:root {
            --primary: #4f46e5;
            --primary-light: #6366f1;
            --primary-dark: #3730a3;
            --accent: #06b6d4;
            --accent-green: #10b981;
            --text: #1e293b;
            --text-secondary: #475569;
            --text-muted: #64748b;
            --bg: #ffffff;
            --bg-soft: #f8fafc;
            --bg-card: #f1f5f9;
            --border: #e2e8f0;
            --border-light: #f1f5f9;
            --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.06);
            --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.07), 0 1px 4px rgba(0, 0, 0, 0.05);
            --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.10), 0 4px 12px rgba(0, 0, 0, 0.05);
            --radius-sm: 8px;
            --radius: 14px;
            --radius-lg: 20px;
            --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
            --font-mono: 'SF Mono', 'Fira Code', 'Cascadia Code', 'Consolas', monospace;
        }
        *,
        *::before,
        *::after {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }
        html {
            scroll-behavior: smooth;
            -webkit-text-size-adjust: 100%;
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans SC", sans-serif;
            color: var(--text);
            background-color: var(--bg);
            line-height: 1.75;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
            background-image:
                radial-gradient(ellipse at 15% 5%, rgba(99, 102, 241, 0.03) 0%, transparent 55%),
                radial-gradient(ellipse at 85% 90%, rgba(6, 182, 212, 0.03) 0%, transparent 55%);
            background-attachment: fixed;
        }
        /* 导航栏 (与首页完全一致) */
        header {
            background: rgba(255, 255, 255, 0.85);
            backdrop-filter: blur(16px);
            -webkit-backdrop-filter: blur(16px);
            border-bottom: 1px solid var(--border);
            position: sticky;
            top: 0;
            z-index: 100;
            transition: box-shadow var(--transition);
        }
        header.scrolled {
            box-shadow: var(--shadow-md);
        }
        .nav-container {
            max-width: 1240px;
            margin: 0 auto;
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 14px 24px;
            gap: 16px;
        }
        .logo {
            font-size: 1.25rem;
            font-weight: 700;
            color: var(--primary);
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 10px;
            letter-spacing: -0.02em;
            white-space: nowrap;
            transition: opacity var(--transition);
        }
        .logo:hover {
            opacity: 0.82;
        }
        .logo img {
            height: 34px;
            width: auto;
            display: block;
            flex-shrink: 0;
        }
        .logo-dot {
            display: inline-block;
            width: 7px;
            height: 7px;
            border-radius: 50%;
            background: var(--accent);
            margin-left: 2px;
            animation: pulse-dot 2.4s ease-in-out infinite;
        }
        @keyframes pulse-dot {
            0%, 100% { opacity: 0.4; transform: scale(1); }
            50% { opacity: 1; transform: scale(1.6); }
        }
        .nav-links {
            display: flex;
            list-style: none;
            gap: 6px;
            align-items: center;
            flex-wrap: wrap;
        }
        .nav-links a {
            text-decoration: none;
            color: var(--text-secondary);
            font-weight: 500;
            font-size: 0.95rem;
            padding: 8px 16px;
            border-radius: 20px;
            transition: all var(--transition);
            white-space: nowrap;
            position: relative;
        }
        .nav-links a:hover {
            color: var(--primary);
            background: rgba(79, 70, 229, 0.06);
        }
        .nav-links a.active {
            color: var(--primary);
            background: rgba(79, 70, 229, 0.10);
            font-weight: 600;
        }
        .nav-links .nav-badge {
            display: inline-block;
            background: var(--accent-green);
            color: #fff;
            font-size: 0.68rem;
            padding: 2px 7px;
            border-radius: 10px;
            margin-left: 4px;
            font-weight: 600;
            letter-spacing: 0.02em;
        }

        /* 面包屑 */
        .breadcrumb {
            max-width: 1240px;
            margin: 18px auto 0;
            padding: 0 24px;
            font-size: 0.85rem;
            color: var(--text-muted);
            display: flex;
            align-items: center;
            gap: 6px;
        }
        .breadcrumb a {
            color: var(--text-muted);
            text-decoration: none;
            transition: color var(--transition);
        }
        .breadcrumb a:hover {
            color: var(--primary);
        }
        .breadcrumb .sep {
            user-select: none;
            opacity: 0.5;
        }

        .container {
            max-width: 900px;
            margin: 0 auto;
            padding: 32px 24px 48px;
        }

        /* 页面头部 */
        .page-header {
            text-align: center;
            padding: 40px 20px 30px;
            margin-bottom: 40px;
        }
        .page-header h1 {
            font-size: clamp(1.8rem, 4vw, 2.5rem);
            font-weight: 800;
            color: #0f172a;
            letter-spacing: -0.03em;
            margin-bottom: 12px;
        }
        .page-header .highlight {
            background: linear-gradient(135deg, var(--primary) 0%, var(--accent) 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        .page-header p {
            font-size: 1.1rem;
            color: var(--text-secondary);
            max-width: 620px;
            margin: 0 auto;
        }

