/* roulang page: index */
:root {
      --primary-dark: #111827;
      --secondary-dark: #0b0f17;
      --accent-teal: #0d9488;
      --accent-emerald: #10b981;
      --accent-amber: #f59e0b;
      --bg-light: #f3f4f6;
      --bg-white: #ffffff;
      --text-main: #1f2937;
      --text-muted: #4b5563;
      --border-color: #e5e7eb;
      --mono-font: "JetBrains Mono", Consolas, Menlo, monospace;
      --sans-font: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      --radius: 6px;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.05);
      --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    }
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; font-size: 16px; }
    body { font-family: var(--sans-font); background-color: var(--bg-white); color: var(--text-main); line-height: 1.7; -webkit-font-smoothing: antialiased; }
    a { color: inherit; text-decoration: none; transition: all 0.2s ease; }
    img { max-width: 100%; height: auto; display: block; }
    button, input, textarea, select { font-family: inherit; font-size: inherit; }
    
    .container { width: 100%; max-width: 1240px; margin: 0 auto; padding: 0 20px; }
    .section-spacing { padding: 80px 0; }
    .section-alt { background-color: var(--bg-light); border-top: 1px solid var(--border-color); border-bottom: 1px solid var(--border-color); }
    .section-dark { background-color: var(--secondary-dark); color: #f9fafb; }
    
    .sec-header { margin-bottom: 48px; max-width: 820px; }
    .sec-header.center { margin-left: auto; margin-right: auto; text-align: center; }
    .sec-tag { display: inline-block; font-size: 13px; font-weight: 600; text-transform: uppercase; letter-spacing: 1px; color: var(--accent-teal); margin-bottom: 12px; background: rgba(13, 148, 136, 0.1); padding: 4px 10px; border-radius: 4px; border: 1px solid rgba(13, 148, 136, 0.2); }
    .section-dark .sec-tag { color: var(--accent-emerald); background: rgba(16, 185, 129, 0.15); border-color: rgba(16, 185, 129, 0.3); }
    .sec-title { font-size: 32px; font-weight: 700; line-height: 1.3; color: var(--primary-dark); margin-bottom: 16px; letter-spacing: -0.5px; }
    .section-dark .sec-title { color: #ffffff; }
    .sec-desc { font-size: 16px; color: var(--text-muted); line-height: 1.8; }
    .section-dark .sec-desc { color: #9ca3af; }

    /* 顶部导航 */
    .top-utility-bar { background-color: var(--secondary-dark); color: #9ca3af; font-size: 13px; border-bottom: 1px solid #1f2937; }
    .utility-inner { display: flex; justify-content: space-between; align-items: center; height: 38px; }
    .utility-left span, .utility-right span { margin-right: 20px; }
    .utility-left strong { color: var(--accent-emerald); font-weight: 600; }
    .lang-switch { color: #d1d5db; font-family: var(--mono-font); }
    
    .site-header { position: sticky; top: 0; z-index: 100; background: rgba(255, 255, 255, 0.95); backdrop-filter: blur(8px); border-bottom: 1px solid var(--border-color); }
    .nav-wrapper { display: flex; align-items: center; justify-content: space-between; height: 72px; }
    .brand-logo { font-size: 20px; font-weight: 800; color: var(--primary-dark); display: flex; align-items: center; gap: 8px; letter-spacing: -0.5px; }
    .logo-icon { width: 28px; height: 28px; background: var(--accent-teal); border-radius: 4px; display: inline-flex; align-items: center; justify-content: center; color: #fff; font-weight: bold; font-family: var(--mono-font); font-size: 16px; }
    
    .nav-menu { display: flex; list-style: none; gap: 28px; align-items: center; }
    .nav-link { font-size: 15px; font-weight: 500; color: var(--text-main); position: relative; padding: 6px 0; }
    .nav-link:hover, .nav-link.active { color: var(--accent-teal); }
    .nav-link::after { content: ''; position: absolute; bottom: 0; left: 0; width: 0; height: 2px; background: var(--accent-teal); transition: width 0.2s; }
    .nav-link:hover::after { width: 100%; }
    
