/* roulang page: index */
:root {
      --primary-red: #FF3B30;
      --primary-hover: #E02E24;
      --accent-orange: #FF5E3A;
      --recovery-green: #10B981;
      --bg-dark: #0F141C;
      --bg-dark-card: #171F2C;
      --bg-light: #F8FAFC;
      --bg-subtle: #F1F5F9;
      --text-dark: #0F172A;
      --text-body: #334155;
      --text-muted: #64748B;
      --border-color: #E2E8F0;
      --border-dark: #273549;
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --radius-xl: 24px;
      --shadow-soft: 0 4px 20px -2px rgba(15, 23, 42, 0.06);
      --shadow-hover: 0 12px 28px -4px rgba(255, 59, 48, 0.12);
      --container-max: 1240px;
    }

    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    html {
      scroll-behavior: smooth;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      color: var(--text-body);
      background-color: #FFFFFF;
      line-height: 1.75;
    }

    body {
      overflow-x: hidden;
      -webkit-font-smoothing: antialiased;
    }

    a {
      color: inherit;
      text-decoration: none;
      transition: all 0.25s ease;
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    .container {
      width: 100%;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 顶部信息条 */
    .top-bar {
      background-color: var(--bg-dark);
      color: #94A3B8;
      font-size: 13px;
      border-bottom: 1px solid var(--border-dark);
      padding: 8px 0;
    }
    .top-bar .container {
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .top-bar-left {
      display: flex;
      align-items: center;
      gap: 16px;
    }
    .top-bar-badge {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      background: rgba(16, 185, 129, 0.15);
      color: var(--recovery-green);
      padding: 2px 8px;
      border-radius: 4px;
      font-size: 12px;
      font-weight: 600;
    }
    .status-dot {
      width: 6px;
      height: 6px;
      background-color: var(--recovery-green);
      border-radius: 50%;
      box-shadow: 0 0 8px var(--recovery-green);
    }

    /* 主导航 */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 1000;
      background-color: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-color);
      box-shadow: 0 2px 10px rgba(0, 0, 0, 0.03);
    }
    .nav-wrapper {
      display: flex;
      justify-content: space-between;
      align-items: center;
      height: 76px;
    }
    .site-logo {
      display: flex;
      align-items: center;
      gap: 12px;
      font-size: 20px;
      font-weight: 800;
      color: var(--text-dark);
      letter-spacing: -0.5px;
    }
    .logo-pulse-box {
      width: 36px;
      height: 36px;
      background: linear-gradient(135deg, var(--primary-red), var(--accent-orange));
      border-radius: 10px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: #FFF;
      box-shadow: 0 4px 12px rgba(255, 59, 48, 0.3);
    }
    .logo-pulse-box svg {
      width: 22px;
      height: 22px;
      fill: none;
      stroke: currentColor;
      stroke-width: 2.2;
      stroke-linecap: round;
      stroke-linejoin: round;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 28px;
      list-style: none;
    }
    .nav-item a {
      font-size: 15px;
      font-weight: 600;
      color: var(--text-dark);
      padding: 8px 4px;
      position: relative;
    }
    .nav-item a:hover {
      color: var(--primary-red);
    }
    .nav-item.active a::after {
      content: "";
      position: absolute;
      bottom: -4px;
      left: 0;
      right: 0;
      height: 2px;
      background-color: var(--primary-red);
      border-radius: 2px;
    }
    .header-actions {
      display: flex;
      align-items: center;
      gap: 16px;
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      font-weight: 600;
      border-radius: var(--radius-md);
      transition: all 0.25s ease;
      cursor: pointer;
      text-align: center;
      border: 1px solid transparent;
      white-space: nowrap;
    }
    .btn-sm {
      padding: 8px 16px;
      font-size: 14px;
    }
    .btn-md {
      padding: 12px 24px;
      font-size: 15px;
    }
    .btn-lg {
      padding: 15px 32px;
      font-size: 16px;
    }
    .btn-primary {
      background-color: var(--primary-red);
      color: #FFFFFF;
      box-shadow: 0 4px 14px rgba(255, 59, 48, 0.25);
    }
    .btn-primary:hover {
      background-color: var(--primary-hover);
      box-shadow: 0 6px 20px rgba(255, 59, 48, 0.35);
      transform: translateY(-2px);
    }
    .btn-outline {
      border-color: var(--border-color);
      background-color: #FFFFFF;
      color: var(--text-dark);
    }
    .btn-outline:hover {
      border-color: var(--text-dark);
      background-color: var(--bg-subtle);
      transform: translateY(-2px);
    }
    .btn-outline-white {
      border-color: rgba(255, 255, 255, 0.3);
      color: #FFFFFF;
      background-color: transparent;
    }
    .btn-outline-white:hover {
      border-color: #FFFFFF;
      background-color: rgba(255, 255, 255, 0.1);
      transform: translateY(-2px);
    }
    .mobile-menu-btn {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      color: var(--text-dark);
      cursor: pointer;
    }

