:root {
            --bg-color: #ffffff;
            --text-main: #1a1a2e;
            --text-muted: #4a5568;
            --brand-color: #1a73e8;
            --brand-hover: #1557b0;
            --brand-light: #e8f0fe;
            --surface-light: #f7f8fa;
            --border-color: #e2e8f0;
            --accent-green: #10b981;
            --accent-warm: #f59e0b;
            --card-shadow: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.06);
            --card-shadow-hover: 0 10px 25px rgba(26, 115, 232, 0.08), 0 4px 10px rgba(0, 0, 0, 0.04);
            --radius-sm: 8px;
            --radius-md: 12px;
            --radius-lg: 16px;
        }

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

        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
            color: var(--text-main);
            background-color: var(--bg-color);
            line-height: 1.7;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }

        header {
            border-bottom: 1px solid var(--border-color);
            position: sticky;
            top: 0;
            background: rgba(255, 255, 255, 0.92);
            backdrop-filter: blur(12px);
            -webkit-backdrop-filter: blur(12px);
            z-index: 100;
            box-shadow: 0 1px 0 rgba(0, 0, 0, 0.02);
        }

        .nav-container {
            max-width: 1200px;
            margin: 0 auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 14px 24px;
        }

        .logo-box {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
            transition: opacity 0.2s;
        }

        .logo-box:hover {
            opacity: 0.85;
        }

        .logo-box svg {
            width: 30px;
            height: 30px;
            fill: var(--brand-color);
        }

        .logo-text {
            font-size: 20px;
            font-weight: 700;
            color: var(--brand-color);
            letter-spacing: -0.3px;
        }

        nav {
            display: flex;
            gap: 28px;
        }

        nav a {
            text-decoration: none;
            color: var(--text-muted);
            font-weight: 500;
            transition: color 0.2s;
            font-size: 14.5px;
            position: relative;
        }

        nav a:hover,
        nav a.active {
            color: var(--brand-color);
        }

        nav a.active::after {
            content: '';
            position: absolute;
            bottom: -6px;
            left: 0;
            right: 0;
            height: 2px;
            background: var(--brand-color);
            border-radius: 1px;
        }

        /* 英雄区域 */
        .security-hero {
            max-width: 860px;
            margin: 0 auto;
            text-align: center;
            padding: 64px 24px 32px 24px;
        }

        .security-hero h1 {
            font-size: 42px;
            font-weight: 800;
            letter-spacing: -1.2px;
            margin-bottom: 18px;
            color: #0f172a;
            line-height: 1.25;
        }

        .security-hero p {
            font-size: 17px;
            color: var(--text-muted);
            max-width: 680px;
            margin: 0 auto;
            line-height: 1.75;
        }

        /* 核心安全盾牌区 */
        .shield-section {
            max-width: 1200px;
            margin: 0 auto;
            padding: 20px 24px 60px 24px;
        }

        .shield-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 28px;
        }

        @media (max-width: 768px) {
            .shield-grid {
                grid-template-columns: 1fr;
            }
            .security-hero h1 {
                font-size: 32px;
            }
            nav {
                display: none;
            }
        }

        .shield-card {
            background: #fff;
            border: 1px solid var(--border-color);
            border-radius: var(--radius-md);
            padding: 36px 28px;
            text-align: center;
            transition: transform 0.25s, box-shadow 0.25s;
            box-shadow: var(--card-shadow);
        }

        .shield-card:hover {
            transform: translateY(-5px);
            box-shadow: var(--card-shadow-hover);
            border-color: #cbd5e1;
        }

        .shield-icon {
            width: 64px;
            height: 64px;
            background: var(--brand-light);
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0 auto 20px auto;
            color: var(--brand-color);
        }

        .shield-card h3 {
            font-size: 20px;
            font-weight: 700;
            margin-bottom: 12px;
            color: #0f172a;
        }

        .shield-card p {
            font-size: 14px;
            color: var(--text-muted);
            line-height: 1.65;
        }

        /* 加密流程可视化 */
        .flow-section {
            background: #fafbfc;
            border-top: 1px solid var(--border-color);
            border-bottom: 1px solid var(--border-color);
            padding: 64px 24px;
        }

        .flow-container {
            max-width: 1000px;
            margin: 0 auto;
        }

        .flow-title {
            text-align: center;
            font-size: 28px;
            font-weight: 700;
            margin-bottom: 40px;
            color: #0f172a;
        }

        .flow-steps {
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            gap: 20px;
        }

        @media (max-width: 768px) {
            .flow-steps {
                flex-direction: column;
                gap: 32px;
            }
        }

        .flow-step {
            flex: 1;
            min-width: 180px;
            text-align: center;
            position: relative;
        }

        .flow-step::after {
            content: '';
            position: absolute;
            top: 24px;
            right: -30px;
            width: 40px;
            height: 2px;
            background: var(--brand-color);
            opacity: 0.3;
        }

        .flow-step:last-child::after {
            display: none;
        }

        @media (max-width: 768px) {
            .flow-step::after {
                display: none;
            }
        }

        .step-circle {
            width: 48px;
            height: 48px;
            background: var(--brand-color);
            color: #fff;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: 700;
            font-size: 18px;
            margin: 0 auto 12px auto;
            box-shadow: 0 4px 12px rgba(26, 115, 232, 0.3);
        }

        .flow-step h4 {
            font-size: 16px;
            font-weight: 600;
            margin-bottom: 6px;
            color: #0f172a;
        }

