:root {
            --bg-deep: #080d16;
            --bg-card: #111827;
            --bg-card-hover: #161e2d;
            --bg-surface: #0f1726;
            --text-primary: #e8ecf2;
            --text-secondary: #b0bdd0;
            --text-muted: #6f7d94;
            --accent-cyan: #00d4aa;
            --accent-blue: #3b82f6;
            --accent-purple: #8b5cf6;
            --accent-amber: #f59e0b;
            --accent-rose: #f43f5e;
            --border-subtle: #1e293b;
            --border-glow: #1e3a5f;
            --glow-cyan: rgba(0, 212, 170, 0.15);
            --glow-blue: rgba(59, 130, 246, 0.12);
            --glow-purple: rgba(139, 92, 246, 0.12);
            --radius-sm: 10px;
            --radius-md: 18px;
            --radius-lg: 28px;
            --radius-xl: 36px;
            --transition-fast: 0.18s ease;
            --transition-smooth: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
            --font-mono: 'SF Mono', 'Cascadia Code', 'Consolas', 'Menlo', monospace;
        }

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

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

        body {
            font-family: system-ui, -apple-system, 'Segoe UI', 'Helvetica Neue', Helvetica, 'Noto Sans SC', sans-serif;
            background-color: var(--bg-deep);
            color: var(--text-primary);
            line-height: 1.6;
            letter-spacing: 0.01em;
            overflow-x: hidden;
        }

        /* 全局光晕背景 */
        body::before {
            content: '';
            position: fixed;
            top: -30vh;
            left: -20vw;
            width: 70vw;
            height: 70vh;
            background: radial-gradient(ellipse at center, rgba(0, 180, 140, 0.06) 0%, transparent 70%);
            pointer-events: none;
            z-index: 0;
        }
        body::after {
            content: '';
            position: fixed;
            bottom: -20vh;
            right: -15vw;
            width: 60vw;
            height: 60vh;
            background: radial-gradient(ellipse at center, rgba(100, 80, 240, 0.05) 0%, transparent 70%);
            pointer-events: none;
            z-index: 0;
        }

        .container {
            max-width: 1240px;
            margin: 0 auto;
            padding: 0 24px;
            position: relative;
            z-index: 1;
        }

        /* ========== HEADER ========== */
        .site-header {
            position: sticky;
            top: 0;
            z-index: 100;
            background: rgba(8, 13, 22, 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-inner {
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            padding: 14px 0;
            gap: 16px;
        }

        .logo-area {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
        }
        .logo-icon {
            width: 42px;
            height: 42px;
            background: linear-gradient(135deg, #00c49a, #0ea5e9);
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 21px;
            font-weight: 800;
            color: #fff;
            box-shadow: 0 0 22px rgba(0, 200, 160, 0.25);
            letter-spacing: -0.5px;
        }
        .logo-text {
            font-size: 1.45rem;
            font-weight: 700;
            letter-spacing: -0.3px;
            background: linear-gradient(135deg, #e8ecf2, #a0c4f0);
            background-clip: text;
            -webkit-background-clip: text;
            color: transparent;
        }
        .logo-sub {
            font-size: 0.7rem;
            color: var(--text-muted);
            display: block;
            letter-spacing: 0.04em;
            font-weight: 400;
            margin-top: -2px;
        }

        .nav-links {
            display: flex;
            gap: 26px;
            align-items: center;
            flex-wrap: wrap;
        }
        .nav-links a {
            text-decoration: none;
            font-weight: 500;
            color: var(--text-secondary);
            transition: color var(--transition-fast);
            font-size: 0.95rem;
            position: relative;
            padding: 4px 0;
        }
        .nav-links a::after {
            content: '';
            position: absolute;
            bottom: -2px;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--accent-cyan);
            border-radius: 2px;
            transition: width var(--transition-smooth);
        }
        .nav-links a:hover,
        .nav-links a.active {
            color: #fff;
        }
        .nav-links a:hover::after,
        .nav-links a.active::after {
            width: 100%;
        }
        .btn-nav-dl {
            border: 1px solid var(--accent-cyan);
            padding: 7px 18px;
            border-radius: 40px;
            color: var(--accent-cyan) !important;
            font-weight: 600;
            transition: all var(--transition-smooth);
            font-size: 0.9rem;
        }
        .btn-nav-dl:hover {
            background: var(--accent-cyan);
            color: #080d16 !important;
            box-shadow: 0 0 20px var(--glow-cyan);
        }
        .btn-nav-dl::after {
            display: none !important;
        }