    /* Section 通用规范 */
    section {
      padding: 96px 0;
      position: relative;
    }
    .section-header {
      margin-bottom: 56px;
    }
    .section-header.text-center {
      text-align: center;
      max-width: 800px;
      margin-left: auto;
      margin-right: auto;
    }
    .badge-sub {
      display: inline-block;
      font-size: 13px;
      font-weight: 700;
      letter-spacing: 1px;
      text-transform: uppercase;
      color: var(--primary-red);
      background-color: rgba(255, 59, 48, 0.08);
      padding: 4px 12px;
      border-radius: 20px;
      margin-bottom: 12px;
    }
    .badge-sub.badge-dark {
      background-color: rgba(255, 255, 255, 0.1);
      color: #FF7B60;
    }
    .section-title {
      font-size: 34px;
      font-weight: 800;
      color: var(--text-dark);
      line-height: 1.3;
      letter-spacing: -0.5px;
      margin-bottom: 16px;
    }
    .section-title-dark {
      color: #FFFFFF;
    }
    .section-desc {
      font-size: 16px;
      color: var(--text-muted);
      line-height: 1.7;
    }
    .section-desc-dark {
      color: #94A3B8;
    }

    /* Section 1: Hero（全宽浅色顶栏 + 矮横幅，避免大居中卡） */
    .hero-banner-section {
      background-color: var(--bg-light);
      padding: 64px 0 80px 0;
      border-bottom: 1px solid var(--border-color);
      position: relative;
      overflow: hidden;
    }
    .hero-banner-section::before {
      content: "";
      position: absolute;
      top: -120px;
      right: -80px;
      width: 500px;
      height: 500px;
      background: radial-gradient(circle, rgba(255, 94, 58, 0.08) 0%, rgba(255, 255, 255, 0) 70%);
      border-radius: 50%;
      pointer-events: none;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1.15fr 0.85fr;
      gap: 48px;
      align-items: center;
    }
    .hero-content {
      max-width: 660px;
    }
    .hero-h1 {
      font-size: 42px;
      font-weight: 900;
      line-height: 1.25;
      color: var(--text-dark);
      margin-bottom: 20px;
      letter-spacing: -0.8px;
    }
    .hero-h1 span {
      background: linear-gradient(135deg, var(--primary-red), var(--accent-orange));
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .hero-summary {
      font-size: 16px;
      color: var(--text-body);
      line-height: 1.8;
      margin-bottom: 32px;
    }
    .hero-cta-group {
      display: flex;
      gap: 16px;
      align-items: center;
      flex-wrap: wrap;
    }
    .hero-visual-card {
      background-color: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-lg);
      padding: 24px;
      box-shadow: 0 20px 40px -10px rgba(15, 23, 42, 0.08);
      position: relative;
    }
    .metric-monitor-header {
      display: flex;
      justify-content: space-between;
      align-items: center;
      border-bottom: 1px solid var(--border-color);
      padding-bottom: 16px;
      margin-bottom: 16px;
    }
    .bpm-display-group {
      display: flex;
      align-items: baseline;
      gap: 8px;
    }
    .bpm-val {
      font-size: 54px;
      font-weight: 900;
      color: var(--primary-red);
      line-height: 1;
      font-variant-numeric: tabular-nums;
    }
    .bpm-unit {
      font-size: 16px;
      font-weight: 700;
      color: var(--text-muted);
    }
    .zone-indicator-tag {
      background-color: #FEE2E2;
      color: var(--primary-red);
      font-size: 13px;
      font-weight: 700;
      padding: 6px 14px;
      border-radius: 20px;
    }
    .heart-wave-svg {
      width: 100%;
      height: 90px;
      stroke: var(--primary-red);
      stroke-width: 2.5;
      fill: none;
    }
    .hero-submetrics {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 12px;
      margin-top: 16px;
      padding-top: 16px;
      border-top: 1px solid var(--border-color);
      text-align: center;
    }
    .submetric-title {
      font-size: 12px;
      color: var(--text-muted);
      margin-bottom: 4px;
    }
    .submetric-num {
      font-size: 16px;
      font-weight: 700;
      color: var(--text-dark);
    }

