/* roulang page: index */
:root {
      --primary: #0EA5E9;
      --primary-light: rgba(14, 165, 233, 0.08);
      --primary-soft: rgba(14, 165, 233, 0.15);
      --secondary: #1E293B;
      --accent: #F97316;
      --accent-hover: #EA580C;
      --bg: #F8FAFC;
      --white: #FFFFFF;
      --success: #10B981;
      --muted: #94A3B8;
      --text: #1E293B;
      --text-soft: #475569;
      --border: #E2E8F0;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.04), 0 1px 3px rgba(0,0,0,0.02);
      --shadow-hover: 0 12px 32px rgba(0,0,0,0.08), 0 2px 6px rgba(0,0,0,0.04);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 8px;
      --max-width: 1200px;
      --header-height: 70px;
    }

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

    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.7;
      font-size: 16px;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
    }

    a {
      text-decoration: none;
      color: inherit;
    }

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

    button, input, textarea, select {
      font-family: inherit;
    }

    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 20px;
    }

    /* header / nav */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: var(--white);
      border-bottom: 1px solid var(--border);
      z-index: 100;
      height: var(--header-height);
      display: flex;
      align-items: center;
      transition: box-shadow 0.25s ease;
    }

    .site-header.scrolled {
      box-shadow: 0 4px 12px rgba(0,0,0,0.03);
    }

    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }

    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 8px;
      letter-spacing: 0.5px;
    }

    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--primary);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 18px;
    }

    .nav-menu {
      display: flex;
      gap: 32px;
      align-items: center;
    }

    .nav-link {
      font-size: 16px;
      font-weight: 500;
      color: var(--secondary);
      position: relative;
      padding: 8px 0;
      transition: color 0.2s;
    }

    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary);
      transition: width 0.25s ease;
    }

    .nav-link:hover,
    .nav-link.active {
      color: var(--primary);
    }

    .nav-link:hover::after,
    .nav-link.active::after {
      width: 100%;
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
      padding: 4px;
    }

    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--secondary);
      transition: 0.2s;
      display: block;
    }

    .mobile-menu {
      position: fixed;
      top: 0;
      right: -100%;
      width: 280px;
      height: 100vh;
      background: var(--white);
      box-shadow: -4px 0 20px rgba(0,0,0,0.08);
      display: flex;
      flex-direction: column;
      padding: 80px 32px 32px;
      transition: right 0.3s ease;
      z-index: 200;
    }

    .mobile-menu.open {
      right: 0;
    }

    .mobile-close {
      position: absolute;
      top: 24px;
      right: 24px;
      background: none;
      border: none;
      font-size: 28px;
      cursor: pointer;
      color: var(--secondary);
    }

    .mobile-link {
      font-size: 20px;
      font-weight: 500;
      padding: 12px 0;
      border-bottom: 1px solid var(--border);
      color: var(--secondary);
    }

    /* hero */
    .hero {
      padding-top: calc(var(--header-height) + 60px);
      padding-bottom: 80px;
      display: flex;
      align-items: center;
      gap: 60px;
    }

    .hero-text {
      flex: 1 1 50%;
    }

    .hero h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--secondary);
      margin-bottom: 24px;
      letter-spacing: -0.5px;
    }

    .hero .subtitle {
      font-size: 18px;
      color: var(--text-soft);
      margin-bottom: 32px;
    }

    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      cursor: pointer;
      transition: all 0.2s ease;
      border: none;
    }

    .btn-primary {
      background: var(--accent);
      color: white;
    }

    .btn-primary:hover {
      background: var(--accent-hover);
    }

    .btn-secondary {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
    }

    .btn-secondary:hover {
      background: var(--primary-light);
    }

    .hero-image {
      flex: 1 1 50%;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      border-radius: 24px;
      min-height: 380px;
      box-shadow: var(--shadow-card);
    }

    /* sections */
    section {
      padding: 80px 0;
    }

    .section-title {
      font-size: 36px;
      font-weight: 700;
      color: var(--secondary);
      margin-bottom: 16px;
      text-align: center;
    }

    .section-sub {
      font-size: 18px;
      color: var(--text-soft);
      text-align: center;
      margin-bottom: 48px;
    }

    /* 数据看板 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
    }

    .stat-card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 32px 16px;
      text-align: center;
      box-shadow: var(--shadow-card);
    }

    .stat-number {
      font-size: 40px;
      font-weight: 800;
      color: var(--accent);
    }

    .stat-label {
      font-size: 16px;
      color: var(--text-soft);
      margin-top: 8px;
    }

    /* 服务矩阵 */
    .service-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }

    .service-card {
      background: var(--white);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: all 0.25s ease;
    }

    .service-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }

    .service-img {
      height: 160px;
      background-size: cover;
      background-position: center;
      background-color: var(--primary-soft);
    }

    .service-body {
      padding: 24px;
    }

    .service-body h3 {
      font-size: 24px;
      font-weight: 600;
      margin-bottom: 12px;
    }

    .service-body p {
      color: var(--text-soft);
      margin-bottom: 16px;
    }

    .text-link {
      color: var(--primary);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 4px;
    }

    /* 对比 */
    .compare-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: start;
    }

    .compare-box {
      padding: 32px;
      border-radius: var(--radius-card);
      background: var(--white);
    }

    .compare-box.traditional {
      background: #F1F5F9;
      color: var(--muted);
    }

    .compare-box.superior {
      background: var(--white);
      border-left: 6px solid var(--success);
    }

    .compare-box h3 {
      font-size: 24px;
      margin-bottom: 20px;
      font-weight: 600;
    }

    .compare-list {
      list-style: none;
    }

    .compare-list li {
      margin-bottom: 14px;
      display: flex;
      align-items: center;
      gap: 10px;
    }

    /* faq */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }

    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 20px 0;
    }

    .faq-question {
      font-weight: 600;
      font-size: 18px;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }

    .faq-answer {
      margin-top: 12px;
      color: var(--text-soft);
      display: none;
      line-height: 1.7;
    }

    .faq-item.open .faq-answer {
      display: block;
    }

    /* cta */
    .cta-section {
      background: var(--secondary);
      color: white;
    }

    .cta-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }

    .cta-form input,
    .cta-form textarea {
      width: 100%;
      padding: 12px 16px;
      border-radius: var(--radius-input);
      border: 1px solid #CBD5E1;
      margin-bottom: 16px;
      font-size: 16px;
      background: white;
    }

    .cta-form input:focus,
    .cta-form textarea:focus {
      border-color: var(--primary);
      outline: none;
    }

    /* footer */
    .site-footer {
      background: var(--secondary);
      color: var(--muted);
      padding: 60px 0 30px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 40px;
    }

    .footer-brand {
      font-size: 20px;
      font-weight: 700;
      color: white;
    }

    .copyright {
      margin-top: 40px;
      text-align: center;
      font-size: 14px;
    }

    @media (max-width: 1024px) {
      .service-grid { grid-template-columns: repeat(2, 1fr); }
    }

    @media (max-width: 768px) {
      .nav-menu { display: none; }
      .hamburger { display: flex; }
      .hero { flex-direction: column; padding-top: 100px; }
      .hero h1 { font-size: 32px; }
      .hero-image { width: 100%; min-height: 250px; }
      .stats-grid { grid-template-columns: 1fr 1fr; }
      .service-grid { grid-template-columns: 1fr; }
      .compare-row { grid-template-columns: 1fr; }
      .cta-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
      section { padding: 60px 0; }
    }

    @media (max-width: 520px) {
      .stats-grid { grid-template-columns: 1fr; }
    }