:root {
            --red: #ef443b;
            --red-dark: #c0392b;
            --text: #1a1a1a;
            --text2: #4a4a4a;
            --gray-light: #f7f8fa;
            --gray-border: #e8eaef;
            --white: #fff;
            --radius: 16px;
            --radius-sm: 8px;
            --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.04);
            --shadow: 0 8px 30px rgba(0, 0, 0, 0.06);
            --transition: 0.28s cubic-bezier(0.4, 0, 0.2, 1);
            --max-w: 1280px;
        }

        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        html {
            scroll-behavior: smooth;
        }
        body {
            font-family: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', system-ui, sans-serif;
            color: var(--text);
            background: #fefefe;
            line-height: 1.6;
            -webkit-font-smoothing: antialiased;
        }
        img {
            max-width: 100%;
            height: auto;
            display: block;
        }
        a {
            text-decoration: none;
            color: inherit;
        }
        ul {
            list-style: none;
        }

        /* ===== 导航栏（与首页完全一致） ===== */
        .nav {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            z-index: 1000;
            background: rgba(255, 255, 255, 0.88);
            backdrop-filter: blur(14px);
            -webkit-backdrop-filter: blur(14px);
            border-bottom: 1px solid rgba(0, 0, 0, 0.05);
            height: 64px;
            display: flex;
            align-items: center;
            padding: 0 5%;
            justify-content: space-between;
            transition: var(--transition);
        }
        .nav-logo img {
            height: 28px;
            width: auto;
        }
        .nav-links {
            display: flex;
            align-items: center;
            gap: 6px;
            flex-wrap: wrap;
        }
        .nav-links a {
            font-size: 14px;
            font-weight: 500;
            color: #333;
            padding: 8px 14px;
            border-radius: 20px;
            transition: var(--transition);
            white-space: nowrap;
        }
        .nav-links a:hover {
            background: #fff0ef;
            color: var(--red);
        }
        .nav-cta {
            display: flex;
            align-items: center;
            gap: 10px;
        }
        .btn-nav-dl {
            background: var(--red);
            color: #fff;
            font-weight: 600;
            font-size: 14px;
            padding: 9px 20px;
            border-radius: 22px;
            transition: var(--transition);
            white-space: nowrap;
        }
        .btn-nav-dl:hover {
            background: var(--red-dark);
            transform: translateY(-1px);
            box-shadow: 0 4px 14px rgba(239, 68, 59, 0.35);
        }

        /* ===== FAQ 头部 ===== */
        .faq-hero {
            padding: 150px 5% 50px;
            background: radial-gradient(circle at 50% 0%, rgba(239, 68, 68, 0.04) 0%, rgba(255, 255, 255, 1) 70%);
            text-align: center;
        }
        .faq-hero h1 {
            font-size: clamp(2.2rem, 4vw, 3rem);
            font-weight: 700;
            color: #1f2937;
            margin-bottom: 15px;
        }
        .faq-hero h1 .hl {
            background: linear-gradient(135deg, #ef443b 0%, #ee6b3b 100%);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
            background-clip: text;
        }
        .faq-hero p {
            font-size: 1.15rem;
            color: #4b5563;
            font-weight: 400;
            max-width: 680px;
            margin: 0 auto;
            line-height: 1.7;
        }

        /* ===== 快速导航卡片（创意版块） ===== */
        .quick-nav-cards {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 18px;
            max-width: 900px;
            margin: 40px auto 30px;
            padding: 0 5%;
        }
        .quick-nav-card {
            background: #fff;
            border: 1px solid #f0f0f0;
            border-radius: 40px;
            padding: 12px 24px;
            font-weight: 600;
            font-size: 0.95rem;
            color: #4b5563;
            display: flex;
            align-items: center;
            gap: 8px;
            transition: var(--transition);
            white-space: nowrap;
        }
        .quick-nav-card:hover {
            border-color: var(--red);
            color: var(--red);
            transform: translateY(-2px);
            box-shadow: 0 6px 16px rgba(239, 68, 59, 0.08);
        }
        .quick-nav-card .dot {
            width: 8px;
            height: 8px;
            border-radius: 50%;
            background: var(--red);
            flex-shrink: 0;
        }

        /* ===== FAQ 容器 ===== */
        .faq-container {
            max-width: 900px;
            margin: 0 auto 70px;
            padding: 0 5%;
        }
        .faq-group {
            margin-bottom: 50px;
            scroll-margin-top: 100px;
        }
        .faq-group-title {
            font-size: 1.6rem;
            font-weight: 700;
            color: var(--red);
            margin-bottom: 22px;
            padding-left: 14px;
            border-left: 4px solid var(--red);
        }
        .faq-item {
            background: #ffffff;
            border: 1px solid #e5e7eb;
            border-radius: 12px;
            margin-bottom: 14px;
            overflow: hidden;
            transition: border-color 0.3s, box-shadow 0.3s;
        }
        .faq-item:hover {
            border-color: #ffbabb;
            box-shadow: 0 10px 25px rgba(239, 68, 68, 0.03);
        }
        .faq-checkbox {
            display: none;
        }
        .faq-trigger {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 22px 28px;
            cursor: pointer;
            user-select: none;
        }
        .faq-trigger h3 {
            font-size: 1.1rem;
            color: #1f2937;
            font-weight: 700;
            padding-right: 20px;
        }
        .faq-icon {
            width: 16px;
            height: 16px;
            position: relative;
            transition: transform 0.3s ease;
            flex-shrink: 0;
        }
        .faq-icon::before,
        .faq-icon::after {
            content: '';
            position: absolute;
            background-color: #9ca3af;
            transition: background-color 0.3s;
        }
        .faq-icon::before {
            top: 7px;
            left: 0;
            width: 16px;
            height: 2px;
        }
        .faq-icon::after {
            top: 0;
            left: 7px;
            width: 2px;
            height: 16px;
        }
        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.4s cubic-bezier(0.4, 0, 0.2, 1);
            background: #fafafa;
        }
        .faq-answer-content {
            padding: 0 28px 22px;
        }
        .faq-answer-content p {
            font-size: 1rem;
            color: #4b5563;
            line-height: 1.8;
            font-weight: 400;
            margin-bottom: 12px;
        }
        .faq-answer-content p strong {
            font-weight: 700;
            color: #000;
        }
        .faq-media-box {
            margin: 18px 0 10px;
            background: #ffffff;
            border: 1px dashed #d1d5db;
            border-radius: 10px;
            padding: 15px;
            text-align: center;
        }
        .faq-media-box img {
            max-width: 100%;
            height: auto;
            border-radius: 4px;
            display: block;
            margin: 0 auto;
        }
        .faq-media-caption {
            font-size: 0.8rem;
            color: #9ca3af;
            margin-top: 8px;
            font-weight: 500;
        }
        /* 手风琴展开状态 */
        .faq-checkbox:checked~.faq-answer {
            max-height: 1800px;
            border-top: 1px solid #f3f4f6;
        }
        .faq-checkbox:checked~.faq-trigger .faq-icon {
            transform: rotate(45deg);
        }
        .faq-checkbox:checked~.faq-trigger .faq-icon::before,
        .faq-checkbox:checked~.faq-trigger .faq-icon::after {
            background-color: var(--red);
        }
        .faq-checkbox:checked~.faq-trigger h3 {
            color: var(--red);
        }

        /* ===== 创意版块：智能诊断引导 ===== */
        .troubleshoot-promo {
            max-width: 900px;
            margin: 0 auto 80px;
            padding: 0 5%;
            display: flex;
            align-items: center;
            gap: 35px;
            background: linear-gradient(135deg, #fff5f5 0%, #fff 100%);
            border-radius: 24px;
            border: 1px solid #fed7d7;
            padding: 45px 40px;
            flex-wrap: wrap;
        }
        .promo-content {
            flex: 1;
            min-width: 260px;
        }
        .promo-content h2 {
            font-size: 1.9rem;
            font-weight: 700;
            margin-bottom: 15px;
            color: #1f2937;
        }
        .promo-content h2 .hl {
            color: var(--red);
        }
        .promo-content p {
            font-size: 1.05rem;
            color: #4b5563;
            margin-bottom: 25px;
            line-height: 1.7;
        }
        .promo-actions {
            display: flex;
            gap: 14px;
            margin-bottom: 18px;
            flex-wrap: wrap;
        }
        .btn-promo-primary {
            background: var(--red);
            color: #fff;
            padding: 12px 28px;
            border-radius: 8px;
            text-decoration: none;
            font-weight: 700;
            transition: 0.3s;
            display: inline-block;
        }
        .btn-promo-primary:hover {
            background: #d93833;
            transform: translateY(-2px);
            box-shadow: 0 8px 20px rgba(239, 68, 59, 0.3);
        }
        .btn-promo-outline {
            border: 2px solid var(--red);
            color: var(--red);
            padding: 12px 28px;
            border-radius: 8px;
            text-decoration: none;
            font-weight: 700;
            transition: 0.3s;
            display: inline-block;
        }
        .btn-promo-outline:hover {
            background: var(--red);
            color: #fff;
        }
        .promo-tip {
            font-size: 0.9rem;
            color: #9ca3af;
        }
        .promo-tip a {
            color: var(--red);
            text-decoration: none;
            font-weight: 600;
        }
        .promo-visual {
            flex: 0 0 240px;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        .promo-visual img {
            width: 100%;
            height: auto;
            background: #fff;
            border-radius: 16px;
            box-shadow: 0 10px 25px rgba(0, 0, 0, 0.04);
        }

        /* ===== 页脚（与首页完全一致） ===== */
        .footer {
            background: #111;
            color: #ccc;
            padding: 60px 5% 30px;
        }
        .footer-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
            gap: 30px;
            max-width: var(--max-w);
            margin: 0 auto;
        }
        .footer-col h4 {
            color: #fff;
            font-size: 1rem;
            font-weight: 700;
            margin-bottom: 16px;
            position: relative;
            padding-bottom: 10px;
        }
        .footer-col h4::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 28px;
            height: 2px;
            background: var(--red);
            border-radius: 1px;
        }
        .footer-col ul li {
            margin-bottom: 8px;
        }
        .footer-col ul li a {
            color: #aaa;
            font-size: 13px;
            transition: var(--transition);
        }
        .footer-col ul li a:hover {
            color: #fff;
        }
        .footer-bottom {
            max-width: var(--max-w);
            margin: 40px auto 0;
            padding-top: 20px;
            border-top: 1px solid #2a2a2a;
            display: flex;
            justify-content: space-between;
            align-items: center;
            flex-wrap: wrap;
            gap: 12px;
            font-size: 12px;
            color: #777;
        }
        .footer-bottom a {
            color: #999;
            margin-left: 16px;
            transition: var(--transition);
        }
        .footer-bottom a:hover {
            color: #fff;
        }

        /* ===== 响应式 ===== */
        @media (max-width: 768px) {
            .nav-links {
                display: none;
            }
            .faq-trigger {
                padding: 18px 20px;
            }
            .faq-answer-content {
                padding: 0 20px 18px;
            }
            .troubleshoot-promo {
                padding: 30px 20px;
                flex-direction: column;
                text-align: center;
            }
            .promo-actions {
                justify-content: center;
            }
            .promo-visual {
                flex: 0 0 auto;
                width: 70%;
                margin: 0 auto;
            }
        }