    /* Section 2: 全局关键数据统计条（#stats-bar） */
    .stats-bar-section {
      background-color: var(--bg-dark);
      padding: 48px 0;
      color: #FFFFFF;
      border-top: 1px solid var(--border-dark);
      border-bottom: 1px solid var(--border-dark);
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }
    .stat-item {
      position: relative;
    }
    .stat-item:not(:last-child)::after {
      content: "";
      position: absolute;
      right: 0;
      top: 20%;
      height: 60%;
      width: 1px;
      background-color: var(--border-dark);
    }
    .stat-value {
      font-size: 40px;
      font-weight: 800;
      color: #FFFFFF;
      line-height: 1.1;
      margin-bottom: 8px;
      font-variant-numeric: tabular-nums;
    }
    .stat-value span {
      color: var(--accent-orange);
      font-size: 26px;
    }
    .stat-label {
      font-size: 14px;
      color: #94A3B8;
      font-weight: 500;
    }

    /* Section 3: 运动心率监测平台核心品牌与硬件生态（#about-platform） */
    .about-platform-section {
      background-color: #FFFFFF;
    }
    .dual-feature-layout {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 64px;
      align-items: center;
    }
    .feature-img-wrap {
      position: relative;
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: 0 16px 36px -6px rgba(0, 0, 0, 0.1);
    }
    .feature-img-wrap img {
      width: 100%;
      height: 440px;
      object-fit: cover;
      transition: transform 0.4s ease;
    }
    .feature-img-wrap:hover img {
      transform: scale(1.03);
    }
    .floating-param-pill {
      position: absolute;
      bottom: 24px;
      left: 24px;
      background: rgba(15, 20, 28, 0.85);
      backdrop-filter: blur(8px);
      padding: 12px 20px;
      border-radius: var(--radius-md);
      color: #FFFFFF;
      display: flex;
      align-items: center;
      gap: 12px;
      border: 1px solid rgba(255, 255, 255, 0.15);
    }
    .param-pill-num {
      font-size: 20px;
      font-weight: 800;
      color: var(--accent-orange);
    }
    .param-pill-text {
      font-size: 13px;
      line-height: 1.4;
      color: #CBD5E1;
    }
    .specs-bullet-list {
      list-style: none;
      margin-top: 24px;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .specs-bullet-item {
      display: flex;
      align-items: flex-start;
      gap: 12px;
    }
    .bullet-icon {
      width: 20px;
      height: 20px;
      background-color: rgba(16, 185, 129, 0.15);
      color: var(--recovery-green);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 12px;
      font-weight: 800;
      flex-shrink: 0;
      margin-top: 4px;
    }
    .bullet-content h4 {
      font-size: 16px;
      font-weight: 700;
      color: var(--text-dark);
      margin-bottom: 4px;
    }
    .bullet-content p {
      font-size: 14px;
      color: var(--text-muted);
    }

