/* roulang page: index */
:root {
      --primary: #1A5F7A;
      --primary-dark: #0B2A3B;
      --accent: #F4A261;
      --accent-hover: #E08A4A;
      --bg: #FAFBFD;
      --card-bg: #FFFFFF;
      --text-primary: #0B2A3B;
      --text-body: #3A4F5C;
      --text-muted: #7B8E9B;
      --border: #E8EDF2;
      --footer-bg: #0B2A3B;
      --success: #2A9D8F;
      --hover-link: #E76F51;
      --radius-card: 12px;
      --radius-btn: 8px;
      --shadow-sm: 0 1px 3px rgba(11,42,59,0.04), 0 1px 2px rgba(11,42,59,0.03);
      --shadow-hover: 0 8px 24px rgba(11,42,59,0.08), 0 2px 6px rgba(11,42,59,0.04);
      --transition: 0.25s ease;
      --font-title: 'Noto Sans SC', 'Alibaba PuHuiTi', 'PingFang SC', 'Microsoft YaHei', sans-serif;
      --font-body: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', system-ui, sans-serif;
      --font-number: 'DIN Alternate', 'Noto Sans SC', sans-serif;
      --container: 1280px;
    }

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

    body {
      font-family: var(--font-body);
      background-color: var(--bg);
      color: var(--text-body);
      line-height: 1.8;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
    }

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

    h1, h2, h3, h4 {
      font-family: var(--font-title);
      color: var(--text-primary);
      font-weight: 700;
    }

    h1 { font-size: 48px; line-height: 1.2; font-weight: 800; }
    h2 { font-size: 36px; line-height: 1.3; margin-bottom: 16px; }
    h3 { font-size: 24px; line-height: 1.4; font-weight: 600; }
    h4 { font-size: 20px; line-height: 1.5; font-weight: 500; }

    a {
      color: var(--primary);
      text-decoration: none;
      transition: color var(--transition), border-color var(--transition);
      border-bottom: 1px solid transparent;
    }

    a:hover {
      color: var(--hover-link);
      border-bottom-color: var(--hover-link);
    }

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

    button, .btn {
      cursor: pointer;
      font-family: var(--font-title);
      font-weight: 600;
      transition: all var(--transition);
      border: none;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      font-size: 16px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
    }

    .btn-primary {
      background-color: var(--accent);
      color: #FFFFFF;
      box-shadow: 0 4px 12px rgba(244, 162, 97, 0.3);
    }
    .btn-primary:hover {
      background-color: var(--accent-hover);
      transform: scale(1.02);
      color: #FFFFFF;
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover {
      background: var(--primary);
      color: #fff;
    }

    /* Header & Navigation */
    #header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.95);
      backdrop-filter: blur(12px);
      box-shadow: 0 1px 0 rgba(11,42,59,0.06);
      z-index: 100;
      padding: 16px 0;
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: var(--container);
      margin: 0 auto;
      padding: 0 24px;
    }

    .logo {
      font-family: var(--font-title);
      font-size: 24px;
      font-weight: 800;
      color: var(--primary-dark);
      letter-spacing: 2px;
      border-bottom: none;
    }
    .logo span {
      color: var(--accent);
    }

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

    .nav-links a {
      font-weight: 500;
      color: var(--text-body);
      border-bottom: 2px solid transparent;
      padding: 4px 0;
    }

    .nav-links a:hover, .nav-links a.active {
      color: var(--accent);
      border-bottom-color: var(--accent);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--primary-dark);
      transition: var(--transition);
    }

    .mobile-menu {
      display: none;
      position: fixed;
      top: 70px;
      left: 0;
      width: 100%;
      background: var(--bg);
      flex-direction: column;
      padding: 32px 24px;
      gap: 24px;
      box-shadow: var(--shadow-hover);
      z-index: 99;
    }
    .mobile-menu a {
      font-size: 20px;
      font-weight: 600;
    }

