/* roulang page: index */
:root {
      --bg-titanium: #0F1115;
      --bg-card: #161A22;
      --bg-card-hover: #1C222D;
      --bg-surface: #F8FAFC;
      --primary: #00D1B2;
      --primary-hover: #06B6D4;
      --text-main: #FFFFFF;
      --text-muted: #94A3B8;
      --text-dark: #0F172A;
      --border-subtle: rgba(148, 163, 184, 0.16);
      --border-glow: rgba(0, 209, 178, 0.4);
      --radius-sm: 6px;
      --radius-md: 10px;
      --radius-lg: 16px;
      --font-stack: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      --font-mono: "DIN Alternate", "Inter", monospace, system-ui;
    }

    * { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; font-family: var(--font-stack); background-color: var(--bg-titanium); color: var(--text-main); }
    body { line-height: 1.75; font-size: 15px; -webkit-font-smoothing: antialiased; overflow-x: hidden; }
    a { color: inherit; text-decoration: none; transition: all 0.25s ease; }
    img { max-width: 100%; height: auto; display: block; }
    button, input, textarea, select { font-family: inherit; }

    .container { max-width: 1280px; margin: 0 auto; padding: 0 24px; }
    .text-cyan { color: var(--primary); }
    .mono-num { font-family: var(--font-mono); }
    
    /* 顶部双行导航 */
    header.site-header { position: sticky; top: 0; z-index: 100; backdrop-filter: blur(14px); background: rgba(15, 17, 21, 0.88); border-bottom: 1px solid var(--border-subtle); }
    .top-bar { border-bottom: 1px solid rgba(148, 163, 184, 0.1); font-size: 12px; color: var(--text-muted); padding: 6px 0; }
    .top-bar-inner { display: flex; justify-content: space-between; align-items: center; }
    .top-bar-tags span { display: inline-flex; align-items: center; margin-right: 18px; }
    .top-bar-tags span::before { content: ""; width: 6px; height: 6px; background: var(--primary); border-radius: 50%; margin-right: 6px; display: inline-block; }
    
    .nav-main { display: flex; justify-content: space-between; align-items: center; height: 72px; }
    .brand-logo { font-size: 20px; font-weight: 700; letter-spacing: -0.5px; display: flex; align-items: center; gap: 10px; }
    .brand-logo-mark { width: 32px; height: 32px; background: linear-gradient(135deg, var(--primary), var(--primary-hover)); border-radius: var(--radius-sm); display: flex; align-items: center; justify-content: center; font-weight: 800; color: #000; font-size: 16px; }
    .nav-links { display: flex; list-style: none; gap: 28px; }
    .nav-links a { color: #E2E8F0; font-size: 15px; font-weight: 500; }
    .nav-links a:hover { color: var(--primary); }
    .nav-cta-btn { background: var(--primary); color: #071614; font-weight: 600; padding: 9px 20px; border-radius: 999px; font-size: 14px; display: inline-flex; align-items: center; gap: 6px; border: none; cursor: pointer; transition: all 0.2s ease; }
    .nav-cta-btn:hover { background: #38e2cb; box-shadow: 0 0 16px var(--border-glow); }
    
    .mobile-menu-btn { display: none; background: none; border: 1px solid var(--border-subtle); color: #FFF; width: 44px; height: 44px; border-radius: 8px; cursor: pointer; }
    .mobile-drawer { display: none; background: var(--bg-card); padding: 20px; border-bottom: 1px solid var(--border-subtle); }
    .mobile-drawer a { display: block; padding: 12px 0; border-bottom: 1px solid rgba(148, 163, 184, 0.08); font-size: 15px; }

