);
                z-index: 999;
            }
            nav ul.open {
                right: 0;
            }
            .page-header h1 {
                font-size: 2rem;
            }
            .privacy-pledge {
                flex-direction: column;
                text-align: center;
            }
            .footer-grid {
                grid-template-columns: 1fr 1fr;
                gap: 22px;
            }
            .github-banner {
                flex-direction: column;
                text-align: center;
            }
        }
        @media (max-width: 480px) {
            .page-header h1 {
                font-size: 1.6rem;
            }
            .encrypt-layers,
            .tech-grid {
                grid-template-columns: 1fr;
            }
            .footer-grid {
                grid-template-columns: 1fr;
            }
        }