:root {
            --bg-main: #060813;
            --bg-surface: #0e1329;
            --bg-card: rgba(18, 26, 52, 0.6);
            --bg-card-alt: rgba(14, 19, 41, 0.8);
            --border-color: rgba(99, 102, 241, 0.2);
            --border-hover: rgba(168, 85, 247, 0.5);
            --border-cyan: rgba(6, 182, 212, 0.35);
            --primary: #6366f1;
            --secondary: #a855f7;
            --cyan: #06b6d4;
            --green: #10b981;
            --amber: #f59e0b;
            --text-main: #f8fafc;
            --text-muted: #94a3b8;
            --text-dim: #64748b;
            --radius-sm: 8px;
            --radius-md: 14px;
            --radius-lg: 20px;
            --radius-xl: 28px;
            --transition-fast: 0.2s ease;
            --transition-smooth: 0.35s cubic-bezier(0.4, 0, 0.2, 1);
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
        }

        body {
            background-color: var(--bg-main);
            color: var(--text-main);
            line-height: 1.65;
            overflow-x: hidden;
            -webkit-font-smoothing: antialiased;
        }

        .bg-aurora {
            position: fixed;
            top: 0;
            left: 0;
            width: 100vw;
            height: 100vh;
            z-index: -1;
            pointer-events: none;
            overflow: hidden;
        }
        .aurora-1 {
            position: absolute;
            top: -10%;
            right: 20%;
            width: 50vw;
            height: 50vw;
            background: radial-gradient(circle, rgba(6, 182, 212, 0.12) 0%, rgba(0,0,0,0) 70%);
            filter: blur(100px);
            animation: drift1 18s infinite;
        }
        .aurora-2 {
            position: absolute;
            bottom: -10%;
            left: 10%;
            width: 45vw;
            height: 45vw;
            background: radial-gradient(circle, rgba(168, 85, 247, 0.1) 0%, rgba(0,0,0,0) 70%);
            filter: blur(110px);
            animation: drift2 22s infinite;
        }
        @keyframes drift1 {
            0%,100%{transform:translate(0,0);}
            50%{transform:translate(2vw,-1.5vw);}
        }
        @keyframes drift2 {
            0%,100%{transform:translate(0,0);}
            50%{transform:translate(-2vw,1.5vw);}
        }

        header {
            position: sticky;
            top: 0;
            z-index: 1000;
            background: rgba(6, 8, 19, 0.82);
            backdrop-filter: blur(22px);
            -webkit-backdrop-filter: blur(22px);
            border-bottom: 1px solid var(--border-color);
        }
        .header-wrap {
            max-width: 1280px;
            margin: 0 auto;
            padding: 0.9rem 2rem;
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 1rem;
        }
        .brand {
            display: flex;
            align-items: center;
            gap: 0.7rem;
            text-decoration: none;
            color: #fff;
            flex-shrink: 0;
        }
        .brand-logo {
            width: 38px;
            height: 38px;
            background: linear-gradient(135deg, var(--cyan), var(--primary), var(--secondary));
            border-radius: 11px;
            display: flex;
            align-items: center;
            justify-content: center;
            box-shadow: 0 0 22px rgba(6, 182, 212, 0.45);
        }
        .brand-title {
            font-size: 1.3rem;
            font-weight: 800;
            letter-spacing: -0.5px;
            background: linear-gradient(135deg, #ffffff 40%, #bae6fd 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }
        .nav-menu {
            display: flex;
            list-style: none;
            gap: 1.6rem;
            flex-wrap: wrap;
        }
        .nav-link {
            color: var(--text-muted);
            text-decoration: none;
            font-size: 0.93rem;
            font-weight: 500;
            position: relative;
        }
        .nav-link::after {
            content: '';
            position: absolute;
            bottom: -4px;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--cyan);
            border-radius: 2px;
            transition: width var(--transition-smooth);
        }
        .nav-link:hover,
        .nav-link.active {
            color: var(--cyan);
        }
        .nav-link:hover::after,
        .nav-link.active::after {
            width: 100%;
        }
        .nav-btn {
            background: linear-gradient(135deg, var(--cyan), var(--primary));
            color: #fff;
            padding: 0.6rem 1.4rem;
            border-radius: var(--radius-sm);
            text-decoration: none;
            font-size: 0.88rem;
            font-weight: 600;
            box-shadow: 0 4px 16px rgba(6, 182, 212, 0.3);
            transition: all var(--transition-smooth);
            white-space: nowrap;
        }
        .nav-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 8px 24px rgba(6, 182, 212, 0.55);
        }