    /* 通用Section */
    section { padding: 88px 0; position: relative; }
    .section-head { margin-bottom: 48px; }
    .section-tag { display: inline-block; font-size: 12px; font-weight: 600; letter-spacing: 1px; text-transform: uppercase; color: var(--primary); margin-bottom: 10px; background: rgba(0, 209, 178, 0.1); padding: 4px 12px; border-radius: 999px; border: 1px solid rgba(0, 209, 178, 0.2); }
    .section-title { font-size: 32px; font-weight: 700; line-height: 1.35; color: #F8FAFC; margin-bottom: 16px; }
    .section-desc { font-size: 15px; color: var(--text-muted); max-width: 820px; line-height: 1.8; }
    .card-base { background: var(--bg-card); border: 1px solid var(--border-subtle); border-radius: var(--radius-md); padding: 28px; transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease; }
    .card-base:hover { border-color: var(--border-glow); transform: translateY(-4px); box-shadow: 0 12px 30px rgba(0,0,0,0.4); }

    /* 板块 1: Hero（蓝图要求：文档帮助中心/工程检索型 Hero） */
    .hero-sec { padding: 90px 0 70px; background: radial-gradient(circle at 50% -20%, rgba(0, 209, 178, 0.15) 0%, rgba(15, 17, 21, 0) 70%), linear-gradient(180deg, rgba(15,17,21,0.85) 0%, #0F1115 100%), url('/assets/images/172b6714dfbce4cb.webp') center/cover no-repeat; text-align: center; }
    .hero-inner { max-width: 860px; margin: 0 auto; }
    .hero-h1 { font-size: 42px; font-weight: 800; line-height: 1.25; margin-bottom: 20px; letter-spacing: -0.5px; }
    .hero-p { font-size: 16px; color: #CBD5E1; line-height: 1.85; margin-bottom: 36px; }
    .hero-search-box { position: relative; max-width: 640px; margin: 0 auto 24px; }
    .hero-search-box input { width: 100%; height: 54px; background: rgba(22, 26, 34, 0.95); border: 1px solid rgba(0, 209, 178, 0.4); border-radius: 999px; padding: 0 140px 0 24px; font-size: 15px; color: #FFF; outline: none; }
    .hero-search-box input:focus { border-color: var(--primary); box-shadow: 0 0 14px var(--border-glow); }
    .hero-search-box button { position: absolute; right: 6px; top: 6px; height: 42px; background: var(--primary); color: #000; font-weight: 600; border: none; border-radius: 999px; padding: 0 20px; cursor: pointer; }
    .hero-chips { display: flex; flex-wrap: wrap; justify-content: center; gap: 10px; }
    .hero-chips a { font-size: 13px; color: var(--text-muted); background: rgba(255, 255, 255, 0.05); padding: 5px 14px; border-radius: 999px; border: 1px solid rgba(255, 255, 255, 0.08); }
    .hero-chips a:hover { color: var(--primary); border-color: var(--primary); }

    /* 板块 2: 客户案例/量产车型落地实践 */
    .case-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
    .case-card { overflow: hidden; border-radius: var(--radius-md); background: var(--bg-card); border: 1px solid var(--border-subtle); display: flex; flex-direction: column; }
    .case-card-img { height: 210px; overflow: hidden; position: relative; }
    .case-card-img img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.4s ease; }
    .case-card:hover .case-card-img img { transform: scale(1.05); }
    .case-card-body { padding: 24px; flex: 1; display: flex; flex-direction: column; }
    .case-badge { font-size: 12px; color: var(--primary); background: rgba(0, 209, 178, 0.1); padding: 3px 8px; border-radius: 4px; display: inline-block; margin-bottom: 12px; align-self: flex-start; }
    .case-card-body h3 { font-size: 18px; margin-bottom: 10px; font-weight: 600; }
    .case-card-body p { font-size: 14px; color: var(--text-muted); line-height: 1.7; flex: 1; }
    .case-param { display: flex; justify-content: space-between; border-top: 1px solid rgba(148, 163, 184, 0.1); padding-top: 14px; margin-top: 16px; font-size: 13px; }

