/* roulang page: index */
:root {
      --primary-orange: #FF5C00;
      --primary-deep: #0A1A2F;
      --accent-green: #00C853;
      --accent-gold: #FFB300;
      --bg-light: #F5F6FA;
      --bg-white: #FFFFFF;
      --text-dark: #1F2329;
      --text-muted: #86909C;
      --text-light: #B0B8C1;
      --white: #FFFFFF;
      --radius-card: 12px;
      --radius-btn: 8px;
      --shadow-card: 0 4px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.08);
      --font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --max-width: 1200px;
      --header-height: 64px;
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    body {
      font-family: var(--font-family);
      background-color: var(--bg-light);
      color: var(--text-dark);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
    }
    
    button, .btn {
      cursor: pointer;
      border: none;
      font-family: inherit;
    }
    
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    
    /* Header / Navigation */
    .header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: var(--bg-white);
      height: var(--header-height);
      display: flex;
      align-items: center;
      box-shadow: 0 1px 4px rgba(0,0,0,0.04);
    }
    
    .header .container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    
    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--primary-deep);
      letter-spacing: 1px;
      white-space: nowrap;
      display: flex;
      align-items: center;
    }
    .logo span {
      color: var(--primary-orange);
      margin-left: 4px;
    }
    
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    
    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: var(--text-dark);
      position: relative;
      padding: 4px 0;
      transition: color 0.2s;
    }
    
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary-orange);
      transition: width 0.2s ease;
    }
    
    .nav-links a:hover {
      color: var(--primary-orange);
    }
    
    .nav-links a:hover::after {
      width: 100%;
    }
    
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
      width: 28px;
      cursor: pointer;
    }
    .hamburger span {
      display: block;
      height: 2px;
      background: var(--primary-deep);
      border-radius: 4px;
      transition: 0.2s;
    }
    
    /* Mobile menu */
    .mobile-menu {
      display: none;
      position: fixed;
      top: var(--header-height);
      left: 0;
      width: 100%;
      background: var(--bg-white);
      box-shadow: 0 8px 20px rgba(0,0,0,0.06);
      flex-direction: column;
      padding: 24px 0;
      gap: 20px;
      text-align: center;
      z-index: 99;
    }
    .mobile-menu a {
      font-size: 18px;
      font-weight: 500;
      color: var(--text-dark);
      padding: 8px 0;
      display: block;
    }
    .mobile-menu a:hover {
      color: var(--primary-orange);
    }
    
    /* Hero */
    .hero {
      background: var(--bg-light);
      position: relative;
      overflow: hidden;
      padding: 80px 0;
    }
    .hero::before {
      content: '';
      position: absolute;
      top: -50%;
      right: -20%;
      width: 600px;
      height: 600px;
      background: radial-gradient(circle, rgba(255,92,0,0.06) 0%, transparent 70%);
      border-radius: 50%;
    }
    .hero .container {
      display: flex;
      align-items: center;
      gap: 48px;
      position: relative;
      z-index: 2;
    }
    .hero-text {
      flex: 1;
    }
    .hero-text h1 {
      font-size: 36px;
      font-weight: 700;
      line-height: 1.3;
      color: var(--primary-deep);
      margin-bottom: 16px;
    }
    .hero-text p {
      font-size: 16px;
      color: var(--text-muted);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary-orange);
      color: var(--white);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      transition: all 0.2s ease;
      display: inline-block;
    }
    .btn-primary:hover {
      background: #E05200;
      box-shadow: 0 8px 18px rgba(255,92,0,0.25);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary-orange);
      color: var(--primary-orange);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      transition: all 0.2s ease;
      display: inline-block;
    }
    .btn-outline:hover {
      background: #FFF3EB;
    }
    .hero-image {
      flex: 1;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      min-height: 320px;
      border-radius: 20px;
      box-shadow: var(--shadow-hover);
    }
    
    /* Sections */
    section {
      padding: 80px 0;
    }
    
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      font-size: 28px;
      font-weight: 600;
      color: var(--text-dark);
      margin-bottom: 12px;
    }
    .section-title p {
      color: var(--text-muted);
      font-size: 16px;
      max-width: 600px;
      margin: 0 auto;
    }
    
    /* Advantages */
    .advantages-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .advantage-card {
      background: var(--bg-white);
      padding: 32px 24px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      text-align: center;
      transition: all 0.2s;
    }
    .advantage-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .icon-circle {
      width: 64px;
      height: 64px;
      background: #FFF3EB;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 16px;
      color: var(--primary-orange);
      font-size: 28px;
    }
    
    /* Services */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .service-card {
      background: var(--bg-white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      overflow: hidden;
      transition: all 0.2s;
    }
    .service-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-2px);
    }
    .service-img {
      height: 180px;
      background-size: cover;
      background-position: center;
    }
    .service-content {
      padding: 20px;
    }
    
    /* Data */
    .data-section {
      background: var(--primary-deep);
      color: var(--white);
    }
    .data-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      text-align: center;
    }
    .data-item .number {
      font-size: 36px;
      font-weight: 700;
      color: var(--white);
    }
    .data-item .label {
      font-size: 14px;
      color: var(--text-light);
      margin-top: 8px;
    }
    
    /* Cases */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .case-card {
      background: var(--bg-white);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: 0.2s;
    }
    .case-card:hover {
      box-shadow: var(--shadow-hover);
    }
    .case-img {
      height: 200px;
      background-size: cover;
      transition: transform 0.3s;
    }
    .case-card:hover .case-img {
      transform: scale(1.02);
    }
    
    /* Solution steps */
    .steps {
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .step {
      text-align: center;
      flex: 1;
    }
    .step-circle {
      width: 48px;
      height: 48px;
      background: var(--primary-orange);
      color: white;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      margin: 0 auto 12px;
    }
    
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      background: var(--bg-white);
      border-radius: var(--radius-card);
      margin-bottom: 12px;
      box-shadow: var(--shadow-card);
    }
    .faq-question {
      padding: 18px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    
    /* CTA */
    .cta-block {
      background: var(--bg-light);
      text-align: center;
    }
    
    /* Footer */
    .footer {
      background: var(--primary-deep);
      color: var(--white);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    
    @media (max-width: 1024px) {
      .services-grid { grid-template-columns: repeat(2, 1fr); }
      .cases-grid { grid-template-columns: repeat(2, 1fr); }
    }
    
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero .container {
        flex-direction: column;
      }
      .hero-text h1 { font-size: 28px; }
      .advantages-grid,
      .services-grid,
      .data-grid,
      .cases-grid {
        grid-template-columns: 1fr;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
      .steps {
        flex-direction: column;
        gap: 24px;
      }
      section {
        padding: 60px 0;
      }
    }