:root {
            --accent: #4f46e5;
            --accent-dark: #3730a3;
            --accent-light: #eef2ff;
            --accent-soft: #f5f3ff;
            --bg: #fafbfc;
            --surface: #ffffff;
            --text: #1a1a2e;
            --text-secondary: #3d3d5c;
            --text-muted: #6b6b80;
            --border: #e2e4ea;
            --border-light: #eff1f5;
            --shadow-sm: 0 1px 4px rgba(30, 30, 50, 0.04);
            --shadow-md: 0 6px 20px rgba(30, 30, 50, 0.06);
            --shadow-lg: 0 16px 36px rgba(30, 30, 50, 0.09);
            --radius-sm: 14px;
            --radius-md: 22px;
            --radius-lg: 34px;
            --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(79, 70, 229, 0.025) 0%, transparent 55%),
                radial-gradient(ellipse at 80% 55%, rgba(99, 102, 241, 0.018) 0%, transparent 48%),
                radial-gradient(ellipse at 35% 82%, rgba(79, 70, 229, 0.012) 0%, transparent 42%);
            background-attachment: fixed;
        }
        .container {
            max-width: 1220px;
            margin: 0 auto;
            padding: 0 26px;
        }
        header {
            background: rgba(255, 255, 255, 0.86);
            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: 14px 0;
            gap: 10px;
        }
        .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(79, 70, 229, 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: 6px;
            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(79, 70, 229, 0.24);
            transition: var(--transition) !important;
        }
        .btn-download-nav:hover {
            background: var(--accent-dark) !important;
            transform: translateY(-2px);
            box-shadow: 0 6px 18px rgba(79, 70, 229, 0.32);
        }

        .section {
            padding: 34px 0 42px;
        }
        .section-title {
            text-align: center;
            font-size: clamp(1.5rem, 2.6vw, 1.95rem);
            font-weight: 750;
            margin-bottom: 8px;
            color: var(--text);
            letter-spacing: -0.3px;
        }
        .section-subtitle {
            text-align: center;
            color: var(--text-muted);
            margin-bottom: 28px;
            font-size: 0.95rem;
            max-width: 600px;
            margin-left: auto;
            margin-right: auto;
        }
        .section-title::after {
            content: '';
            display: block;
            width: 48px;
            height: 3.5px;
            background: var(--accent);
            border-radius: 3px;
            margin: 10px auto 0;
        }

        /* 分类标签 */
        .category-tabs {
            display: flex;
            flex-wrap: wrap;
            gap: 8px;
            justify-content: center;
            margin-bottom: 18px;
        }
        .cat-tab {
            padding: 8px 20px;
            border-radius: var(--radius-full);
            background: var(--surface);
            border: 1px solid var(--border);
            font-weight: 600;
            font-size: 0.88rem;
            cursor: pointer;
            transition: var(--transition);
            color: var(--text-secondary);
            white-space: nowrap;
        }
        .cat-tab:hover {
            border-color: var(--accent);
            color: var(--accent);
            background: var(--accent-light);
        }
        .cat-tab.active-tab {
            background: var(--accent);
            color: #fff;
            border-color: var(--accent);
            box-shadow: 0 4px 14px rgba(79, 70, 229, 0.32);
        }

        /* 错误代码检索器 */
        .search-box {
            max-width: 500px;
            margin: 0 auto 30px;
            position: relative;
        }
        .search-input {
            width: 100%;
            padding: 13px 20px 13px 44px;
            border-radius: var(--radius-full);
            border: 1.5px solid var(--border);
            background: var(--surface);
            font-size: 0.95rem;
            font-family: var(--font-stack);
            transition: var(--transition);
            box-shadow: var(--shadow-sm);
            outline: none;
        }
        .search-input:focus {
            border-color: var(--accent);
            box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.12);
        }
        .search-icon {
            position: absolute;
            left: 16px;
            top: 50%;
            transform: translateY(-50%);
            font-size: 1.1rem;
            color: var(--text-muted);
            pointer-events: none;
        }