    /* 板块 3: 结果数据与看板条 */
    .metrics-row { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
    .metric-card { background: linear-gradient(180deg, #1A1F2B 0%, #12151B 100%); border: 1px solid var(--border-subtle); border-radius: var(--radius-md); padding: 28px; text-align: center; }
    .metric-val { font-size: 38px; font-weight: 800; color: var(--primary); line-height: 1.2; margin-bottom: 6px; }
    .metric-label { font-size: 14px; color: #E2E8F0; font-weight: 600; margin-bottom: 6px; }
    .metric-sub { font-size: 12px; color: var(--text-muted); }

    /* 板块 4: 前后对比与代际更迭 */
    .compare-container { display: grid; grid-template-columns: 1fr 1fr; gap: 28px; }
    .compare-panel { border-radius: var(--radius-md); padding: 32px; border: 1px solid var(--border-subtle); }
    .compare-panel.legacy { background: rgba(22, 26, 34, 0.6); }
    .compare-panel.modern { background: linear-gradient(145deg, rgba(0, 209, 178, 0.06), #161A22); border-color: rgba(0, 209, 178, 0.35); }
    .compare-panel h3 { font-size: 20px; margin-bottom: 18px; display: flex; align-items: center; justify-content: space-between; }
    .compare-list { list-style: none; display: flex; flex-direction: column; gap: 14px; }
    .compare-list li { display: flex; justify-content: space-between; font-size: 14px; padding-bottom: 10px; border-bottom: 1px dashed rgba(148, 163, 184, 0.12); }
    .compare-list li span.val { font-weight: 600; font-family: var(--font-mono); }

    /* 板块 5: 方法说明与三电架构解构 */
    .method-grid { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 40px; align-items: center; }
    .method-img { border-radius: var(--radius-md); overflow: hidden; border: 1px solid var(--border-subtle); height: 380px; }
    .method-img img { width: 100%; height: 100%; object-fit: cover; }
    .method-steps { display: flex; flex-direction: column; gap: 20px; }
    .step-item { display: flex; gap: 16px; }
    .step-num { width: 36px; height: 36px; border-radius: 50%; background: rgba(0,209,178,0.15); color: var(--primary); display: flex; align-items: center; justify-content: center; font-weight: 700; flex-shrink: 0; font-family: var(--font-mono); }
    .step-content h4 { font-size: 16px; margin-bottom: 4px; color: #F1F5F9; }
    .step-content p { font-size: 14px; color: var(--text-muted); line-height: 1.6; }

    /* 板块 6: 卖点三连 */
    .triple-points { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
    .point-card { background: var(--bg-card); border: 1px solid var(--border-subtle); border-radius: var(--radius-md); padding: 32px 24px; position: relative; }
    .point-card::before { content: ""; position: absolute; top: 0; left: 24px; right: 24px; height: 2px; background: linear-gradient(90deg, var(--primary), transparent); }
    .point-card h3 { font-size: 18px; margin-bottom: 10px; color: #FFF; }
    .point-card p { font-size: 14px; color: var(--text-muted); line-height: 1.7; }

    /* 板块 7: 平台选型与车型开发方案（Tab轻交互） */
    .tabs-wrapper { margin-top: 24px; }
    .tab-headers { display: flex; gap: 12px; margin-bottom: 24px; border-bottom: 1px solid var(--border-subtle); padding-bottom: 12px; }
    .tab-btn { background: transparent; border: 1px solid var(--border-subtle); color: var(--text-muted); padding: 10px 24px; border-radius: var(--radius-sm); font-size: 14px; font-weight: 600; cursor: pointer; transition: all 0.2s ease; }
    .tab-btn.active { background: rgba(0, 209, 178, 0.15); color: var(--primary); border-color: var(--primary); }
    .tab-content { display: none; }
    .tab-content.active { display: grid; grid-template-columns: 1fr 1fr; gap: 32px; background: var(--bg-card); border-radius: var(--radius-md); border: 1px solid var(--border-subtle); padding: 32px; }
    .tab-specs-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 16px; margin-top: 20px; }
    .spec-item { background: rgba(15, 17, 21, 0.6); padding: 12px 16px; border-radius: var(--radius-sm); border-left: 2px solid var(--primary); }
    .spec-item .k { font-size: 12px; color: var(--text-muted); }
    .spec-item .v { font-size: 15px; font-weight: 600; font-family: var(--font-mono); color: #FFF; }