        /* ========== HERO ========== */
        .hero {
            padding: 70px 0 56px;
            position: relative;
        }
        .hero-grid {
            display: flex;
            flex-wrap: wrap;
            align-items: center;
            justify-content: space-between;
            gap: 44px;
        }
        .hero-content {
            flex: 1;
            min-width: 290px;
        }
        .hero-eyebrow {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            background: rgba(0, 210, 160, 0.08);
            border: 1px solid rgba(0, 210, 160, 0.22);
            color: #00d4aa;
            font-size: 0.82rem;
            padding: 5px 14px;
            border-radius: 32px;
            margin-bottom: 22px;
            font-weight: 500;
            letter-spacing: 0.03em;
        }
        .hero-eyebrow .dot {
            width: 7px;
            height: 7px;
            background: #00d4aa;
            border-radius: 50%;
            animation: pulse-dot 1.8s infinite;
        }
        @keyframes pulse-dot {
            0%,
            100% {
                box-shadow: 0 0 0 0 rgba(0, 212, 170, 0.7);
            }
            50% {
                box-shadow: 0 0 0 10px rgba(0, 212, 170, 0);
            }
        }
        .hero h1 {
            font-size: clamp(2.2rem, 4.5vw, 3.4rem);
            font-weight: 800;
            line-height: 1.18;
            letter-spacing: -0.025em;
            margin-bottom: 18px;
            color: #f0f4f8;
        }
        .hero-highlight {
            background: linear-gradient(125deg, #00d4aa 0%, #3b82f6 50%, #8b5cf6 100%);
            background-clip: text;
            -webkit-background-clip: text;
            color: transparent;
            animation: shimmer-text 4s ease-in-out infinite;
            background-size: 200% 100%;
        }
        @keyframes shimmer-text {
            0%,
            100% {
                background-position: 0% 50%;
            }
            50% {
                background-position: 100% 50%;
            }
        }
        .hero p {
            font-size: 1.12rem;
            color: var(--text-secondary);
            margin-bottom: 30px;
            max-width: 580px;
            line-height: 1.7;
        }
        .hero-buttons {
            display: flex;
            flex-wrap: wrap;
            gap: 14px;
        }
        .btn-primary {
            background: linear-gradient(135deg, #00c49a, #0ea5e9);
            color: #080d16;
            border: none;
            padding: 13px 30px;
            border-radius: 40px;
            font-weight: 700;
            font-size: 1rem;
            cursor: pointer;
            transition: all var(--transition-smooth);
            text-decoration: none;
            display: inline-flex;
            align-items: center;
            gap: 7px;
            letter-spacing: 0.02em;
            box-shadow: 0 4px 24px rgba(0, 200, 160, 0.3);
        }
        .btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 36px rgba(0, 200, 160, 0.45);
            filter: brightness(1.08);
        }
        .btn-secondary {
            background: transparent;
            border: 1px solid var(--border-subtle);
            padding: 13px 28px;
            border-radius: 40px;
            font-weight: 600;
            text-decoration: none;
            color: #e8ecf2;
            transition: all var(--transition-smooth);
            display: inline-flex;
            align-items: center;
            gap: 7px;
        }
        .btn-secondary:hover {
            background: rgba(255, 255, 255, 0.04);
            border-color: #4b5563;
        }
        .hero-visual {
            flex: 1;
            min-width: 260px;
            background: var(--bg-surface);
            border-radius: var(--radius-xl);
            padding: 28px 24px;
            border: 1px solid var(--border-subtle);
            position: relative;
            overflow: hidden;
        }
        .hero-visual::before {
            content: '';
            position: absolute;
            inset: -1px;
            border-radius: var(--radius-xl);
            padding: 1px;
            background: linear-gradient(145deg, rgba(0, 212, 170, 0.3), transparent 60%, rgba(100, 130, 246, 0.2));
            -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
            -webkit-mask-composite: xor;
            mask-composite: exclude;
            pointer-events: none;
        }
        .hero-visual-inner {
            display: flex;
            flex-direction: column;
            gap: 14px;
        }
        .vis-row {
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 12px 16px;
            background: var(--bg-card);
            border-radius: var(--radius-sm);
            border: 1px solid transparent;
            transition: var(--transition-fast);
        }
        .vis-row:hover {
            border-color: var(--border-glow);
        }
        .vis-dot {
            width: 10px;
            height: 10px;
            border-radius: 50%;
            flex-shrink: 0;
        }
        .vis-dot.green {
            background: #10b981;
            box-shadow: 0 0 10px #10b98188;
        }
        .vis-dot.blue {
            background: #3b82f6;
            box-shadow: 0 0 10px #3b82f688;
        }
        .vis-dot.purple {
            background: #8b5cf6;
            box-shadow: 0 0 10px #8b5cf688;
        }
        .vis-label {
            font-size: 0.88rem;
            color: #c8d2e0;
            font-weight: 500;
        }
        .vis-tag {
            margin-left: auto;
            font-size: 0.72rem;
            padding: 4px 10px;
            border-radius: 20px;
            font-weight: 600;
            letter-spacing: 0.03em;
            background: rgba(255, 255, 255, 0.04);
            color: var(--text-muted);
            border: 1px solid var(--border-subtle);
        }
        .vis-speed {
            font-family: var(--font-mono);
            font-size: 0.78rem;
            color: #00d4aa;
        }