    /* Section 4: 六大核心优势服务矩阵（#features） */
    .features-section {
      background-color: var(--bg-light);
    }
    .cards-grid-3x2 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .service-card {
      background: #FFFFFF;
      border-radius: var(--radius-md);
      padding: 32px 28px;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-soft);
      transition: all 0.3s ease;
      display: flex;
      flex-direction: column;
      height: 100%;
    }
    .service-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: rgba(255, 59, 48, 0.4);
    }
    .service-icon-box {
      width: 52px;
      height: 52px;
      border-radius: 12px;
      background-color: rgba(255, 59, 48, 0.08);
      color: var(--primary-red);
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
    }
    .service-icon-box svg {
      width: 26px;
      height: 26px;
      fill: none;
      stroke: currentColor;
      stroke-width: 2;
    }
    .service-card h3 {
      font-size: 19px;
      font-weight: 700;
      color: var(--text-dark);
      margin-bottom: 12px;
    }
    .service-card p {
      font-size: 14px;
      color: var(--text-body);
      line-height: 1.7;
    }

    /* Section 5: 三大热门软硬件套件/产品矩阵（#products） */
    .products-section {
      background-color: #FFFFFF;
    }
    .products-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    .product-box {
      background: #FFFFFF;
      border-radius: var(--radius-lg);
      border: 1px solid var(--border-color);
      overflow: hidden;
      display: flex;
      flex-direction: column;
      box-shadow: var(--shadow-soft);
      transition: all 0.3s ease;
    }
    .product-box:hover {
      transform: translateY(-4px);
      box-shadow: 0 16px 36px rgba(15, 23, 42, 0.1);
    }
    .product-box.featured-product {
      border: 2px solid var(--primary-red);
      position: relative;
    }
    .featured-badge-top {
      position: absolute;
      top: 14px;
      right: 14px;
      background: var(--primary-red);
      color: #FFF;
      font-size: 12px;
      font-weight: 700;
      padding: 4px 10px;
      border-radius: 20px;
      z-index: 10;
    }
    .product-thumb-holder {
      height: 200px;
      overflow: hidden;
      background-color: var(--bg-subtle);
    }
    .product-thumb-holder img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.4s ease;
    }
    .product-box:hover .product-thumb-holder img {
      transform: scale(1.05);
    }
    .product-body {
      padding: 28px;
      flex: 1;
      display: flex;
      flex-direction: column;
    }
    .product-body h3 {
      font-size: 20px;
      font-weight: 800;
      color: var(--text-dark);
      margin-bottom: 8px;
    }
    .product-body .product-brief {
      font-size: 14px;
      color: var(--text-muted);
      margin-bottom: 20px;
      line-height: 1.6;
    }
    .product-spec-pills {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
      margin-bottom: 24px;
    }
    .spec-pill {
      font-size: 12px;
      background-color: var(--bg-subtle);
      color: var(--text-body);
      padding: 4px 10px;
      border-radius: 4px;
      font-weight: 600;
    }
    .product-footer-action {
      margin-top: auto;
      padding-top: 16px;
      border-top: 1px solid var(--border-color);
    }

    /* Section 6: 专业心率算法结果对比看板（#comparison） */
    .comparison-section {
      background-color: var(--bg-subtle);
    }
    .comparison-table-wrapper {
      background: #FFFFFF;
      border-radius: var(--radius-lg);
      border: 1px solid var(--border-color);
      overflow-x: auto;
      box-shadow: var(--shadow-soft);
    }
    .comparison-table {
      width: 100%;
      border-collapse: collapse;
      text-align: left;
    }
    .comparison-table th,
    .comparison-table td {
      padding: 20px 24px;
      font-size: 14px;
    }
    .comparison-table thead th {
      background-color: var(--bg-dark);
      color: #FFFFFF;
      font-weight: 700;
      font-size: 15px;
    }
    .comparison-table thead th:nth-child(2) {
      background-color: #1F2937;
      color: #F87171;
      border-bottom: 2px solid var(--primary-red);
    }
    .comparison-table tbody tr {
      border-bottom: 1px solid var(--border-color);
    }
    .comparison-table tbody tr:hover {
      background-color: #F8FAFC;
    }
    .comparison-highlight {
      font-weight: 700;
      color: var(--primary-red);
    }