    /* 板块 8: 产业落地里程碑时间轴 */
    .timeline-wrap { position: relative; padding: 20px 0; }
    .timeline-wrap::before { content: ""; position: absolute; top: 50%; left: 0; right: 0; height: 2px; background: rgba(148, 163, 184, 0.15); transform: translateY(-50%); }
    .timeline-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; position: relative; }
    .timeline-node { background: var(--bg-card); border: 1px solid var(--border-subtle); border-radius: var(--radius-md); padding: 22px; position: relative; }
    .timeline-node::after { content: ""; position: absolute; top: -14px; left: 24px; width: 10px; height: 10px; border-radius: 50%; background: var(--primary); box-shadow: 0 0 10px var(--primary); }
    .timeline-year { font-size: 12px; font-weight: 700; color: var(--primary); font-family: var(--font-mono); margin-bottom: 6px; }
    .timeline-node h4 { font-size: 15px; margin-bottom: 8px; color: #FFF; }
    .timeline-node p { font-size: 13px; color: var(--text-muted); line-height: 1.6; }

    /* 板块 9: 资讯摘要网格 */
    .news-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
    .news-card { background: var(--bg-card); border: 1px solid var(--border-subtle); border-radius: var(--radius-md); overflow: hidden; display: flex; flex-direction: column; }
    .news-card-img { height: 160px; overflow: hidden; }
    .news-card-img img { width: 100%; height: 100%; object-fit: cover; }
    .news-body { padding: 20px; flex: 1; display: flex; flex-direction: column; }
    .news-meta { display: flex; justify-content: space-between; font-size: 12px; color: var(--text-muted); margin-bottom: 10px; }
    .news-title { font-size: 16px; font-weight: 600; color: #FFF; margin-bottom: 8px; line-height: 1.4; }
    .news-desc { font-size: 13px; color: var(--text-muted); line-height: 1.65; flex: 1; }

    /* 板块 10: 整车安全与全生命周期保障 */
    .sec-assurance { background: linear-gradient(180deg, #12151B 0%, #0F1115 100%); }
    .audit-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
    .audit-card { background: rgba(22, 26, 34, 0.8); border: 1px solid var(--border-subtle); border-radius: var(--radius-md); padding: 22px; }
    .audit-icon { font-size: 20px; color: var(--primary); margin-bottom: 12px; font-weight: bold; }
    .audit-card h4 { font-size: 15px; color: #FFF; margin-bottom: 6px; }
    .audit-card p { font-size: 13px; color: var(--text-muted); line-height: 1.6; }

    /* 板块 11: 异议拆解与常见考量 */
    .faq-accordion { max-width: 900px; margin: 0 auto; display: flex; flex-direction: column; gap: 12px; }
    .faq-item { background: var(--bg-card); border: 1px solid var(--border-subtle); border-radius: var(--radius-sm); overflow: hidden; }
    .faq-head { width: 100%; padding: 18px 24px; display: flex; justify-content: space-between; align-items: center; background: none; border: none; color: #FFF; font-size: 15px; font-weight: 600; text-align: left; cursor: pointer; }
    .faq-head:hover { color: var(--primary); }
    .faq-chevron { font-size: 14px; transition: transform 0.25s ease; color: var(--primary); }
    .faq-body { max-height: 0; overflow: hidden; transition: max-height 0.3s ease; padding: 0 24px; color: var(--text-muted); font-size: 14px; line-height: 1.75; }
    .faq-item.active .faq-chevron { transform: rotate(180deg); }
    .faq-item.active .faq-body { padding-bottom: 18px; max-height: 200px; }

