/* roulang page: index */
:root {
      --primary: #0AAD6C;
      --primary-deep: #1A7A4C;
      --primary-hover: #088F5A;
      --success: #00B578;
      --warning: #FF9F0A;
      --error: #FA5151;
      --bg: #F5F6FA;
      --surface: #FFFFFF;
      --dark-bg: #1F2329;
      --text-primary: #1F2329;
      --text-secondary: #4E5969;
      --text-muted: #86909C;
      --border: #E5E6EB;
      --shadow-card: 0 4px 12px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.06);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.08), 0 2px 6px rgba(0,0,0,0.05);
      --radius-sm: 8px;
      --radius: 12px;
      --radius-lg: 16px;
      --transition: 200ms ease-out;
      --max-width: 1200px;
      --header-height: 72px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
      background-color: var(--bg);
      color: var(--text-primary);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
      overflow-x: hidden;
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
    }
    a {
      color: inherit;
      text-decoration: none;
    }
    img {
      max-width: 100%;
      display: block;
      height: auto;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: var(--transition);
      font-weight: 600;
      border-radius: var(--radius-sm);
      font-size: 16px;
      padding: 12px 28px;
    }
    .btn-primary {
      background-color: var(--primary);
      color: #fff;
      box-shadow: 0 2px 8px rgba(10,173,108,0.25);
    }
    .btn-primary:hover {
      background-color: var(--primary-hover);
      box-shadow: 0 4px 14px rgba(10,173,108,0.35);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover {
      background: rgba(10,173,108,0.05);
    }
    .btn-ghost {
      border: 1.5px solid #fff;
      color: #fff;
      background: transparent;
    }
    .btn-ghost:hover {
      background: rgba(255,255,255,0.1);
    }
    .section-title {
      font-size: 32px;
      font-weight: 700;
      line-height: 1.3;
      margin-bottom: 16px;
      color: var(--text-primary);
    }
    .section-subtitle {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 48px;
    }
    @media (max-width: 768px) {
      .section-title {
        font-size: 26px;
      }
      .section-subtitle {
        font-size: 16px;
        margin-bottom: 32px;
      }
    }
    /* Header & Navigation */
    #header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(0,0,0,0.04);
      height: var(--header-height);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      font-size: 24px;
      font-weight: 800;
      color: var(--text-primary);
      letter-spacing: -0.5px;
    }
    .logo span {
      color: var(--primary);
    }
    .nav-links {
      display: flex;
      gap: 28px;
      list-style: none;
    }
    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: var(--text-muted);
      padding: 8px 0;
      position: relative;
      transition: color 0.2s;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
    }
    .nav-links a.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
    }
    .nav-cta {
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-primary);
      border-radius: 2px;
      transition: 0.2s;
    }
    @media (max-width: 1024px) {
      .nav-links {
        gap: 18px;
      }
    }
    @media (max-width: 768px) {
      .nav-links, .nav-cta .btn {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .nav-container {
        padding: 0 16px;
      }
      .mobile-menu {
        position: fixed;
        top: var(--header-height);
        left: 0;
        right: 0;
        background: rgba(255,255,255,0.98);
        backdrop-filter: blur(16px);
        flex-direction: column;
        padding: 24px;
        gap: 20px;
        border-bottom: 1px solid var(--border);
        display: none;
        z-index: 99;
      }
      .mobile-menu.open {
        display: flex;
      }
      .mobile-menu a {
        font-size: 18px;
        font-weight: 500;
        color: var(--text-primary);
        padding: 8px 0;
      }
    }
    /* Hero */
    #home {
      padding: 80px 0 100px;
      background: linear-gradient(135deg, #E8F5EE 0%, #F5F6FA 100%);
      position: relative;
      overflow: hidden;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .hero-content h1 {
      font-size: 48px;
      font-weight: 800;
      line-height: 1.2;
      margin-bottom: 20px;
      color: var(--text-primary);
    }
    .hero-content h1 span {
      color: var(--primary);
    }
    .hero-content p {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-visual {
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      border-radius: var(--radius-lg);
      min-height: 380px;
      background-color: #E0E7EF;
      box-shadow: var(--shadow-card);
      position: relative;
    }
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 40px;
      }
      .hero-content h1 {
        font-size: 32px;
      }
      .hero-visual {
        min-height: 260px;
      }
