:root {
            --brand-dark: #0f172a;
            --brand-blue: #3b82f6;
            --brand-blue-hover: #2563eb;
            --text-main: #334155;
            --text-title: #1e293b;
            --bg-light: #ffffff;
            --bg-accent: #f8fafc;
            --border-line: #cbd5e1;
        }
        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            color: var(--text-main);
            line-height: 1.75;
            background-color: var(--bg-light);
        }
        header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 1.25rem 6%;
            background: var(--brand-dark);
            color: #ffffff;
            position: sticky;
            top: 0;
            z-index: 2000;
            box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
        }
        .logo {
            display: flex;
            align-items: center;
            font-size: 1.4rem;
            font-weight: 700;
            color: #ffffff;
            text-decoration: none;
        }
        .logo img {
            width: auto;
            height: 38px;
            margin-right: 12px;
            display: block;
        }
        .nav-box {
            display: flex;
            align-items: center;
        }
        nav a {
            margin-left: 1.75rem;
            text-decoration: none;
            color: #cbd5e1;
            font-size: 0.95rem;
            transition: color 0.2s;
        }
        nav a:hover {
            color: var(--brand-blue);
        }
        .github-btn {
            display: inline-flex;
            align-items: center;
            background-color: var(--brand-blue);
            color: #ffffff;
            padding: 0.55rem 1.1rem;
            border-radius: 6px;
            font-size: 0.9rem;
            text-decoration: none;
            margin-left: 2rem;
            transition: background-color 0.2s;
            font-weight: 500;
        }
        .github-btn:hover {
            background-color: var(--brand-blue-hover);
        }
        .github-btn svg {
            width: 16px;
            height: 16px;
            margin-right: 6px;
            fill: currentColor;
        }
        .main-wrapper {
            max-width: 1260px;
            margin: 0 auto;
            padding: 0 6%;
        }
        .hero-block {
            display: flex;
            flex-direction: column;
            align-items: center;
            text-align: center;
            padding: 5rem 0 3.5rem 0;
        }
        .hero-block h1 {
            font-size: 2.8rem;
            color: var(--brand-dark);
            line-height: 1.25;
            max-width: 900px;
            margin-bottom: 1.5rem;
        }
        .hero-block p {
            font-size: 1.15rem;
            color: #64748b;
            max-width: 750px;
            margin-bottom: 2.5rem;
        }
        .multimedia-slot {
            width: 100%;
            max-width: 1000px;
            height: 550px;
            background-color: #f1f5f9;
            border: 2px dashed #94a3b8;
            border-radius: 12px;
            display: flex;
            align-items: center;
            justify-content: center;
            position: relative;
        }
        .multimedia-slot img {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            object-fit: cover;
            opacity: 1;
        }
        .multimedia-slot::after {
            content: "首页核心架构与分流原理演示主图 [1200x700 预留位]";
            color: #64748b;
            font-size: 0.95rem;
        }
        .section-title {
            font-size: 2.2rem;
            color: var(--brand-dark);
            text-align: center;
            margin-bottom: 1rem;
        }
        .section-subtitle {
            text-align: center;
            max-width: 750px;
            margin: 0 auto 3.5rem auto;
            color: #64748b;
            font-size: 1rem;
        }
        .download-panel {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
            gap: 1.75rem;
            margin-bottom: 2rem;
        }
        .download-item {
            background: #ffffff;
            border: 1px solid var(--border-line);
            border-top: 4px solid var(--brand-dark);
            border-radius: 8px;
            padding: 2.5rem 1.5rem;
            text-align: center;
            display: flex;
            flex-direction: column;
            justify-content: space-between;
            transition: transform 0.2s, box-shadow 0.2s;
        }
        .download-item:hover {
            transform: translateY(-4px);
            box-shadow: 0 10px 15px -3px rgba(0,0,0,0.05);
        }
        .download-item h3 {
            font-size: 1.5rem;
            color: var(--brand-dark);