    /* Hero */
    #hero {
      padding: 140px 0 100px;
      background: var(--bg);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1.1fr 0.9fr;
      gap: 48px;
      align-items: center;
    }
    .hero-left h1 {
      margin-bottom: 24px;
      color: var(--primary-dark);
    }
    .hero-sub {
      font-size: 18px;
      color: var(--text-body);
      margin-bottom: 32px;
      max-width: 550px;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      margin-bottom: 40px;
    }
    .stats {
      display: flex;
      gap: 32px;
    }
    .stat-item {
      font-family: var(--font-number);
      font-weight: 700;
      font-size: 28px;
      color: var(--primary-dark);
    }
    .stat-item small {
      display: block;
      font-family: var(--font-body);
      font-size: 14px;
      color: var(--text-muted);
      font-weight: 400;
      margin-top: 4px;
    }
    .hero-right img {
      border-radius: var(--radius-card);
      box-shadow: 16px 16px 0 rgba(26,95,122,0.1);
      width: 100%;
      height: auto;
    }

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

    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      margin-bottom: 8px;
    }
    .section-title p {
      color: var(--text-muted);
      max-width: 600px;
      margin: 0 auto;
    }

    /* features grid */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--card-bg);
      padding: 32px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .feature-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-2px);
    }
    .feature-icon {
      font-size: 40px;
      color: var(--primary);
      margin-bottom: 20px;
    }
    .feature-card h4 {
      margin-bottom: 12px;
    }

    /* services waterfall */
    .services-waterfall {
      display: flex;
      flex-direction: column;
      gap: 48px;
    }
    .service-row {
      display: flex;
      gap: 24px;
      align-items: center;
    }
    .service-row.reverse {
      flex-direction: row-reverse;
    }
    .service-img {
      flex: 1;
      border-radius: var(--radius-card);
      overflow: hidden;
    }
    .service-img img {
      width: 100%;
      height: 280px;
      object-fit: cover;
      border-radius: 8px;
    }
    .service-text {
      flex: 1;
      padding: 0 16px;
    }
    .service-text h3 {
      margin-bottom: 12px;
    }

    /* cases */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .case-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      overflow: hidden;
      transition: var(--transition);
    }
    .case-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-2px);
    }
    .case-img {
      height: 200px;
      object-fit: cover;
      width: 100%;
    }
    .case-body {
      padding: 24px;
    }
    .case-body h4 {
      margin-bottom: 12px;
    }
    .case-meta {
      display: flex;
      gap: 16px;
      font-size: 14px;
      color: var(--text-muted);
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 16px 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 18px;
      color: var(--primary-dark);
      cursor: pointer;
      background: none;
      border: none;
      width: 100%;
      text-align: left;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-body);
      padding-right: 24px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 12px;
    }

    /* Contact */
    .contact-wrapper {
      background: #EFF5F9;
      border-radius: var(--radius-card);
      padding: 48px;
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
    }
    .contact-form input, .contact-form textarea {
      width: 100%;
      padding: 12px 16px;
      border: 1px solid var(--border);
      border-radius: 8px;
      margin-bottom: 16px;
      font-family: var(--font-body);
    }
    .contact-info p {
      margin-bottom: 12px;
    }

    /* Footer */
    #footer {
      background: var(--footer-bg);
      color: #B0C4D1;
      padding: 48px 0 24px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    .footer-col h4 {
      color: #fff;
      margin-bottom: 16px;
    }
    .footer-col a {
      color: #B0C4D1;
      display: block;
      margin-bottom: 8px;
    }
    .copyright {
      margin-top: 40px;
      text-align: center;
      border-top: 1px solid rgba(255,255,255,0.1);
      padding-top: 24px;
      font-size: 14px;
    }

    @media (max-width: 1024px) {
      h1 { font-size: 40px; }
      .hero-grid { grid-template-columns: 1fr; }
      .hero-right { order: -1; }
      .features-grid { grid-template-columns: repeat(2, 1fr); }
      .cases-grid { grid-template-columns: repeat(2, 1fr); }
      .footer-grid { grid-template-columns: repeat(2, 1fr); }
    }

    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .mobile-menu.active { display: flex; }
      .features-grid, .cases-grid { grid-template-columns: 1fr; }
      .service-row, .service-row.reverse { flex-direction: column; }
      .contact-wrapper { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
      .stats { flex-wrap: wrap; gap: 20px; }
    }