    /* Section 7: 深色沉浸式技术理念与自研引擎专区（#technology） */
    .technology-dark-section {
      background-color: var(--bg-dark);
      color: #FFFFFF;
      position: relative;
    }
    .tech-layout {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 56px;
      align-items: center;
    }
    .tech-card-showcase {
      background: var(--bg-dark-card);
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-lg);
      padding: 32px;
      position: relative;
    }
    .tech-param-row {
      display: flex;
      justify-content: space-between;
      padding: 16px 0;
      border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    }
    .tech-param-label {
      color: #94A3B8;
      font-size: 14px;
    }
    .tech-param-val {
      color: #FFFFFF;
      font-weight: 700;
      font-size: 15px;
    }

    /* Section 8: 平台技术演进与服务里程碑（#milestones） */
    .milestones-section {
      background-color: #FFFFFF;
    }
    .timeline-container {
      position: relative;
      max-width: 900px;
      margin: 0 auto;
    }
    .timeline-container::after {
      content: '';
      position: absolute;
      width: 2px;
      background: var(--border-color);
      top: 0;
      bottom: 0;
      left: 50%;
      margin-left: -1px;
    }
    .timeline-item {
      padding: 10px 40px;
      position: relative;
      background-color: inherit;
      width: 50%;
      box-sizing: border-box;
    }
    .timeline-item.left {
      left: 0;
      text-align: right;
    }
    .timeline-item.right {
      left: 50%;
      text-align: left;
    }
    .timeline-item::after {
      content: '';
      position: absolute;
      width: 16px;
      height: 16px;
      right: -8px;
      background-color: #FFFFFF;
      border: 4px solid var(--primary-red);
      top: 22px;
      border-radius: 50%;
      z-index: 1;
    }
    .timeline-item.right::after {
      left: -8px;
    }
    .timeline-content {
      padding: 24px;
      background-color: var(--bg-light);
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-soft);
    }
    .timeline-year {
      font-size: 14px;
      font-weight: 800;
      color: var(--primary-red);
      margin-bottom: 6px;
    }
    .timeline-content h3 {
      font-size: 18px;
      color: var(--text-dark);
      margin-bottom: 8px;
    }
    .timeline-content p {
      font-size: 14px;
      color: var(--text-body);
      line-height: 1.6;
    }

    /* Section 9: 典型场景用户故事与实测案例（#case-studies） */
    .case-studies-section {
      background-color: var(--bg-subtle);
    }
    .case-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 30px;
    }
    .case-card {
      background: #FFFFFF;
      border-radius: var(--radius-md);
      overflow: hidden;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-soft);
      display: flex;
      flex-direction: column;
    }
    .case-img-holder {
      height: 200px;
      overflow: hidden;
    }
    .case-img-holder img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }
    .case-body {
      padding: 24px;
      flex: 1;
    }
    .case-tag {
      font-size: 12px;
      color: var(--primary-red);
      font-weight: 700;
      text-transform: uppercase;
      margin-bottom: 8px;
      display: inline-block;
    }
    .case-body h3 {
      font-size: 18px;
      font-weight: 700;
      color: var(--text-dark);
      margin-bottom: 12px;
    }
    .case-body p {
      font-size: 14px;
      color: var(--text-body);
      line-height: 1.6;
    }