        /* ========== 创意问题导向入口 ========== */
        .problem-entrance {
            padding: 56px 0 64px;
        }
        .section-label {
            text-align: center;
            font-size: 0.8rem;
            text-transform: uppercase;
            letter-spacing: 0.12em;
            color: var(--accent-cyan);
            margin-bottom: 8px;
            font-weight: 600;
        }
        .section-title {
            text-align: center;
            font-size: clamp(1.8rem, 3.5vw, 2.4rem);
            font-weight: 700;
            margin-bottom: 10px;
            letter-spacing: -0.02em;
            color: #f0f4f8;
        }
        .section-desc {
            text-align: center;
            color: var(--text-secondary);
            max-width: 680px;
            margin: 0 auto 48px auto;
            font-size: 1.02rem;
            line-height: 1.65;
        }
        .problem-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
            gap: 20px;
        }
        .problem-card {
            background: var(--bg-card);
            border-radius: var(--radius-md);
            padding: 26px 22px;
            border: 1px solid var(--border-subtle);
            cursor: pointer;
            transition: all var(--transition-smooth);
            text-decoration: none;
            color: inherit;
            display: flex;
            flex-direction: column;
            gap: 10px;
            position: relative;
            overflow: hidden;
        }
        .problem-card:hover {
            border-color: var(--border-glow);
            transform: translateY(-3px);
            box-shadow: 0 18px 40px -14px rgba(0, 0, 0, 0.5);
        }
        .problem-card .card-emoji {
            font-size: 2.6rem;
        }
        .problem-card h3 {
            font-size: 1.08rem;
            font-weight: 700;
            color: #f0f4f8;
            line-height: 1.3;
        }
        .problem-card p {
            font-size: 0.85rem;
            color: var(--text-muted);
            line-height: 1.5;
        }
        .problem-card .card-link {
            font-size: 0.82rem;
            font-weight: 600;
            color: var(--accent-cyan);
            display: inline-flex;
            align-items: center;
            gap: 4px;
            margin-top: auto;
        }
        .problem-card.card-gaming {
            border-top: 3px solid #f43f5e;
        }
        .problem-card.card-streaming {
            border-top: 3px solid #f59e0b;
        }
        .problem-card.card-office {
            border-top: 3px solid #3b82f6;
        }
        .problem-card.card-ai {
            border-top: 3px solid #8b5cf6;
        }
        .problem-card::after {
            content: '';
            position: absolute;
            top: -30px;
            right: -30px;
            width: 80px;
            height: 80px;
            border-radius: 50%;
            opacity: 0.04;
            pointer-events: none;
            transition: opacity var(--transition-smooth);
        }
        .problem-card:hover::after {
            opacity: 0.1;
        }
        .problem-card.card-gaming::after {
            background: #f43f5e;
        }
        .problem-card.card-streaming::after {
            background: #f59e0b;
        }
        .problem-card.card-office::after {
            background: #3b82f6;
        }
        .problem-card.card-ai::after {
            background: #8b5cf6;
        }