        /* 分类导航卡片 */
        .category-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
            gap: 16px;
            margin-bottom: 44px;
        }
        .category-card {
            background: var(--bg);
            border: 1px solid var(--border);
            border-radius: var(--radius);
            padding: 20px 15px;
            text-align: center;
            text-decoration: none;
            color: var(--text);
            transition: all var(--transition);
            box-shadow: var(--shadow-sm);
            display: block;
        }
        .category-card:hover {
            transform: translateY(-3px);
            box-shadow: var(--shadow-md);
            border-color: var(--primary-light);
            color: var(--primary);
        }
        .category-card .emoji {
            font-size: 2rem;
            display: block;
            margin-bottom: 6px;
        }
        .category-card .label {
            font-weight: 600;
            font-size: 0.95rem;
        }

        /* FAQ 分类区块 */
        .faq-category {
            margin-bottom: 36px;
        }
        .faq-category h2 {
            font-size: 1.5rem;
            font-weight: 700;
            color: #0f172a;
            padding-bottom: 10px;
            border-bottom: 3px solid var(--border-light);
            margin-bottom: 16px;
            display: flex;
            align-items: center;
            gap: 10px;
        }
        .faq-category h2 .icon {
            font-size: 1.6rem;
        }

        /* 折叠问答卡片 (details) */
        .faq-item {
            background: var(--bg);
            border: 1px solid var(--border);
            border-radius: var(--radius);
            margin-bottom: 12px;
            overflow: hidden;
            transition: all var(--transition);
            box-shadow: var(--shadow-sm);
        }
        .faq-item:hover {
            box-shadow: var(--shadow-md);
            border-color: #cbd5e1;
        }
        .faq-item summary {
            padding: 18px 22px;
            font-weight: 600;
            font-size: 1.05rem;
            color: var(--text);
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
            list-style: none;
            transition: color var(--transition);
        }
        .faq-item summary::-webkit-details-marker {
            display: none;
        }
        .faq-item summary .arrow {
            font-size: 1.2rem;
            transition: transform var(--transition);
            color: var(--text-muted);
            flex-shrink: 0;
        }
        .faq-item[open] summary .arrow {
            transform: rotate(180deg);
            color: var(--primary);
        }
        .faq-item[open] summary {
            color: var(--primary);
        }
        .faq-answer {
            padding: 0 22px 20px;
            color: var(--text-secondary);
            text-align: justify;
            line-height: 1.8;
        }
        .faq-answer p {
            margin-bottom: 10px;
        }
        .faq-answer p:last-child {
            margin-bottom: 0;
        }
        .faq-answer code {
            background: var(--bg-card);
            padding: 2px 8px;
            border-radius: 4px;
            font-family: var(--font-mono);
            font-size: 0.9rem;
            color: #db2777;
        }
        .faq-answer ul {
            margin: 6px 0 12px 20px;
        }
        .faq-answer li {
            margin-bottom: 4px;
        }

        /* 支持区域 */
        .support-box {
            background: linear-gradient(135deg, #eef2ff 0%, #e0f2fe 100%);
            border-radius: var(--radius-lg);
            padding: 36px 24px;
            text-align: center;
            margin-top: 48px;
            border: 1px solid #bae6fd;
        }
        .support-box h3 {
            font-size: 1.4rem;
            color: #1e3a8a;
            margin-bottom: 10px;
        }
        .support-box p {
            color: #1e40af;
            margin-bottom: 22px;
        }
        .btn {
            display: inline-block;
            padding: 12px 28px;
            border-radius: 28px;
            text-decoration: none;
            font-weight: 600;
            background: var(--primary);
            color: #fff;
            transition: all var(--transition);
            box-shadow: 0 4px 14px rgba(79, 70, 229, 0.30);
        }
        .btn:hover {
            background: var(--primary-dark);
            box-shadow: 0 6px 22px rgba(79, 70, 229, 0.40);
            transform: translateY(-1px);
        }

        /* 页脚 */
        footer {
            background: var(--bg-soft);
            text-align: center;
            padding: 36px 20px;
            margin-top: 56px;
            border-top: 1px solid var(--border);
            color: var(--text-muted);
            font-size: 0.88rem;
            line-height: 1.8;
        }
        .footer-links {
            display: flex;
            justify-content: center;
            list-style: none;
            gap: 18px;
            margin-bottom: 14px;
            flex-wrap: wrap;
        }
        .footer-links a {
            text-decoration: none;
            color: var(--text-secondary);
            font-weight: 500;
            transition: color var(--transition);
            font-size: 0.9rem;
        }
        .footer-links a:hover {
            color: var(--primary);
        }
        .footer-note {
            font-size: 0.78rem;
            color: #94a3b8;
            margin-top: 6px;
        }

        /* 响应式 */
        @media (max-width: 768px) {
            .nav-container {
                flex-direction: column;
                gap: 10px;
                padding: 12px 16px;
            }
            .nav-links a {
                padding: 7px 11px;
                font-size: 0.85rem;
            }
            .page-header h1 {
                font-size: 1.6rem;
            }
            .category-grid {
                grid-template-columns: 1fr 1fr;
            }
            .footer-links {
                gap: 10px;
            }
        }
        @media (max-width: 420px) {
            .category-grid {
                grid-template-columns: 1fr;
            }
        }