    /* Section 10: 运动教练与专业机构用户评价（#testimonials） */
    .testimonials-section {
      background-color: #FFFFFF;
    }
    .testimonials-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 30px;
    }
    .testimonial-card {
      background: var(--bg-light);
      border-radius: var(--radius-md);
      padding: 32px 24px;
      border: 1px solid var(--border-color);
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }
    .stars-rating {
      color: #F59E0B;
      font-size: 16px;
      margin-bottom: 16px;
      letter-spacing: 2px;
    }
    .testimonial-text {
      font-size: 14px;
      color: var(--text-body);
      line-height: 1.7;
      margin-bottom: 24px;
    }
    .author-info {
      display: flex;
      align-items: center;
      gap: 14px;
    }
    .author-avatar {
      width: 46px;
      height: 46px;
      border-radius: 50%;
      background: var(--border-color);
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      color: var(--text-dark);
    }
    .author-name {
      font-size: 15px;
      font-weight: 700;
      color: var(--text-dark);
    }
    .author-role {
      font-size: 13px;
      color: var(--text-muted);
    }

    /* Section 11: 运动生理与心率资讯精选摘要（#news-insights） */
    .news-section {
      background-color: var(--bg-light);
    }
    .news-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 30px;
    }
    .news-card {
      background: #FFFFFF;
      border-radius: var(--radius-md);
      padding: 24px;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-soft);
      display: flex;
      flex-direction: column;
    }
    .news-meta {
      font-size: 13px;
      color: var(--text-muted);
      margin-bottom: 10px;
    }
    .news-card h3 {
      font-size: 18px;
      font-weight: 700;
      color: var(--text-dark);
      margin-bottom: 12px;
      line-height: 1.4;
    }
    .news-card p {
      font-size: 14px;
      color: var(--text-body);
      line-height: 1.6;
      margin-bottom: 20px;
      flex: 1;
    }
    .news-more-btn {
      color: var(--primary-red);
      font-weight: 600;
      font-size: 14px;
      display: inline-flex;
      align-items: center;
      gap: 4px;
    }
    .news-more-btn:hover {
      color: var(--primary-hover);
    }

    /* Section 12: 平台可靠性与合规保障（#guarantee） */
    .guarantee-section {
      background-color: #FFFFFF;
    }
    .guarantee-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .guarantee-box {
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      padding: 28px 20px;
      text-align: center;
      background: var(--bg-subtle);
    }
    .guarantee-icon {
      font-size: 32px;
      margin-bottom: 16px;
      color: var(--primary-red);
    }
    .guarantee-box h3 {
      font-size: 17px;
      font-weight: 700;
      color: var(--text-dark);
      margin-bottom: 8px;
    }
    .guarantee-box p {
      font-size: 13px;
      color: var(--text-muted);
      line-height: 1.6;
    }

    /* Section 13: 运动心率监测平台常见疑问解答（#faq） */
    .faq-section {
      background-color: var(--bg-subtle);
    }
    .faq-container {
      max-width: 820px;
      margin: 0 auto;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .faq-item {
      background: #FFFFFF;
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      overflow: hidden;
    }
    .faq-question {
      padding: 20px 24px;
      font-size: 16px;
      font-weight: 700;
      color: var(--text-dark);
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      user-select: none;
    }
    .faq-icon-arrow {
      font-size: 18px;
      transition: transform 0.3s ease;
      color: var(--text-muted);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.35s ease;
      background-color: #FAFAFA;
      padding: 0 24px;
    }
    .faq-answer p {
      font-size: 14px;
      color: var(--text-body);
      line-height: 1.75;
      padding-bottom: 20px;
    }
    .faq-item.active .faq-icon-arrow {
      transform: rotate(45deg);
      color: var(--primary-red);
    }
    .faq-item.active .faq-answer {
      max-height: 240px;
      padding-top: 10px;
    }