        .page-header {
            text-align: center;
            max-width: 800px;
            margin: 4rem auto 2rem;
            padding: 0 1.5rem;
        }
        .page-header h1 {
            font-size: 2.8rem;
            font-weight: 800;
            margin-bottom: 1rem;
        }
        .text-gradient {
            background: linear-gradient(135deg, #fff 20%, var(--cyan) 60%, var(--secondary) 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }
        .page-header p {
            color: var(--text-muted);
            font-size: 1.05rem;
        }

        /* 智能搜索 */
        .search-section {
            max-width: 700px;
            margin: 2rem auto 3rem;
            padding: 0 2rem;
        }
        .search-box {
            display: flex;
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: 99px;
            overflow: hidden;
            transition: var(--transition-smooth);
        }
        .search-box:focus-within {
            border-color: var(--border-hover);
            box-shadow: 0 0 20px rgba(99,102,241,0.2);
        }
        .search-input {
            flex: 1;
            background: transparent;
            border: none;
            padding: 1rem 1.5rem;
            color: #fff;
            font-size: 0.95rem;
            outline: none;
        }
        .search-input::placeholder {
            color: var(--text-dim);
        }
        .search-btn {
            background: linear-gradient(135deg, var(--cyan), var(--primary));
            border: none;
            padding: 0 2rem;
            color: #fff;
            font-weight: 700;
            cursor: pointer;
            transition: var(--transition-smooth);
        }
        .search-btn:hover {
            background: linear-gradient(135deg, #22d3ee, var(--primary));
        }
        .search-hint {
            text-align: center;
            color: var(--text-dim);
            font-size: 0.8rem;
            margin-top: 0.6rem;
        }

        /* 五大分类 */
        .category-grid {
            max-width: 1280px;
            margin: 3rem auto;
            padding: 0 2rem;
            display: grid;
            grid-template-columns: repeat(5, 1fr);
            gap: 1.2rem;
        }
        .category-card {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-lg);
            padding: 1.8rem 1rem;
            text-align: center;
            transition: var(--transition-smooth);
            cursor: pointer;
        }
        .category-card:hover {
            border-color: var(--border-hover);
            transform: translateY(-5px);
            box-shadow: 0 15px 35px rgba(0,0,0,0.4);
        }
        .category-icon {
            font-size: 2.2rem;
            margin-bottom: 0.8rem;
        }
        .category-card h3 {
            font-size: 1rem;
            color: #fff;
            margin-bottom: 0.4rem;
        }
        .category-card p {
            font-size: 0.75rem;
            color: var(--text-muted);
        }

        /* 热门问题（扩展版） */
        .faq-hot {
            max-width: 900px;
            margin: 4rem auto;
            padding: 0 2rem;
        }
        .faq-hot h2 {
            text-align: center;
            font-size: 2rem;
            font-weight: 800;
            margin-bottom: 2rem;
        }
        .faq-list {
            display: flex;
            flex-direction: column;
            gap: 0.9rem;
        }
        .faq-item {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-md);
            padding: 1.2rem 1.5rem;
            transition: var(--transition-fast);
        }
        .faq-item:hover {
            border-color: var(--border-cyan);
            background: rgba(18,26,52,0.8);
        }
        .faq-item summary {
            font-weight: 700;
            color: #fff;
            cursor: pointer;
            list-style: none;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        .faq-item summary::-webkit-details-marker {
            display: none;
        }
        .faq-item p,
        .faq-item .answer-content {
            color: var(--text-muted);
            font-size: 0.9rem;
            margin-top: 0.8rem;
            line-height: 1.7;
        }
        .faq-item .answer-content ol,
        .faq-item .answer-content ul {
            margin-left: 1.2rem;
            margin-top: 0.5rem;
        }
        .faq-item .answer-content li {
            margin-bottom: 0.3rem;
        }
        .faq-item .answer-content strong {
            color: #fff;
        }

        /* 自助诊断 */
        .diagnostic-tool {
            max-width: 1000px;
            margin: 4rem auto;
            padding: 2.5rem;
            background: var(--bg-card-alt);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-xl);
            text-align: center;
        }
        .diagnostic-tool h2 {
            font-size: 2rem;
            font-weight: 800;
            margin-bottom: 1rem;
        }
        .tool-buttons {
            display: flex;
            gap: 1.2rem;
            justify-content: center;
            flex-wrap: wrap;
            margin-top: 1.5rem;
        }
        .tool-btn {
            background: rgba(255,255,255,0.04);
            border: 1px solid var(--border-color);
            color: #fff;
            padding: 0.8rem 1.5rem;
            border-radius: var(--radius-md);
            font-weight: 600;
            cursor: pointer;
            transition: var(--transition-smooth);
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        .tool-btn:hover {
            border-color: var(--cyan);
            background: rgba(6,182,212,0.08);
        }

        /* 图文教程 */
        .tutorial-section {
            max-width: 1280px;
            margin: 4rem auto;
            padding: 0 2rem;
        }
        .tutorial-section h2 {
            text-align: center;
            font-size: 2rem;
            font-weight: 800;
            margin-bottom: 2rem;
        }
        .tutorial-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 2rem;
        }
        .tutorial-card {
            background: var(--bg-card);
            border: 1px solid var(--border-color);
            border-radius: var(--radius-lg);
            overflow: hidden;
            transition: var(--transition-smooth);
        }
        .tutorial-card:hover {
            border-color: var(--border-hover);
            transform: translateY(-5px);
        }
        .tutorial-img {
            width: 100%;
            height: 140px;
            background: rgba(99,102,241,0.1);
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 2.5rem;
        }
        .tutorial-content {
            padding: 1.2rem;
        }
        .tutorial-content h4 {
            color: #fff;
            margin-bottom: 0.5rem;
        }
        .tutorial-content p {
            color: var(--text-muted);
            font-size: 0.85rem;
        }

        footer {
            background: #03040a;
            border-top: 1px solid var(--border-color);
            padding: 4rem 2rem 2rem;
        }
        .footer-grid {
            max-width: 1280px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: 2fr repeat(3, 1fr);
            gap: 3rem;
            margin-bottom: 3rem;
        }
        .footer-brand p {
            color: var(--text-muted);
            font-size: 0.88rem;
            margin-top: 1rem;
            max-width: 300px;
        }
        .footer-col h4 {
            color: #fff;
            font-size: 0.95rem;
            margin-bottom: 1.1rem;
        }
        .footer-col ul {
            list-style: none;
        }
        .footer-col li {
            margin-bottom: 0.7rem;
        }
        .footer-col a {
            color: var(--text-muted);
            text-decoration: none;
            font-size: 0.88rem;
        }
        .footer-col a:hover {
            color: #fff;
        }
        .footer-bottom {
            max-width: 1280px;
            margin: 0 auto;
            padding-top: 2rem;
            border-top: 1px solid rgba(255,255,255,0.04);
            display: flex;
            justify-content: space-between;
            color: var(--text-muted);
            font-size: 0.82rem;
            flex-wrap: wrap;
            gap: 1rem;
        }

        @media (max-width: 992px) {
            .category-grid { grid-template-columns: repeat(3,1fr); }
            .tutorial-grid { grid-template-columns: 1fr; }
            .footer-grid { grid-template-columns: 1fr 1fr; }
        }
        @media (max-width: 600px) {
            .category-grid { grid-template-columns: 1fr 1fr; }
            .footer-grid { grid-template-columns: 1fr; }
        }