        .flow-step p {
            font-size: 13px;
            color: var(--text-muted);
        }

        /* 隐私控制面板展示 */
        .privacy-dashboard {
            max-width: 1200px;
            margin: 0 auto;
            padding: 64px 24px;
        }

        .dashboard-title {
            text-align: center;
            font-size: 28px;
            font-weight: 700;
            margin-bottom: 16px;
            color: #0f172a;
        }

        .dashboard-subtitle {
            text-align: center;
            font-size: 15px;
            color: var(--text-muted);
            max-width: 600px;
            margin: 0 auto 48px auto;
        }

        .toggle-list {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 24px;
        }

        @media (max-width: 640px) {
            .toggle-list {
                grid-template-columns: 1fr;
            }
        }

        .toggle-item {
            background: #fff;
            border: 1px solid var(--border-color);
            border-radius: var(--radius-sm);
            padding: 24px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            box-shadow: var(--card-shadow);
            transition: box-shadow 0.2s;
        }

        .toggle-item:hover {
            box-shadow: var(--card-shadow-hover);
        }

        .toggle-info h4 {
            font-size: 16px;
            font-weight: 600;
            margin-bottom: 4px;
            color: #0f172a;
        }

        .toggle-info p {
            font-size: 13px;
            color: var(--text-muted);
        }

        .toggle-switch {
            width: 48px;
            height: 26px;
            background: var(--accent-green);
            border-radius: 13px;
            position: relative;
            flex-shrink: 0;
        }

        .toggle-switch::after {
            content: '';
            position: absolute;
            top: 3px;
            right: 3px;
            width: 20px;
            height: 20px;
            background: #fff;
            border-radius: 50%;
            box-shadow: 0 1px 3px rgba(0, 0, 0, 0.2);
        }

        /* 对比表格 */
        .compare-section {
            background: #fafbfc;
            border-top: 1px solid var(--border-color);
            padding: 64px 24px;
        }

        .compare-container {
            max-width: 1000px;
            margin: 0 auto;
        }

        .compare-title {
            text-align: center;
            font-size: 28px;
            font-weight: 700;
            margin-bottom: 40px;
            color: #0f172a;
        }

        .compare-table {
            width: 100%;
            border-collapse: collapse;
            background: #fff;
            border-radius: var(--radius-md);
            overflow: hidden;
            box-shadow: var(--card-shadow);
        }

        .compare-table th {
            background: var(--brand-light);
            color: var(--brand-color);
            padding: 16px;
            font-weight: 600;
            font-size: 14px;
            text-align: left;
        }

        .compare-table td {
            padding: 14px 16px;
            font-size: 14px;
            border-bottom: 1px solid var(--border-color);
            color: var(--text-main);
        }

        .compare-table tr:last-child td {
            border-bottom: none;
        }

        .badge-yes {
            display: inline-block;
            background: #d1fae5;
            color: #065f46;
            padding: 2px 10px;
            border-radius: 12px;
            font-weight: 600;
            font-size: 12px;
        }

        .badge-no {
            display: inline-block;
            background: #fee2e2;
            color: #991b1b;
            padding: 2px 10px;
            border-radius: 12px;
            font-weight: 600;
            font-size: 12px;
        }

        /* 页脚 */
        footer {
            border-top: 1px solid var(--border-color);
            padding: 64px 24px 36px 24px;
            background-color: #111827;
            color: #9ca3af;
        }

        .footer-grid {
            max-width: 1200px;
            margin: 0 auto 52px auto;
            display: grid;
            grid-template-columns: 2fr repeat(4, 1fr);
            gap: 36px;
        }

        @media (max-width: 900px) {
            .footer-grid {
                grid-template-columns: repeat(2, 1fr);
            }
        }

        @media (max-width: 480px) {
            .footer-grid {
                grid-template-columns: 1fr;
            }
        }

        .footer-brand h4 {
            color: #fff;
            font-size: 17px;
            margin-bottom: 14px;
            display: flex;
            align-items: center;
            gap: 8px;
            font-weight: 700;
        }

        .footer-brand h4 svg {
            width: 22px;
            height: 22px;
            fill: var(--brand-color);
        }

        .footer-brand p {
            font-size: 13.5px;
            line-height: 1.7;
            color: #9ca3af;
        }

        .footer-col h5 {
            color: #fff;
            font-size: 14px;
            margin-bottom: 18px;
            font-weight: 600;
            letter-spacing: 0.2px;
        }

        .footer-col ul {
            list-style: none;
        }

        .footer-col ul li {
            margin-bottom: 10px;
        }

        .footer-col ul li a {
            color: #9ca3af;
            text-decoration: none;
            font-size: 13.5px;
            transition: color 0.2s;
        }

        .footer-col ul li a:hover {
            color: #fff;
        }

        .footer-bottom {
            max-width: 1200px;
            margin: 0 auto;
            padding-top: 26px;
            border-top: 1px solid #1f2937;
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-size: 13px;
        }

        @media (max-width: 640px) {
            .footer-bottom {
                flex-direction: column;
                gap: 14px;
                text-align: center;
            }
        }

        .footer-bottom-links {
            display: flex;
            gap: 20px;
            flex-wrap: wrap;
        }

        .footer-bottom-links a {
            color: #9ca3af;
            text-decoration: none;
            font-size: 13px;
            transition: color 0.2s;
        }

        .footer-bottom-links a:hover {
            color: #fff;
        }