            margin-bottom: 0.5rem;
        }
        .download-item .platform-spec {
            font-size: 0.85rem;
            color: #64748b;
            margin-bottom: 2rem;
        }
        .actions-area {
            display: flex;
            flex-direction: column;
            gap: 0.8rem;
        }
        .action-main-link {
            display: block;
            background-color: var(--brand-dark);
            color: #ffffff;
            padding: 0.8rem 1rem;
            border-radius: 6px;
            text-decoration: none;
            font-weight: 500;
            font-size: 0.95rem;
            transition: background-color 0.2s;
        }
        .action-main-link:hover {
            background-color: var(--brand-blue-hover);
        }
        .action-sub-link {
            display: block;
            background-color: #ffffff;
            color: #475569;
            padding: 0.7rem 1rem;
            border-radius: 6px;
            text-decoration: none;
            font-size: 0.85rem;
            font-weight: 500;
            border: 1px solid var(--border-line);
            transition: all 0.2s;
        }
        .action-sub-link:hover {
            background-color: #f1f5f9;
            color: var(--brand-dark);
            border-color: #94a3b8;
        }
        .split-layout {
            display: grid;
            grid-template-columns: 5fr 7fr;
            gap: 4rem;
            align-items: start;
        }
        .asymmetric-card {
            background: #0f172a;
            color: #f8fafc;
            padding: 3rem;
            border-radius: 12px;
        }
        .asymmetric-card h3 {
            font-size: 1.6rem;
            margin-bottom: 1.25rem;
            color: #ffffff;
        }
        .asymmetric-card p {
            color: #94a3b8;
            font-size: 1rem;
            margin-bottom: 1.5rem;
        }
        .text-nodes h3 {
            font-size: 1.4rem;
            color: var(--brand-dark);
            margin-top: 2rem;
            margin-bottom: 0.75rem;
        }
        .text-nodes p {
            color: var(--text-main);
            margin-bottom: 1.5rem;
        }
        .feature-flow {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
            gap: 2rem;
        }
        .flow-node {
            background: var(--bg-accent);
            border-left: 4px solid var(--brand-blue);
            padding: 2rem;
            border-radius: 0 8px 8px 0;
        }
        .flow-node h3 {
            font-size: 1.3rem;
            color: var(--brand-dark);
            margin-bottom: 0.75rem;
        }
        .flow-node p {
            font-size: 0.95rem;
        }
        .lexicon-box {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 3rem 4rem;
        }
        .lexicon-item h3 {
            font-size: 1.25rem;
            color: var(--brand-dark);
            margin-bottom: 0.75rem;
            border-bottom: 2px solid var(--brand-blue);
            display: inline-block;
            padding-bottom: 2px;
        }
        .lexicon-item p {
            font-size: 0.95rem;
            color: #475569;
        }
        .lexicon-item ul {
            list-style-type: square;
            padding-left: 1.25rem;
            margin-top: 0.5rem;
            color: #475569;
            font-size: 0.95rem;
        }
        .lexicon-item ul li {
            margin-bottom: 0.4rem;
        }
        section {
            padding: 5rem 0;
        }
        .bg-section {
            background-color: var(--bg-accent);
            border-top: 1px solid #e2e8f0;
            border-bottom: 1px solid #e2e8f0;
        }
        footer {
            background: #020617;
            color: #94a3b8;
            padding: 4rem 6%;
            text-align: center;
            font-size: 0.9rem;
            border-top: 1px solid #1e293b;
        }
        @media (max-width: 960px) {
            header {
                flex-direction: column;
                gap: 1.25rem;
                padding: 1.5rem 5%;
            }
            .nav-box {
                flex-direction: column;
                gap: 1.25rem;
                width: 100%;
            }
            nav {
                display: flex;
                justify-content: center;
                flex-wrap: wrap;
                gap: 0.5rem;
            }
            nav a {
                margin: 0 0.75rem;
            }
            .github-btn {
                margin-left: 0;
            }
            .split-layout {
                grid-template-columns: 1fr;
                gap: 2.5rem;
            }
            .lexicon-box {
                grid-template-columns: 1fr;
                gap: 2rem;
            }
        }