        /* ========== 三层网络系统 ========== */
        .three-layer {
            padding: 60px 0 70px;
            background: var(--bg-surface);
            border-top: 1px solid var(--border-subtle);
            border-bottom: 1px solid var(--border-subtle);
        }
        .layer-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 28px;
            margin-top: 40px;
        }
        .layer-card {
            background: var(--bg-card);
            border-radius: var(--radius-lg);
            padding: 30px 24px;
            border: 1px solid var(--border-subtle);
            transition: all var(--transition-smooth);
            position: relative;
        }
        .layer-card:hover {
            border-color: var(--border-glow);
            box-shadow: 0 12px 32px -10px rgba(0, 0, 0, 0.4);
        }
        .layer-num {
            font-family: var(--font-mono);
            font-size: 3.5rem;
            font-weight: 900;
            letter-spacing: -0.04em;
            line-height: 1;
            margin-bottom: 8px;
        }
        .layer-card.card-node .layer-num {
            color: #10b981;
            opacity: 0.7;
        }
        .layer-card.card-rule .layer-num {
            color: #3b82f6;
            opacity: 0.7;
        }
        .layer-card.card-client .layer-num {
            color: #8b5cf6;
            opacity: 0.7;
        }
        .layer-card h3 {
            font-size: 1.3rem;
            font-weight: 700;
            margin-bottom: 6px;
            color: #f0f4f8;
        }
        .layer-card .layer-subtitle {
            font-size: 0.8rem;
            color: var(--text-muted);
            letter-spacing: 0.04em;
            margin-bottom: 14px;
        }
        .layer-card p {
            color: var(--text-secondary);
            font-size: 0.93rem;
            line-height: 1.6;
        }
        .layer-tags {
            display: flex;
            flex-wrap: wrap;
            gap: 8px;
            margin-top: 14px;
        }
        .layer-tag {
            font-size: 0.72rem;
            padding: 4px 12px;
            border-radius: 20px;
            font-weight: 500;
            border: 1px solid var(--border-subtle);
            color: var(--text-secondary);
            letter-spacing: 0.02em;
        }

        /* ========== 功能亮点 ========== */
        .features {
            padding: 72px 0;
        }
        .features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
            gap: 24px;
            margin-top: 40px;
        }
        .feature-card {
            background: var(--bg-card);
            border-radius: var(--radius-md);
            padding: 26px 22px;
            border: 1px solid var(--border-subtle);
            transition: all var(--transition-smooth);
        }
        .feature-card:hover {
            border-color: var(--border-glow);
            box-shadow: 0 8px 28px -8px rgba(0, 0, 0, 0.5);
            transform: translateY(-2px);
        }
        .feature-icon {
            font-size: 2.2rem;
            margin-bottom: 14px;
        }
        .feature-card h3 {
            font-size: 1.15rem;
            font-weight: 600;
            margin-bottom: 8px;
            color: #f0f4f8;
        }
        .feature-card p {
            color: var(--text-secondary);
            font-size: 0.9rem;
            line-height: 1.55;
        }