    /* 板块 12: 咨询与白皮书申领表单（收口行动） */
    .conversion-box { background: linear-gradient(135deg, #161A22 0%, #111827 100%); border: 1px solid rgba(0, 209, 178, 0.3); border-radius: var(--radius-lg); padding: 48px; display: grid; grid-template-columns: 1fr 1fr; gap: 48px; }
    .conversion-intro h3 { font-size: 26px; font-weight: 700; margin-bottom: 16px; color: #FFF; }
    .conversion-intro p { font-size: 14px; color: var(--text-muted); line-height: 1.8; margin-bottom: 24px; }
    .contact-spec-list { display: flex; flex-direction: column; gap: 12px; font-size: 13px; color: #CBD5E1; }
    .form-group { margin-bottom: 16px; }
    .form-group label { display: block; font-size: 13px; color: #94A3B8; margin-bottom: 6px; }
    .form-control { width: 100%; background: #0F1115; border: 1px solid var(--border-subtle); border-radius: var(--radius-sm); height: 44px; padding: 0 14px; color: #FFF; font-size: 14px; outline: none; }
    .form-control:focus { border-color: var(--primary); }
    textarea.form-control { height: 96px; padding: 10px 14px; resize: vertical; }
    .submit-btn { width: 100%; height: 48px; background: var(--primary); border: none; border-radius: var(--radius-sm); color: #000; font-size: 15px; font-weight: 700; cursor: pointer; transition: all 0.2s ease; }
    .submit-btn:hover { background: #32e3cc; box-shadow: 0 0 16px var(--border-glow); }

    /* 浮动行动条（吸底） */
    .sticky-bar { position: fixed; bottom: 0; left: 0; right: 0; background: rgba(15, 17, 21, 0.94); border-top: 1px solid var(--border-glow); padding: 12px 24px; z-index: 90; backdrop-filter: blur(10px); transform: translateY(100%); transition: transform 0.3s ease; }
    .sticky-bar.visible { transform: translateY(0); }
    .sticky-bar-inner { max-width: 1280px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; }

    /* 页脚 */
    footer.site-footer { background: #0A0C0F; border-top: 1px solid var(--border-subtle); padding: 64px 0 32px; font-size: 13px; color: var(--text-muted); }
    .footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1fr; gap: 40px; margin-bottom: 48px; }
    .footer-col h5 { font-size: 14px; color: #FFF; margin-bottom: 16px; font-weight: 600; }
    .footer-links { list-style: none; display: flex; flex-direction: column; gap: 10px; }
    .footer-links a:hover { color: var(--primary); }
    .footer-bottom { border-top: 1px solid rgba(148, 163, 184, 0.1); padding-top: 24px; text-align: center; font-size: 12px; }

    /* 响应式断点 */
    @media (max-width: 1024px) {
      .nav-links, .nav-cta-btn { display: none; }
      .mobile-menu-btn { display: flex; align-items: center; justify-content: center; }
      .metrics-row, .audit-grid { grid-template-columns: repeat(2, 1fr); }
      .timeline-grid { grid-template-columns: repeat(2, 1fr); }
      .timeline-wrap::before { display: none; }
      .conversion-box { grid-template-columns: 1fr; gap: 32px; padding: 32px; }
    }
    @media (max-width: 768px) {
      .case-grid, .triple-points, .news-grid { grid-template-columns: 1fr; }
      .compare-container { grid-template-columns: 1fr; }
      .method-grid { grid-template-columns: 1fr; }
      .method-img { height: 240px; }
      .hero-h1 { font-size: 28px; }
      .hero-search-box button { position: static; width: 100%; margin-top: 8px; }
      .hero-search-box input { padding-right: 20px; }
      .tab-content.active { grid-template-columns: 1fr; padding: 20px; }
      .tab-headers { overflow-x: auto; padding-bottom: 8px; }
      .tab-btn { white-space: nowrap; }
      .footer-grid { grid-template-columns: 1fr 1fr; gap: 24px; }
      .top-bar-tags span:nth-child(2) { display: none; }
      .sticky-bar-inner { flex-direction: column; gap: 8px; text-align: center; }
    }
    @media (max-width: 520px) {
      .metrics-row, .audit-grid, .timeline-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
    }