/* ============ CSS 自定义属性 ============ */
        :root {
            --bg-deep: #06090f;
            --bg-primary: #0b1019;
            --bg-secondary: #111827;
            --bg-card: rgba(22, 27, 40, 0.85);
            --bg-card-hover: rgba(30, 37, 54, 0.92);
            --bg-glass: rgba(255, 255, 255, 0.025);
            --text-primary: #e6edf3;
            --text-secondary: #8b9bb5;
            --text-muted: #5c6d82;
            --accent-sky: #38bdf8;
            --accent-violet: #818cf8;
            --accent-teal: #2dd4bf;
            --accent-amber: #f59e0b;
            --accent-rose: #f472b6;
            --gradient-accent: linear-gradient(135deg, #38bdf8 0%, #818cf8 50%, #a78bfa 100%);
            --gradient-glow: radial-gradient(ellipse at 50% 0%, rgba(56, 189, 248, 0.12) 0%, transparent 70%);
            --border-subtle: rgba(255, 255, 255, 0.06);
            --border-medium: rgba(255, 255, 255, 0.10);
            --border-glow: rgba(56, 189, 248, 0.25);
            --shadow-card: 0 1px 2px rgba(0, 0, 0, 0.4), 0 4px 16px rgba(0, 0, 0, 0.3);
            --shadow-card-hover: 0 2px 4px rgba(0, 0, 0, 0.5), 0 8px 32px rgba(56, 189, 248, 0.08);
            --radius-sm: 8px;
            --radius-md: 14px;
            --radius-lg: 20px;
            --radius-xl: 28px;
            --font-mono: 'SF Mono', 'Cascadia Code', 'JetBrains Mono', 'Consolas', monospace;
            --transition-fast: 0.18s cubic-bezier(0.4, 0, 0.2, 1);
            --transition-smooth: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
            --max-width: 1280px;
        }

        /* ============ 全局重置 ============ */
        *,
        *::before,
        *::after {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }
        html {
            scroll-behavior: smooth;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
            background: var(--bg-deep);
            color: var(--text-primary);
            line-height: 1.65;
            min-height: 100vh;
            background-image:
                radial-gradient(ellipse at 20% 10%, rgba(56, 189, 248, 0.04) 0%, transparent 60%),
                radial-gradient(ellipse at 80% 90%, rgba(129, 140, 248, 0.03) 0%, transparent 60%),
                radial-gradient(ellipse at 50% 50%, rgba(45, 212, 191, 0.02) 0%, transparent 70%);
            background-attachment: fixed;
        }

        /* ============ 顶部导航 ============ */
        header {
            position: sticky;
            top: 0;
            z-index: 100;
            background: rgba(11, 16, 25, 0.82);
            backdrop-filter: blur(18px) saturate(140%);
            -webkit-backdrop-filter: blur(18px) saturate(140%);
            border-bottom: 1px solid var(--border-subtle);
            transition: var(--transition-smooth);
        }
        .header-box {
            max-width: var(--max-width);
            margin: 0 auto;
            display: flex;
            align-items: center;
            justify-content: space-between;
            padding: 0 24px;
            height: 58px;
            gap: 20px;
        }
        .brand-logo {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
            color: var(--text-primary);
            font-weight: 700;
            font-size: 1.08rem;
            letter-spacing: -0.01em;
            white-space: nowrap;
            flex-shrink: 0;
            transition: var(--transition-fast);
        }
        .brand-logo img {
            width: 34px;
            height: 34px;
            border-radius: 8px;
            transition: var(--transition-fast);
        }
        .brand-logo:hover img {
            transform: scale(1.06);
        }
        .brand-dot {
            display: inline-block;
            width: 7px;
            height: 7px;
            border-radius: 50%;
            background: var(--accent-sky);
            box-shadow: 0 0 10px var(--accent-sky);
            animation: dotPulse 2.2s ease-in-out infinite;
            margin-left: 2px;
        }
        @keyframes dotPulse {
            0%,
            100% {
                box-shadow: 0 0 6px var(--accent-sky);
            }
            50% {
                box-shadow: 0 0 18px var(--accent-sky), 0 0 32px rgba(56, 189, 248, 0.4);
            }
        }
        nav {
            display: flex;
            align-items: center;
            gap: 4px;
            flex-wrap: wrap;
            justify-content: flex-end;
        }
        nav a {
            display: inline-block;
            padding: 7px 14px;
            border-radius: 20px;
            text-decoration: none;
            color: var(--text-secondary);
            font-size: 0.9rem;
            font-weight: 500;
            letter-spacing: 0.01em;
            transition: var(--transition-fast);
            white-space: nowrap;
            position: relative;
        }
        nav a:hover {
            color: var(--text-primary);
            background: var(--bg-glass);
        }
        nav a.current-tab {
            color: #fff;
            background: rgba(56, 189, 248, 0.12);
            font-weight: 600;
        }
        .nav-accent {
            background: var(--gradient-accent);
            color: #fff !important;
            font-weight: 600 !important;
            padding: 7px 16px !important;
            border-radius: 20px;
            box-shadow: 0 2px 12px rgba(56, 189, 248, 0.25);
            transition: var(--transition-smooth);
        }
        .nav-accent:hover {
            box-shadow: 0 4px 20px rgba(56, 189, 248, 0.4);
            transform: translateY(-1px);
        }