        /* ========== CTA 横幅 ========== */
        .cta-strip {
            padding: 56px 0;
            text-align: center;
        }
        .cta-inner {
            background: linear-gradient(135deg, #0f1a2c, #111d30);
            border-radius: var(--radius-xl);
            padding: 48px 32px;
            border: 1px solid var(--border-subtle);
            position: relative;
            overflow: hidden;
        }
        .cta-inner::before {
            content: '';
            position: absolute;
            top: -40px;
            right: -40px;
            width: 160px;
            height: 160px;
            background: radial-gradient(circle, rgba(0, 212, 170, 0.18) 0%, transparent 70%);
            pointer-events: none;
        }
        .cta-inner h2 {
            font-size: clamp(1.6rem, 3vw, 2.2rem);
            font-weight: 700;
            color: #f0f4f8;
            margin-bottom: 12px;
            position: relative;
            z-index: 1;
        }
        .cta-inner p {
            color: var(--text-secondary);
            max-width: 560px;
            margin: 0 auto 24px;
            position: relative;
            z-index: 1;
            font-size: 1rem;
        }
        .cta-inner .btn-primary {
            position: relative;
            z-index: 1;
        }

        /* ========== 内链导航区 ========== */
        .quick-links-section {
            padding: 32px 0 56px;
        }
        .quick-links-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
            gap: 16px;
            margin-top: 32px;
        }
        .quick-link-card {
            background: var(--bg-card);
            border-radius: var(--radius-sm);
            padding: 18px 16px;
            border: 1px solid var(--border-subtle);
            text-decoration: none;
            color: #e8ecf2;
            transition: all var(--transition-smooth);
            display: flex;
            align-items: center;
            gap: 10px;
            font-weight: 500;
            font-size: 0.93rem;
        }
        .quick-link-card:hover {
            border-color: var(--accent-cyan);
            box-shadow: 0 0 18px var(--glow-cyan);
            color: #fff;
        }
        .quick-link-card .ql-icon {
            font-size: 1.3rem;
            flex-shrink: 0;
        }

        /* ========== FOOTER ========== */
        .site-footer {
            background: var(--bg-surface);
            border-top: 1px solid var(--border-subtle);
            padding: 48px 0 28px;
            color: var(--text-muted);
            font-size: 0.88rem;
        }
        .footer-links {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            gap: 32px;
            margin-bottom: 36px;
        }
        .footer-col {
            flex: 1;
            min-width: 140px;
        }
        .footer-col h4 {
            font-weight: 600;
            margin-bottom: 14px;
            color: #e8ecf2;
            font-size: 0.95rem;
        }
        .footer-col a {
            display: block;
            color: var(--text-muted);
            text-decoration: none;
            margin-bottom: 10px;
            font-size: 0.85rem;
            transition: color var(--transition-fast);
        }
        .footer-col a:hover {
            color: var(--accent-cyan);
        }
        .copyright {
            text-align: center;
            font-size: 0.78rem;
            padding-top: 20px;
            border-top: 1px solid var(--border-subtle);
            color: var(--text-muted);
        }
        .copyright a {
            color: var(--accent-cyan);
            text-decoration: none;
        }

        /* ========== 响应式 ========== */
        @media (max-width: 768px) {
            .header-inner {
                flex-direction: column;
                gap: 12px;
            }
            .nav-links {
                gap: 16px;
                justify-content: center;
            }
            .hero-grid {
                flex-direction: column-reverse;
                gap: 28px;
            }
            .hero h1 {
                font-size: 1.9rem;
            }
            .problem-grid {
                grid-template-columns: 1fr 1fr;
            }
            .layer-grid {
                grid-template-columns: 1fr;
            }
            .features-grid {
                grid-template-columns: 1fr;
            }
            .quick-links-grid {
                grid-template-columns: 1fr 1fr;
            }
            .hero-visual {
                padding: 18px 14px;
            }
            .vis-row {
                padding: 10px 12px;
                gap: 8px;
            }
        }
        @media (max-width: 480px) {
            .problem-grid {
                grid-template-columns: 1fr;
            }
            .quick-links-grid {
                grid-template-columns: 1fr;
            }
            .hero-buttons {
                flex-direction: column;
                align-items: stretch;
            }
            .btn-primary,
            .btn-secondary {
                text-align: center;
                justify-content: center;
            }
        }