      #home {
        padding: 60px 0 80px;
      }
    }
    /* Sections common */
    section {
      padding: 80px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
    }
    /* Features */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--surface);
      border-radius: var(--radius);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      transition: all var(--transition);
    }
    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .feature-icon {
      width: 48px;
      height: 48px;
      background: rgba(10,173,108,0.1);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 24px;
    }
    .feature-card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 12px;
    }
    .feature-card p {
      color: var(--text-muted);
      font-size: 15px;
    }
    @media (max-width: 768px) {
      .features-grid {
        grid-template-columns: 1fr;
      }
    }
    /* Services */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .service-card {
      background: var(--surface);
      border-radius: var(--radius);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: all var(--transition);
    }
    .service-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .service-img {
      height: 200px;
      background-color: #E8ECF1;
      background-size: cover;
      background-position: center;
    }
    .service-body {
      padding: 20px 24px 24px;
    }
    .service-body h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .service-body p {
      font-size: 14px;
      color: var(--text-muted);
      margin-bottom: 16px;
    }
    .tags {
      display: flex;
      gap: 8px;
      flex-wrap: wrap;
    }
    .tag {
      background: rgba(10,173,108,0.1);
      color: var(--primary-deep);
      font-size: 12px;
      padding: 4px 12px;
      border-radius: 20px;
      font-weight: 500;
    }
    @media (max-width: 1024px) {
      .services-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 640px) {
      .services-grid {
        grid-template-columns: 1fr;
      }
    }
    /* Scenarios */
    .scenario-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
      margin-bottom: 64px;
    }
    .scenario-img {
      background-color: #DCE3EB;
      border-radius: var(--radius);
      height: 280px;
      background-size: cover;
      background-position: center;
    }
    .scenario-text h3 {
      font-size: 24px;
      font-weight: 700;
      margin-bottom: 16px;
    }
    .scenario-text p {
      color: var(--text-secondary);
    }
    @media (max-width: 768px) {
      .scenario-row {
        grid-template-columns: 1fr;
        gap: 24px;
      }
    }
    /* Cases */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .case-stat {
      background: var(--surface);
      border-radius: var(--radius);
      padding: 32px 20px;
      text-align: center;
      box-shadow: var(--shadow-card);
    }
    .case-number {
      font-size: 44px;
      font-weight: 800;
      color: var(--primary);
    }
    .case-label {
      font-size: 14px;
      color: var(--text-muted);
      margin-top: 8px;
    }
    @media (max-width: 768px) {
      .cases-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    /* FAQ */
    .faq-list {
      display: flex;
      flex-direction: column;
      gap: 12px;
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: var(--surface);
      border-radius: var(--radius-sm);
      box-shadow: var(--shadow-card);
      overflow: hidden;
    }
    .faq-question {
      width: 100%;
      background: none;
      border: none;
      padding: 20px 24px;
      font-size: 18px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--text-primary);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      padding: 0 24px;
      color: var(--text-secondary);
      font-size: 15px;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding: 0 24px 20px;
    }
    .faq-icon {
      font-size: 22px;
      font-weight: 300;
      color: var(--primary);
    }
    /* CTA */
    #cta {
      background: var(--dark-bg);
      text-align: center;
      padding: 80px 0;
    }
    #cta h2 {
      color: #fff;
      font-size: 36px;
    }
    #cta p {
      color: rgba(255,255,255,0.7);
      margin: 16px 0 32px;
    }
    /* Footer */
    #footer {
      background: var(--dark-bg);
      color: #ccc;
      padding: 60px 0 30px;
      font-size: 14px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 40px;
    }
    .footer-brand p {
      margin-top: 12px;
      color: var(--text-muted);
    }
    .footer-links h4 {
      color: #fff;
      margin-bottom: 16px;
    }
    .footer-links a {
      display: block;
      color: var(--text-muted);
      margin-bottom: 10px;
    }
    .footer-links a:hover {
      color: #fff;
    }
    .copyright {
      border-top: 1px solid rgba(255,255,255,0.08);
      padding-top: 24px;
      text-align: center;
      color: var(--text-muted);
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }