:root {
            --bg: #fafbf8;
            --surface: #ffffff;
            --text: #1a221e;
            --text-secondary: #445a4c;
            --text-muted: #6b7d6f;
            --accent: #1a6b4c;
            --accent-dark: #0f4d35;
            --accent-light: #edf7f2;
            --accent-glow: rgba(26, 107, 76, 0.10);
            --teal: #1a6b4c;
            --teal-light: #edf7f2;
            --border: #dce5de;
            --border-light: #eef3ef;
            --warm-highlight: #fdf6ed;
            --amber-accent: #c47a1a;
            --amber-light: #fef9f2;
            --shadow-sm: 0 1px 4px rgba(26, 34, 30, 0.04);
            --shadow-md: 0 6px 20px rgba(26, 34, 30, 0.05);
            --shadow-lg: 0 16px 36px rgba(26, 34, 30, 0.08);
            --shadow-xl: 0 24px 48px rgba(26, 34, 30, 0.10);
            --radius-sm: 14px;
            --radius-md: 22px;
            --radius-lg: 34px;
            --radius-xl: 46px;
            --radius-full: 999px;
            --transition: 0.20s cubic-bezier(0.4, 0, 0.2, 1);
            --font-stack: 'Inter', system-ui, -apple-system, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
        }

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

        html {
            scroll-behavior: smooth;
            -webkit-text-size-adjust: 100%;
        }

        body {
            font-family: var(--font-stack);
            background: var(--bg);
            color: var(--text);
            line-height: 1.65;
            font-size: 16px;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
            background-image:
                radial-gradient(ellipse at 12% 8%, rgba(26, 107, 76, 0.025) 0%, transparent 55%),
                radial-gradient(ellipse at 80% 55%, rgba(26, 107, 76, 0.018) 0%, transparent 48%),
                radial-gradient(ellipse at 35% 82%, rgba(196, 122, 26, 0.015) 0%, transparent 42%);
            background-attachment: fixed;
        }

        .container {
            max-width: 1220px;
            margin: 0 auto;
            padding: 0 26px;
        }

        /* ── HEADER ────────────────────── */
        header {
            background: rgba(255, 255, 255, 0.84);
            backdrop-filter: blur(18px);
            -webkit-backdrop-filter: blur(18px);
            position: sticky;
            top: 0;
            z-index: 120;
            border-bottom: 1px solid var(--border-light);
            box-shadow: var(--shadow-sm);
        }
        .nav-bar {
            display: flex;
            align-items: center;
            justify-content: space-between;
            flex-wrap: wrap;
            padding: 15px 0;
            gap: 12px;
        }
        .logo-area {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
            flex-shrink: 0;
        }
        .logo-icon {
            width: 40px;
            height: 40px;
            background: var(--accent);
            border-radius: 11px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: #fff;
            font-weight: 800;
            font-size: 1.2rem;
            letter-spacing: -0.5px;
            box-shadow: 0 4px 14px rgba(26, 107, 76, 0.28);
        }
        .logo-text {
            font-weight: 780;
            font-size: 1.3rem;
            color: var(--text);
            letter-spacing: -0.35px;
        }
        .logo-text span {
            color: var(--accent);
        }
        .nav-links {
            display: flex;
            gap: 8px;
            align-items: center;
            flex-wrap: wrap;
            font-size: 0.91rem;
        }
        .nav-links a {
            text-decoration: none;
            font-weight: 530;
            color: var(--text-secondary);
            transition: var(--transition);
            padding: 7px 15px;
            border-radius: var(--radius-full);
            white-space: nowrap;
            position: relative;
        }
        .nav-links a:hover,
        .nav-links a.active {
            color: var(--accent);
            background: var(--accent-light);
        }
        .btn-download-nav {
            background: var(--accent) !important;
            color: #fff !important;
            padding: 9px 21px !important;
            border-radius: var(--radius-full) !important;
            font-weight: 600 !important;
            box-shadow: 0 3px 12px rgba(26, 107, 76, 0.24);
            transition: var(--transition) !important;
        }
        .btn-download-nav:hover {
            background: var(--accent-dark) !important;
            transform: translateY(-2px);
            box-shadow: 0 6px 18px rgba(26, 107, 76, 0.32);
        }

        /* ── 页头 ─────────────── */
        .page-hero {
            padding: 54px 0 36px;
            text-align: center;
        }
        .page-hero h1 {
            font-size: clamp(2rem, 4vw, 2.9rem);
            font-weight: 850;
            letter-spacing: -0.5px;
            margin-bottom: 16px;
            line-height: 1.2;
        }
        .page-hero h1 .accent {
            color: var(--accent);
            position: relative;
            display: inline-block;
        }
        .page-hero h1 .accent::after {
            content: '';
            position: absolute;
            bottom: 2px;
            left: 0;
            width: 100%;
            height: 7px;
            background: rgba(26, 107, 76, 0.16);
            border-radius: 3px;
            z-index: -1;
        }
        .page-hero .subtitle {
            font-size: 1.05rem;
            color: var(--text-secondary);
            max-width: 680px;
            margin: 0 auto;
            line-height: 1.6;
        }

        /* ── 架构层次可视化 ────── */
        .architecture-visual {
            display: flex;
            flex-direction: column;
            align-items: center;
            gap: 18px;
            margin: 44px 0 56px;
        }
        .arch-layer {
            background: var(--surface);
            border: 1px solid var(--border-light);
            border-radius: var(--radius-md);
            padding: 24px 32px;
            box-shadow: var(--shadow-sm);
            width: 100%;
            max-width: 700px;
            display: flex;
            align-items: center;
            gap: 20px;
            transition: var(--transition);
            position: relative;
        }
        .arch-layer:hover {
            border-color: var(--accent);
            box-shadow: var(--shadow-md);
            transform: translateX(4px);
        }
        .arch-layer .layer-icon {
            font-size: 2.4rem;
            width: 60px;
            height: 60px;
            background: var(--accent-light);
            border-radius: 20px;
            display: flex;
            align-items: center;
            justify-content: center;
            flex-shrink: 0;
            color: var(--accent);
        }
        .layer-content h3 {
            font-size: 1.25rem;
            font-weight: 700;
            margin-bottom: 6px;
            letter-spacing: -0.2px;
        }
        .layer-content p {
            font-size: 0.93rem;
            color: var(--text-secondary);
            line-height: 1.55;
        }
        .arch-connector {
            width: 2px;
            height: 14px;
            background: var(--border);
            position: relative;
        }
        .arch-connector::after {
            content: '';
            position: absolute;
            bottom: -4px;
            left: -3px;
            width: 8px;
            height: 8px;
            background: var(--accent);
            border-radius: 50%;
        }

        /* ── 详细模块卡片 ──────── */
       .module-grid {
    display: flex;
    flex-direction: column;
    gap: 36px;
    margin: 48px auto;          /* 上下间距，左右自动居中 */
    max-width: 860px;           /* 与下载卡片、教程卡片保持统一宽度 */
    width: 100%;
}
        .module-card {
            background: var(--surface);
            border-radius: var(--radius-lg);
            border: 1px solid var(--border-light);
            padding: 0;
            box-shadow: var(--shadow-sm);
            overflow: hidden;
            transition: var(--transition);
        }
        .module-card:hover {
            box-shadow: var(--shadow-md);
        }
        .module-header {
            background: #f7faf5;
            padding: 22px 30px;
            display: flex;
            align-items: center;
            gap: 18px;
            border-bottom: 1px solid var(--border-light);
        }
        .module-header .mod-icon {
            font-size: 2rem;
            width: 52px;
            height: 52px;
            background: var(--accent-light);
            border-radius: 16px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--accent);
        }
        .module-header h2 {
            font-size: 1.45rem;
            font-weight: 750;
            letter-spacing: -0.3px;
        }
        .module-body {
            padding: 26px 30px;
            font-size: 0.96rem;
            color: var(--text-secondary);
            line-height: 1.7;
        }
        .module-body p {
            margin-bottom: 14px;
        }
        .module-body ul {
            padding-left: 20px;
            margin: 10px 0;
        }
        .module-body li {
            margin-bottom: 8px;
        }

        /* 协议表格 */
        .proto-table {
            width: 100%;
            border-collapse: collapse;
            margin: 18px 0;
            font-size: 0.92rem;
        }
        .proto-table th {
            background: #f7faf5;
            padding: 12px 16px;
            text-align: left;
            font-weight: 680;
            color: var(--text);
            border-bottom: 2px solid var(--border);
        }
        .proto-table td {
            padding: 11px 16px;
            border-bottom: 1px solid var(--border-light);
            color: var(--text-secondary);
        }
        .proto-table tr:hover td {
            background: #f9fcf6;
        }

        /* 折叠细节 */
        .tech-details {
            margin-top: 18px;
        }
        .tech-details summary {
            font-weight: 650;
            cursor: pointer;
            color: var(--accent);
            padding: 8px 0;
            list-style: none;
            display: inline-flex;
            align-items: center;
            gap: 6px;
        }
        .tech-details summary::-webkit-details-marker {
            display: none;
        }
        .tech-details .detail-content {
            background: var(--teal-light);
            border-radius: 14px;
            padding: 16px 20px;
            margin-top: 10px;
            font-size: 0.91rem;
            color: #1a3d2a;
            border-left: 4px solid var(--teal);
            line-height: 1.6;
        }

        /* 内链引导条 */
        .related-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 14px;
    margin: 40px auto 20px;     /* 上下间距，左右自动居中 */
    max-width: 700px;           /* 略窄一些，更适合按钮排列 */
    width: 100%;
}
        .related-links a {
            background: var(--surface);
            border: 1px solid var(--border);
            padding: 11px 26px;
            border-radius: 40px;
            text-decoration: none;
            color: var(--text);
            font-weight: 530;
            transition: var(--transition);
        }
        .related-links a:hover {
            border-color: var(--accent);
            color: var(--accent);
            background: var(--accent-light);
        }

        /* FOOTER */
        .footer {
            background: #172418;
            color: #b8c9bb;
            padding: 40px 0 22px;
            border-radius: var(--radius-lg) var(--radius-lg) 0 0;
            margin-top: 48px;
        }
        .footer-grid {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            gap: 30px;
        }
        .footer-col h4 {
            color: #fff;
            margin-bottom: 11px;
            font-size: 0.93rem;
            letter-spacing: -0.12px;
        }
        .footer-col a {
            color: #b8c9bb;
            text-decoration: none;
            display: block;
            margin-bottom: 6px;
            font-size: 0.85rem;
            transition: var(--transition);
        }
        .footer-col a:hover {
            color: #fff;
            text-decoration: underline;
            text-underline-offset: 3px;
        }
        .footer-copyright {
            text-align: center;
            padding-top: 28px;
            font-size: 0.8rem;
            border-top: 1px solid #2d402f;
            margin-top: 22px;
            color: #8a9a8c;
        }
        .footer-disclaimer {
            text-align: center;
            font-size: 0.74rem;
            color: #6d7e6f;
            margin-top: 10px;
            line-height: 1.5;
        }

        @media (max-width: 900px) {
            .nav-bar {
                flex-direction: column;
                align-items: stretch;
            }
            .nav-links {
                gap: 5px;
                font-size: 0.82rem;
            }
            .arch-layer {
                flex-direction: column;
                text-align: center;
            }
        }
        @media (max-width: 480px) {
            .container {
                padding: 0 14px;
            }
        }