        /* ============ 主体容器 ============ */
        main {
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 0 24px;
        }

        .section-inner {
            padding: 50px 0;
        }
        .section-inner h2 {
            font-size: 1.7rem;
            font-weight: 700;
            letter-spacing: -0.01em;
            text-align: center;
            margin-bottom: 8px;
            color: var(--text-primary);
        }
        .section-lead {
            text-align: center;
            color: var(--text-secondary);
            max-width: 640px;
            margin: 0 auto 36px;
            font-size: 0.95rem;
            line-height: 1.6;
        }
        .section-divider {
            border: none;
            border-top: 1px solid var(--border-subtle);
            margin: 10px 0;
        }

        /* ============ 功能 Hero ============ */
        .features-hero {
            padding: 50px 0 30px;
            text-align: center;
            position: relative;
            overflow: hidden;
        }
        .features-hero::before {
            content: '';
            position: absolute;
            top: -100px;
            left: 50%;
            transform: translateX(-50%);
            width: 600px;
            height: 600px;
            background: var(--gradient-glow);
            border-radius: 50%;
            pointer-events: none;
            z-index: 0;
        }
        .hero-wrapper {
            position: relative;
            z-index: 1;
        }
        .hero-wrapper h1 {
            font-size: clamp(2rem, 4.5vw, 2.8rem);
            font-weight: 800;
            letter-spacing: -0.02em;
            line-height: 1.2;
            margin-bottom: 12px;
            background: var(--gradient-accent);
            -webkit-background-clip: text;
            background-clip: text;
            -webkit-text-fill-color: transparent;
            display: inline-block;
        }
        .hero-desc {
            max-width: 680px;
            margin: 0 auto 30px;
            color: var(--text-secondary);
            font-size: 1.02rem;
            line-height: 1.7;
        }

        /* ============ 功能矩阵卡片 ============ */
        .feature-matrix {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
            gap: 18px;
            margin-top: 10px;
        }
        .feature-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: 24px 20px;
            transition: var(--transition-smooth);
            position: relative;
            overflow: hidden;
        }
        .feature-card::after {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 3px;
            background: var(--gradient-accent);
            opacity: 0;
            transition: var(--transition-smooth);
        }
        .feature-card:hover {
            border-color: var(--border-glow);
            box-shadow: var(--shadow-card-hover);
            transform: translateY(-3px);
            background: var(--bg-card-hover);
        }
        .feature-card:hover::after {
            opacity: 1;
        }
        .feature-icon {
            font-size: 2rem;
            margin-bottom: 10px;
            display: block;
        }
        .feature-card h3 {
            font-size: 1.08rem;
            font-weight: 700;
            margin-bottom: 8px;
            letter-spacing: -0.01em;
        }
        .feature-card p {
            font-size: 0.86rem;
            color: var(--text-secondary);
            line-height: 1.55;
        }

        /* ============ 实时看板模拟 ============ */
        .dashboard-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
            gap: 16px;
            margin-top: 20px;
        }
        .dash-card {
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-md);
            padding: 18px 16px;
            text-align: center;
            transition: var(--transition-smooth);
        }
        .dash-card:hover {
            border-color: var(--accent-sky);
            box-shadow: var(--shadow-card-hover);
        }
        .dash-label {
            font-size: 0.78rem;
            text-transform: uppercase;
            letter-spacing: 0.05em;
            color: var(--text-muted);
            margin-bottom: 4px;
        }
        .dash-value {
            font-size: 2rem;
            font-weight: 800;
            background: var(--gradient-accent);
            -webkit-background-clip: text;
            background-clip: text;
            -webkit-text-fill-color: transparent;
            line-height: 1.2;
        }
        .dash-unit {
            font-size: 0.8rem;
            color: var(--text-secondary);
            margin-top: 2px;
        }

