/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-hover: #3A5CD9;
      --accent: #FF6B35;
      --accent-hover: #e55a2b;
      --success: #00B578;
      --warning: #FF9F0A;
      --danger: #FA5151;
      --bg: #F5F6FA;
      --surface: #FFFFFF;
      --text-primary: #1F2329;
      --text-secondary: #86909C;
      --border-light: #E5E8EF;
      --shadow-sm: 0 2px 8px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.02);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08), 0 2px 6px rgba(0,0,0,0.04);
      --radius-lg: 12px;
      --radius-pill: 50px;
      --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --transition: 200ms ease-out;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text-primary);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }

    button {
      font-family: inherit;
      cursor: pointer;
      border: none;
      background: none;
      transition: all var(--transition);
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
    }

    /* 导航 */
    .header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(8px);
      -webkit-backdrop-filter: blur(8px);
      box-shadow: 0 1px 0 transparent;
      transition: box-shadow 0.3s;
      height: 64px;
      display: flex;
      align-items: center;
    }
    .header.scrolled {
      box-shadow: var(--shadow-sm);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 1px;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo span {
      color: var(--text-primary);
      font-weight: 400;
      font-size: 14px;
      margin-left: 4px;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-link {
      font-size: 16px;
      font-weight: 500;
      color: var(--text-primary);
      padding: 8px 0;
      border-bottom: 2px solid transparent;
      transition: color var(--transition), border-color var(--transition);
    }
    .nav-link:hover,
    .nav-link.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }
    .btn-nav {
      background: var(--primary);
      color: #fff;
      padding: 8px 20px;
      border-radius: var(--radius-pill);
      font-weight: 600;
      font-size: 15px;
      margin-left: 8px;
    }
    .btn-nav:hover {
      background: var(--primary-hover);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      padding: 8px;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-primary);
      border-radius: 4px;
      transition: all 0.3s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 64px;
      left: 0;
      width: 100%;
      height: calc(100vh - 64px);
      background: var(--surface);
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 24px;
      z-index: 99;
      transform: translateX(100%);
      transition: transform 0.3s ease;
    }
    .mobile-menu.open {
      transform: translateX(0);
      display: flex;
    }
    .mobile-menu .nav-link {
      font-size: 20px;
    }
    @media (max-width: 768px) {
      .nav-menu {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .header {
        height: 56px;
      }
    }

    /* Hero */
    .hero {
      background: var(--bg);
      padding: 80px 0;
      position: relative;
      overflow: hidden;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-text {
      flex: 1;
      z-index: 2;
    }
    .hero h1 {
      font-size: 36px;
      font-weight: 700;
      line-height: 1.3;
      color: var(--text-primary);
      margin-bottom: 20px;
    }
    .hero-sub {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 36px;
      line-height: 1.6;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: #fff;
      padding: 14px 32px;
      border-radius: var(--radius-pill);
      font-weight: 600;
      font-size: 16px;
      box-shadow: 0 4px 10px rgba(78,110,242,0.3);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-1px);
    }
    .btn-outline-accent {
      background: transparent;
      border: 1.5px solid var(--accent);
      color: var(--accent);
      padding: 14px 32px;
      border-radius: var(--radius-pill);
      font-weight: 600;
      font-size: 16px;
    }
    .btn-outline-accent:hover {
      background: var(--accent);
      color: #fff;
    }
    .hero-visual {
      flex: 1;
      position: relative;
      display: flex;
      justify-content: center;
      align-items: center;
    }
    .hero-backdrop {
      position: absolute;
      width: 450px;
      height: 450px;
      background: rgba(78,110,242,0.05);
      border-radius: 50%;
      top: 50%;
      left: 50%;
      transform: translate(-50%, -50%);
      z-index: 0;
    }
    .hero-img {
      position: relative;
      z-index: 1;
      border-radius: 24px;
      overflow: hidden;
      box-shadow: var(--shadow-md);
      max-width: 100%;
    }
    @media (max-width: 1024px) {
      .hero-grid {
        flex-direction: column;
        text-align: center;
      }
      .hero-buttons {
        justify-content: center;
      }
      .hero h1 {
        font-size: 28px;
      }
      .hero-visual {
        margin-top: 40px;
      }
      .hero-backdrop {
        width: 300px;
        height: 300px;
      }
    }