    .btn { display: inline-flex; align-items: center; justify-content: center; padding: 10px 22px; font-size: 14px; font-weight: 600; border-radius: var(--radius); cursor: pointer; transition: all 0.2s ease; border: 1px solid transparent; }
    .btn-primary { background-color: var(--accent-teal); color: #ffffff; }
    .btn-primary:hover { background-color: #0f766e; }
    .btn-outline { background-color: transparent; border-color: var(--border-color); color: var(--text-main); }
    .btn-outline:hover { border-color: var(--primary-dark); background-color: var(--bg-light); }
    .btn-dark { background-color: var(--primary-dark); color: #ffffff; }
    .btn-dark:hover { background-color: #000000; }
    .btn-amber { background-color: var(--accent-amber); color: #111827; }
    .btn-amber:hover { background-color: #d97706; color: #ffffff; }

    /* Section 1: Hero */
    .hero-section { background: radial-gradient(circle at 80% 20%, rgba(13, 148, 136, 0.08) 0%, transparent 60%), #ffffff; padding: 70px 0 80px; position: relative; border-bottom: 1px solid var(--border-color); }
    .hero-search-box { max-width: 780px; margin: 0 auto 30px; text-align: center; }
    .hero-h1 { font-size: 40px; font-weight: 800; color: var(--primary-dark); line-height: 1.25; margin-bottom: 20px; letter-spacing: -0.8px; }
    .hero-lead { font-size: 16px; color: var(--text-muted); line-height: 1.8; margin-bottom: 30px; }
    .search-mock-bar { display: flex; background: #ffffff; border: 2px solid var(--accent-teal); border-radius: var(--radius); padding: 6px; box-shadow: 0 6px 20px rgba(13, 148, 136, 0.12); margin-bottom: 16px; }
    .search-input { flex: 1; border: none; padding: 12px 18px; outline: none; font-size: 15px; color: var(--text-main); }
    .chips-group { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; align-items: center; font-size: 13px; color: var(--text-muted); }
    .chip { background: var(--bg-light); border: 1px solid var(--border-color); padding: 4px 12px; border-radius: 4px; color: var(--primary-dark); cursor: pointer; transition: 0.2s; }
    .chip:hover { border-color: var(--accent-teal); color: var(--accent-teal); }
    .hero-visual-card { margin-top: 40px; background: #ffffff; border: 1px solid var(--border-color); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow-md); }
    .hero-image-wrap { position: relative; height: 380px; background: #111827; }
    .hero-image-wrap img { width: 100%; height: 100%; object-fit: cover; opacity: 0.85; }
    .hero-overlay-specs { position: absolute; bottom: 0; left: 0; right: 0; background: linear-gradient(to top, rgba(11,15,23,0.95), transparent); padding: 24px; display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; color: #ffffff; }
    .spec-item .num { font-family: var(--mono-font); font-size: 22px; font-weight: 700; color: var(--accent-emerald); }
    .spec-item .label { font-size: 13px; color: #9ca3af; }

    /* Section 2: 关于与技术标准 */
    .grid-2col { display: grid; grid-template-columns: 1fr 1fr; gap: 50px; align-items: center; }
    .spec-list-panel { background: #ffffff; border: 1px solid var(--border-color); border-radius: var(--radius); padding: 28px; box-shadow: var(--shadow-sm); }
    .spec-row { display: flex; justify-content: space-between; padding: 12px 0; border-bottom: 1px dashed var(--border-color); font-size: 14px; }
    .spec-row:last-child { border-bottom: none; }
    .spec-row .k { color: var(--text-muted); }
    .spec-row .v { font-weight: 600; color: var(--primary-dark); font-family: var(--mono-font); }

    /* Section 3: 优势矩阵 (2x3) */
    .grid-3col { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
    .card-box { background: #ffffff; border: 1px solid var(--border-color); border-radius: var(--radius); padding: 30px; box-shadow: var(--shadow-sm); transition: transform 0.2s, box-shadow 0.2s; }
    .card-box:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: #cbd5e1; }
    .card-icon { width: 44px; height: 44px; background: rgba(13, 148, 136, 0.1); border-radius: 4px; display: flex; align-items: center; justify-content: center; font-family: var(--mono-font); font-weight: bold; color: var(--accent-teal); margin-bottom: 20px; border: 1px solid rgba(13, 148, 136, 0.2); }
    .card-title { font-size: 18px; font-weight: 700; color: var(--primary-dark); margin-bottom: 12px; }
    .card-desc { font-size: 14px; color: var(--text-muted); line-height: 1.7; }

    /* Section 4: 热门产品 */
    .product-card { background: #ffffff; border: 1px solid var(--border-color); border-radius: var(--radius); overflow: hidden; display: flex; flex-direction: column; }
    .product-img { height: 200px; background: #e2e8f0; overflow: hidden; }
    .product-img img { width: 100%; height: 100%; object-fit: cover; }
    .product-body { padding: 24px; flex: 1; display: flex; flex-direction: column; }
    .product-body h3 { font-size: 18px; font-weight: 700; margin-bottom: 12px; }
    .product-specs-table { width: 100%; font-size: 13px; margin: 16px 0; border-collapse: collapse; }
    .product-specs-table td { padding: 6px 0; border-bottom: 1px solid var(--border-color); }
    .product-specs-table td:first-child { color: var(--text-muted); width: 40%; }
    .product-specs-table td:last-child { font-weight: 600; font-family: var(--mono-font); text-align: right; }

    /* Section 5: 算法与闭环链路 */
    .pipeline-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin-top: 30px; }
    .pipe-step { background: rgba(255, 255, 255, 0.04); border: 1px solid rgba(255, 255, 255, 0.1); border-radius: var(--radius); padding: 24px; position: relative; }
    .pipe-step .num { font-family: var(--mono-font); font-size: 28px; font-weight: 800; color: var(--accent-emerald); margin-bottom: 10px; }
    .pipe-step h4 { font-size: 16px; color: #ffffff; margin-bottom: 8px; }
    .pipe-step p { font-size: 13px; color: #9ca3af; line-height: 1.6; }

    /* Section 6: 典型案例 */
    .case-row { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: center; margin-bottom: 50px; background: #ffffff; border: 1px solid var(--border-color); border-radius: var(--radius); overflow: hidden; }
    .case-row:last-child { margin-bottom: 0; }
    .case-row.reverse { direction: rtl; }
    .case-row.reverse > * { direction: ltr; }
    .case-img { height: 320px; background: #1f2937; }
    .case-img img { width: 100%; height: 100%; object-fit: cover; }
    .case-info { padding: 36px; }
    .case-info h3 { font-size: 22px; font-weight: 700; margin-bottom: 14px; }
    .case-metric-box { display: flex; gap: 24px; margin-top: 20px; padding-top: 20px; border-top: 1px solid var(--border-color); }
    .case-metric-box .val { font-size: 24px; font-weight: 700; color: var(--accent-teal); font-family: var(--mono-font); }
    .case-metric-box .lbl { font-size: 12px; color: var(--text-muted); }

    /* Section 7: 关键数据统计 */
    .metrics-bar { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
    .metric-card { text-align: center; background: #ffffff; border: 1px solid var(--border-color); padding: 30px 20px; border-radius: var(--radius); }
    .metric-card .digit { font-size: 38px; font-weight: 800; font-family: var(--mono-font); color: var(--primary-dark); margin-bottom: 6px; }
    .metric-card .unit { font-size: 18px; font-weight: 600; color: var(--accent-teal); margin-left: 2px; }
    .metric-card .caption { font-size: 14px; color: var(--text-muted); }

    /* Section 8: 评价墙 */
    .review-card { background: #ffffff; border: 1px solid var(--border-color); border-radius: var(--radius); padding: 26px; }
    .review-quote { font-size: 14px; color: var(--text-main); margin-bottom: 20px; line-height: 1.8; }
    .reviewer-meta { display: flex; align-items: center; gap: 12px; border-top: 1px solid var(--border-color); padding-top: 16px; }
    .avatar-mock { width: 36px; height: 36px; background: var(--bg-light); border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: bold; color: var(--text-muted); font-size: 13px; }
    .reviewer-meta h5 { font-size: 14px; margin-bottom: 2px; }
    .reviewer-meta p { font-size: 12px; color: var(--text-muted); }

    /* Section 9: 资讯摘要 */
    .news-card { background: #ffffff; border: 1px solid var(--border-color); border-radius: var(--radius); padding: 24px; display: flex; flex-direction: column; justify-content: space-between; }
    .news-meta { font-size: 12px; color: var(--text-muted); margin-bottom: 10px; display: flex; justify-content: space-between; }
    .news-title { font-size: 16px; font-weight: 700; margin-bottom: 12px; color: var(--primary-dark); }
    .news-desc { font-size: 13px; color: var(--text-muted); line-height: 1.7; margin-bottom: 18px; }

    /* Section 10: FAQ Accordion */
    .accordion-list { max-width: 900px; margin: 0 auto; display: flex; flex-direction: column; gap: 12px; }
    .faq-item { background: #ffffff; border: 1px solid var(--border-color); border-radius: var(--radius); overflow: hidden; }
    .faq-header { padding: 18px 24px; display: flex; justify-content: space-between; align-items: center; cursor: pointer; font-weight: 600; color: var(--primary-dark); }
    .faq-header:hover { background: var(--bg-light); }
    .faq-icon { font-family: var(--mono-font); font-size: 18px; color: var(--accent-teal); transition: transform 0.2s; }
    .faq-content { padding: 0 24px 20px; font-size: 14px; color: var(--text-muted); line-height: 1.8; display: none; }
    .faq-item.active .faq-content { display: block; }
    .faq-item.active .faq-icon { transform: rotate(45deg); }

    /* Section 11: 联系与选型表单 */
    .contact-wrapper { display: grid; grid-template-columns: 1fr 1.2fr; gap: 50px; background: #ffffff; border: 1px solid var(--border-color); border-radius: var(--radius); padding: 48px; box-shadow: var(--shadow-sm); }
    .contact-info-side h3 { font-size: 24px; margin-bottom: 16px; }
    .info-item { margin-top: 24px; }
    .info-item h4 { font-size: 14px; color: var(--text-muted); margin-bottom: 6px; }
    .info-item p { font-size: 16px; font-weight: 600; color: var(--primary-dark); font-family: var(--mono-font); }
    
    .form-group { margin-bottom: 18px; }
    .form-label { display: block; font-size: 13px; font-weight: 600; margin-bottom: 6px; color: var(--primary-dark); }
    .form-input, .form-select, .form-textarea { width: 100%; padding: 10px 14px; border: 1px solid var(--border-color); border-radius: var(--radius); font-size: 14px; outline: none; transition: border-color 0.2s; }
    .form-input:focus, .form-select:focus, .form-textarea:focus { border-color: var(--accent-teal); }
    .form-row-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }

    /* Section 12: 保障徽章 */
    .guarantee-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
    .guarantee-card { display: flex; align-items: center; gap: 16px; background: #ffffff; border: 1px solid var(--border-color); padding: 20px; border-radius: var(--radius); }
    .g-badge { width: 40px; height: 40px; background: rgba(13, 148, 136, 0.1); border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: bold; color: var(--accent-teal); font-size: 14px; }
    .g-text h4 { font-size: 15px; font-weight: 700; margin-bottom: 2px; }
    .g-text p { font-size: 12px; color: var(--text-muted); }

    /* 全局页脚 */
    .site-footer { background-color: var(--secondary-dark); color: #9ca3af; padding: 60px 0 30px; border-top: 1px solid #1f2937; font-size: 14px; }
    .footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1.5fr; gap: 40px; margin-bottom: 40px; }
    .footer-logo { font-size: 20px; font-weight: 800; color: #ffffff; margin-bottom: 14px; display: flex; align-items: center; gap: 8px; }
    .footer-desc { font-size: 13px; line-height: 1.8; color: #9ca3af; }
    .footer-col h4 { font-size: 15px; font-weight: 600; color: #ffffff; margin-bottom: 18px; }
    .footer-links { list-style: none; display: flex; flex-direction: column; gap: 10px; }
    .footer-links a:hover { color: var(--accent-emerald); }
    .footer-bottom { border-top: 1px solid #1f2937; padding-top: 24px; display: flex; justify-content: space-between; align-items: center; font-size: 12px; }

    /* 移动端与响应式适配 */
    @media (max-width: 1024px) {
      .grid-3col, .pipeline-grid, .metrics-bar, .guarantee-grid { grid-template-columns: repeat(2, 1fr); }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .case-row, .grid-2col, .contact-wrapper { grid-template-columns: 1fr; }
      .hero-overlay-specs { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 768px) {
      .top-utility-bar { display: none; }
      .nav-menu { display: none; }
      .hero-h1 { font-size: 28px; }
      .grid-3col, .pipeline-grid, .metrics-bar, .guarantee-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
      .footer-bottom { flex-direction: column; gap: 10px; text-align: center; }
      .form-row-2 { grid-template-columns: 1fr; }
      .hero-image-wrap { height: 260px; }
      .hero-overlay-specs { position: static; background: #111827; grid-template-columns: 1fr 1fr; }
    }