        /* ============ 操作流程 ============ */
        .flow-steps {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 16px;
            counter-reset: flow-counter;
        }
        .flow-step {
            flex: 1 1 160px;
            max-width: 220px;
            text-align: center;
            background: var(--bg-card);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-lg);
            padding: 24px 16px;
            position: relative;
            transition: var(--transition-smooth);
            counter-increment: flow-counter;
        }
        .flow-step::before {
            content: counter(flow-counter);
            position: absolute;
            top: -14px;
            left: 50%;
            transform: translateX(-50%);
            width: 32px;
            height: 32px;
            border-radius: 50%;
            background: var(--gradient-accent);
            color: #fff;
            font-weight: 700;
            font-size: 0.9rem;
            display: flex;
            align-items: center;
            justify-content: center;
            box-shadow: 0 4px 12px rgba(56, 189, 248, 0.4);
        }
        .flow-step:hover {
            border-color: var(--border-glow);
            box-shadow: var(--shadow-card-hover);
            transform: translateY(-3px);
            background: var(--bg-card-hover);
        }
        .flow-step h4 {
            margin-top: 10px;
            font-size: 0.95rem;
            font-weight: 700;
            letter-spacing: -0.01em;
        }
        .flow-step p {
            font-size: 0.8rem;
            color: var(--text-muted);
            line-height: 1.4;
            margin-top: 6px;
        }

        /* ============ 安全与备份条目 ============ */
        .safety-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
            gap: 16px;
        }
        .safety-item {
            background: var(--bg-glass);
            border: 1px solid var(--border-subtle);
            border-radius: var(--radius-md);
            padding: 18px;
            display: flex;
            align-items: flex-start;
            gap: 12px;
            transition: var(--transition-smooth);
        }
        .safety-item:hover {
            border-color: var(--accent-violet);
            background: var(--bg-card-hover);
        }
        .safety-icon {
            font-size: 1.5rem;
            flex-shrink: 0;
            width: 40px;
            text-align: center;
        }
        .safety-text h4 {
            font-size: 0.95rem;
            font-weight: 700;
            margin-bottom: 4px;
            letter-spacing: -0.01em;
        }
        .safety-text p {
            font-size: 0.8rem;
            color: var(--text-secondary);
            line-height: 1.45;
        }

        /* 页脚 */
        footer {
            border-top: 1px solid var(--border-subtle);
            background: var(--bg-secondary);
            margin-top: 40px;
        }
        .footer-wrapper {
            max-width: var(--max-width);
            margin: 0 auto;
            padding: 36px 24px 20px;
        }
        .footer-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
            gap: 24px;
            margin-bottom: 24px;
        }
        .footer-section h5 {
            font-size: 0.85rem;
            font-weight: 700;
            letter-spacing: 0.03em;
            text-transform: uppercase;
            color: var(--text-muted);
            margin-bottom: 10px;
        }
        .footer-section ul {
            list-style: none;
            padding: 0;
        }
        .footer-section ul li {
            margin-bottom: 6px;
        }
        .footer-section ul li a {
            color: var(--text-secondary);
            text-decoration: none;
            font-size: 0.84rem;
            transition: var(--transition-fast);
        }
        .footer-section ul li a:hover {
            color: var(--accent-sky);
        }
        .footer-legal {
            border-top: 1px solid var(--border-subtle);
            padding-top: 16px;
            font-size: 0.76rem;
            color: var(--text-muted);
            line-height: 1.6;
            text-align: center;
        }
        .footer-legal p {
            margin-bottom: 4px;
        }

        /* 响应式 */
        @media (max-width: 768px) {
            .header-box {
                flex-wrap: wrap;
                height: auto;
                padding: 10px 16px;
                gap: 8px;
                justify-content: center;
            }
            nav {
                justify-content: center;
                gap: 2px;
            }
            nav a {
                padding: 6px 10px;
                font-size: 0.78rem;
            }
            .section-inner h2 {
                font-size: 1.4rem;
            }
            .flow-steps {
                gap: 24px 12px;
            }
        }
        @media (max-width: 480px) {
            .feature-matrix {
                grid-template-columns: 1fr;
            }
            .dashboard-grid {
                grid-template-columns: 1fr 1fr;
            }
            .safety-grid {
                grid-template-columns: 1fr;
            }
        }