        /* FAQ 列表 */
        .faq-list {
            max-width: 850px;
            margin: 0 auto;
            display: flex;
            flex-direction: column;
            gap: 10px;
        }
        .faq-card {
            background: var(--surface);
            border-radius: var(--radius-md);
            border: 1px solid var(--border-light);
            box-shadow: var(--shadow-sm);
            overflow: hidden;
            transition: var(--transition);
        }
        .faq-card:hover {
            border-color: var(--accent);
            box-shadow: var(--shadow-md);
        }
        .faq-summary {
            display: flex;
            align-items: flex-start;
            justify-content: space-between;
            padding: 18px 22px;
            cursor: pointer;
            user-select: none;
            gap: 15px;
        }
        .faq-left {
            flex: 1;
        }
        .faq-question {
            font-weight: 700;
            font-size: 1.02rem;
            color: var(--text);
            margin-bottom: 4px;
            letter-spacing: -0.2px;
        }
        .faq-short-answer {
            font-size: 0.86rem;
            color: var(--text-secondary);
            line-height: 1.5;
            margin-top: 2px;
        }
        .faq-arrow {
            font-size: 1.3rem;
            color: var(--accent);
            transition: transform 0.3s ease;
            flex-shrink: 0;
            margin-top: 2px;
        }
        .faq-card.open .faq-arrow {
            transform: rotate(180deg);
        }
        .faq-detail {
            padding: 0 22px;
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.35s ease, padding 0.35s ease;
            background: #fbfbff;
            border-top: 1px solid transparent;
        }
        .faq-card.open .faq-detail {
            max-height: 500px;
            padding: 16px 22px;
            border-top-color: var(--border-light);
        }
        .faq-detail p {
            font-size: 0.88rem;
            color: var(--text-secondary);
            line-height: 1.7;
            margin-bottom: 8px;
        }
        .faq-detail ul {
            margin: 8px 0;
            padding-left: 20px;
        }
        .faq-detail li {
            font-size: 0.86rem;
            color: var(--text-secondary);
            margin-bottom: 4px;
        }
        .highlight {
            background: var(--accent-light);
            padding: 2px 6px;
            border-radius: 6px;
            font-weight: 600;
            color: var(--accent);
        }
        .no-results {
            text-align: center;
            color: var(--text-muted);
            padding: 30px;
            font-size: 0.95rem;
        }

        /* Footer */
        .footer {
            background: #16152a;
            color: #b8b8cc;
            padding: 40px 0 20px;
            border-radius: var(--radius-lg) var(--radius-lg) 0 0;
        }
        .footer-grid {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
            gap: 28px;
        }
        .footer-col h4 {
            color: #fff;
            margin-bottom: 10px;
            font-size: 0.93rem;
            letter-spacing: -0.12px;
        }
        .footer-col a {
            color: #b8b8cc;
            text-decoration: none;
            display: block;
            margin-bottom: 5px;
            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: 26px;
            font-size: 0.8rem;
            border-top: 1px solid #2a2840;
            margin-top: 20px;
            color: #8a8a9c;
        }
        .footer-disclaimer {
            text-align: center;
            font-size: 0.74rem;
            color: #6e6e80;
            margin-top: 8px;
            line-height: 1.5;
        }

        @media (max-width: 900px) {
            .nav-bar {
                flex-direction: column;
                align-items: stretch;
            }
            .nav-links {
                gap: 4px;
                font-size: 0.82rem;
            }
            .nav-links a {
                padding: 6px 11px;
            }
        }
        @media (max-width: 480px) {
            .container {
                padding: 0 12px;
            }
            .faq-summary {
                padding: 14px 16px;
            }
            .faq-detail {
                padding: 0 16px;
            }
            .faq-card.open .faq-detail {
                padding: 14px 16px;
            }
        }