    /* Section 14: 底部意向对接与商业咨询表单 CTA（#contact-cta） */
    .contact-cta-section {
      background-color: var(--bg-dark);
      color: #FFFFFF;
      padding: 80px 0;
    }
    .form-wrapper-box {
      background: var(--bg-dark-card);
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-lg);
      padding: 48px;
      display: grid;
      grid-template-columns: 1fr 1.2fr;
      gap: 56px;
      align-items: center;
    }
    .form-side-info h2 {
      font-size: 30px;
      font-weight: 800;
      color: #FFFFFF;
      margin-bottom: 16px;
      line-height: 1.3;
    }
    .form-side-info p {
      font-size: 15px;
      color: #94A3B8;
      line-height: 1.7;
      margin-bottom: 28px;
    }
    .direct-phone-label {
      font-size: 13px;
      color: #64748B;
      text-transform: uppercase;
      letter-spacing: 1px;
      margin-bottom: 6px;
    }
    .direct-phone-val {
      font-size: 26px;
      font-weight: 800;
      color: var(--accent-orange);
      font-variant-numeric: tabular-nums;
    }
    .contact-form {
      display: flex;
      flex-direction: column;
      gap: 18px;
    }
    .form-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 16px;
    }
    .form-field {
      display: flex;
      flex-direction: column;
      gap: 6px;
    }
    .form-field label {
      font-size: 13px;
      font-weight: 600;
      color: #CBD5E1;
    }
    .form-input,
    .form-select,
    .form-textarea {
      width: 100%;
      padding: 12px 16px;
      background: #0F141C;
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-sm);
      color: #FFFFFF;
      font-size: 14px;
      font-family: inherit;
      outline: none;
      transition: border-color 0.2s ease;
    }
    .form-input:focus,
    .form-select:focus,
    .form-textarea:focus {
      border-color: var(--primary-red);
    }
    .form-textarea {
      height: 90px;
      resize: none;
    }

    /* 页脚 */
    .site-footer {
      background-color: #0B0E14;
      color: #94A3B8;
      padding: 64px 0 32px 0;
      border-top: 1px solid #1E293B;
      font-size: 14px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr 1fr 1.2fr;
      gap: 48px;
      margin-bottom: 48px;
    }
    .footer-col h4 {
      font-size: 16px;
      font-weight: 700;
      color: #FFFFFF;
      margin-bottom: 20px;
    }
    .footer-col p {
      line-height: 1.7;
      margin-bottom: 16px;
    }
    .footer-links-list {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }
    .footer-links-list a:hover {
      color: var(--primary-red);
    }
    .footer-bottom {
      padding-top: 24px;
      border-top: 1px solid #1E293B;
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 16px;
      font-size: 13px;
      color: #64748B;
    }

    /* 响应式样式断点 */
    @media (max-width: 1024px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 40px;
      }
      .dual-feature-layout,
      .tech-layout,
      .form-wrapper-box {
        grid-template-columns: 1fr;
        gap: 40px;
      }
      .cards-grid-3x2,
      .products-grid,
      .case-grid,
      .testimonials-grid,
      .news-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .guarantee-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .footer-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    @media (max-width: 768px) {
      .top-bar {
        display: none;
      }
      .nav-links {
        display: none;
      }
      .mobile-menu-btn {
        display: block;
      }
      .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
      }
      .stat-item:not(:last-child)::after {
        display: none;
      }
      .cards-grid-3x2,
      .products-grid,
      .case-grid,
      .testimonials-grid,
      .news-grid,
      .guarantee-grid,
      .footer-grid {
        grid-template-columns: 1fr;
      }
      .timeline-container::after {
        left: 20px;
      }
      .timeline-item {
        width: 100%;
        padding-left: 50px;
        padding-right: 15px;
        text-align: left !important;
      }
      .timeline-item.right {
        left: 0;
      }
      .timeline-item::after {
        left: 12px !important;
      }
      .form-row {
        grid-template-columns: 1fr;
      }
      .form-wrapper-box {
        padding: 24px;
      }
      .hero-h1 {
        font-size: 32px;
      }
      .section-title {
        font-size: 26px;
      }
    }

    /* 移动端菜单抽屉 */
    .mobile-drawer {
      display: none;
      position: fixed;
      top: 76px;
      left: 0;
      right: 0;
      background: #FFFFFF;
      border-bottom: 1px solid var(--border-color);
      padding: 20px 24px;
      box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
      z-index: 999;
    }
    .mobile-drawer.open {
      display: block;
    }
    .mobile-drawer-links {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    .mobile-drawer-links a {
      font-size: 16px;
      font-weight: 600;
      color: var(--text-dark);
      display: block;
    }