    section {
      padding: 80px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 48px 0;
      }
    }
    .section-title {
      font-size: 28px;
      font-weight: 600;
      margin-bottom: 16px;
      color: var(--text-primary);
    }
    .section-sub {
      font-size: 16px;
      color: var(--text-secondary);
      margin-bottom: 48px;
    }

    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .card {
      background: var(--surface);
      border-radius: var(--radius-lg);
      padding: 32px 24px;
      box-shadow: var(--shadow-sm);
      transition: all 250ms ease-out;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .icon-circle {
      width: 48px;
      height: 48px;
      background: #EEF1FE;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 24px;
    }
    .card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 12px;
    }
    .card p {
      font-size: 14px;
      color: var(--text-secondary);
    }
    .service-img {
      height: 180px;
      object-fit: cover;
      border-radius: 12px 12px 0 0;
      background: #ddd;
    }
    .link-arrow {
      color: var(--primary);
      font-weight: 500;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      margin-top: 16px;
      font-size: 15px;
    }
    .link-arrow:hover {
      text-decoration: underline;
    }

    .case-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 8px;
      scroll-snap-type: x mandatory;
    }
    .case-card {
      min-width: 280px;
      flex: 0 0 auto;
      background: var(--surface);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-sm);
      scroll-snap-align: start;
      transition: 0.2s;
    }
    .case-card img {
      height: 180px;
      width: 100%;
      object-fit: cover;
    }
    .case-body {
      padding: 20px;
    }
    .case-stat {
      font-size: 24px;
      font-weight: 700;
      color: var(--accent);
    }

    .timeline {
      display: flex;
      justify-content: space-between;
      position: relative;
      margin-top: 40px;
    }
    .timeline::before {
      content: "";
      position: absolute;
      top: 24px;
      left: 0;
      width: 100%;
      height: 2px;
      background: #E5E8EF;
      z-index: 0;
    }
    .step {
      background: var(--surface);
      border-radius: var(--radius-lg);
      padding: 24px;
      text-align: center;
      z-index: 1;
      width: 22%;
      box-shadow: var(--shadow-sm);
    }
    .step-number {
      font-size: 32px;
      font-weight: 700;
      color: rgba(78,110,242,0.2);
    }
    @media (max-width: 768px) {
      .grid-3, .timeline {
        display: flex;
        flex-direction: column;
        gap: 16px;
      }
      .step {
        width: 100%;
      }
      .timeline::before {
        display: none;
      }
    }

    .faq-item {
      background: var(--surface);
      border-radius: var(--radius-lg);
      margin-bottom: 8px;
      overflow: hidden;
    }
    .faq-question {
      padding: 16px 20px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease-out;
      background: #F8F9FC;
      padding: 0 20px;
      font-size: 14px;
    }
    .faq-item.open .faq-answer {
      padding: 16px 20px;
    }

    .cta-block {
      background: linear-gradient(105deg, #EEF1FE 0%, #F5F6FA 100%);
      text-align: center;
      padding: 80px 0;
    }

    .footer {
      background: #FFFFFF;
      border-top: 1px solid var(--border-light);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer-col h4 {
      margin-bottom: 16px;
      font-weight: 600;
    }
    .footer-col a, .footer-col p {
      font-size: 14px;
      color: var(--text-secondary);
      margin-bottom: 8px;
      display: block;
    }
    .footer-bottom {
      text-align: center;
      margin-top: 40px;
      font-size: 14px;
      color: var(--text-secondary);
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }