/* roulang page: index */
/* 设计变量与全局预设 */
    :root {
      --primary: #4E6EF2;
      --primary-hover: #3A5CE4;
      --secondary-green: #00B578;
      --warning-orange: #FF9F0A;
      --error-red: #FA5151;
      --bg-page: #F5F6FA;
      --bg-card: #FFFFFF;
      --bg-dark: #1F2329;
      --text-primary: #1F2329;
      --text-secondary: #86909C;
      --text-light: #C0C6CF;
      --text-white: #FFFFFF;
      --border-light: #E5E8EF;
      --shadow-card: 0 2px 8px rgba(31, 35, 41, 0.04);
      --shadow-card-hover: 0 4px 16px rgba(31, 35, 41, 0.08);
      --shadow-nav: 0 1px 4px rgba(31, 35, 41, 0.06);
      --shadow-btn: 0 4px 12px rgba(78, 110, 242, 0.3);
      --radius-card: 12px;
      --radius-btn: 50px;
      --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --transition: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    }
    
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    
    html {
      scroll-behavior: smooth;
    }
    
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-page);
      color: var(--text-primary);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    
    img {
      max-width: 100%;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }
    
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    
    @media (max-width: 767px) {
      .container {
        padding: 0 16px;
      }
    }
    
    /* 导航样式 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 64px;
      background: transparent;
      z-index: 1000;
      transition: background var(--transition), box-shadow var(--transition);
      display: flex;
      align-items: center;
    }
    
    .navbar.scrolled {
      background: rgba(255,255,255,0.98);
      backdrop-filter: blur(8px);
      box-shadow: var(--shadow-nav);
    }
    
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    
    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--text-primary);
      display: flex;
      align-items: center;
      gap: 8px;
      letter-spacing: 0.5px;
    }
    
    .logo-icon {
      width: 28px;
      height: 28px;
      background: var(--primary);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 18px;
    }
    
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    
    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: var(--text-primary);
      padding: 8px 0;
      border-bottom: 2px solid transparent;
      transition: color var(--transition), border-color var(--transition);
    }
    
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }
    
    .btn-primary-nav {
      background: var(--primary);
      color: white;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 500;
      font-size: 15px;
      transition: background var(--transition), box-shadow var(--transition);
      white-space: nowrap;
    }
    
    .btn-primary-nav:hover {
      background: var(--primary-hover);
      box-shadow: var(--shadow-btn);
    }
    
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
      padding: 4px;
    }
    
    .hamburger span {
      display: block;
      width: 24px;
      height: 2px;
      background: var(--text-primary);
      transition: all var(--transition);
    }
    
    @media (max-width: 1024px) {
      .nav-links {
        display: none;
        position: fixed;
        top: 64px;
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: 24px;
        gap: 20px;
        box-shadow: 0 8px 20px rgba(0,0,0,0.06);
        border-top: 1px solid var(--border-light);
      }
      .nav-links.active {
        display: flex;
      }
      .hamburger {
        display: flex;
      }
    }
    
    /* 板块间距 */
    section {
      padding: 100px 0;
    }
    
    @media (max-width: 767px) {
      section {
        padding: 80px 0;
      }
    }
    
    /* Hero 首屏 */
    .hero-bg {
      background: linear-gradient(135deg, #F5F6FA 0%, #E8F0FE 100%);
      min-height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
    }
    
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    
    .hero-title {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--text-primary);
      margin-bottom: 24px;
    }
    
    .hero-sub {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 40px;
      line-height: 1.6;
    }
    
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    
    .btn-hero-primary {
      background: var(--primary);
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      transition: background var(--transition), box-shadow var(--transition);
      display: inline-block;
    }
    
    .btn-hero-primary:hover {
      background: var(--primary-hover);
      box-shadow: var(--shadow-btn);
    }
    
    .btn-hero-secondary {
      background: transparent;
      color: var(--primary);
      border: 1px solid var(--primary);
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      transition: all var(--transition);
    }
    
    .btn-hero-secondary:hover {
      background: #E8F0FE;
    }
    
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: 32px;
      height: 420px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.08);
    }
    
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 40px;
        text-align: center;
      }
      .hero-title {
        font-size: 36px;
      }
      .hero-image {
        height: 280px;
      }
      .hero-actions {
        justify-content: center;
      }
    }
    
    /* 卡片通用 */
    .card {
      background: var(--bg-card);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-card);
      transition: transform var(--transition), box-shadow var(--transition);
    }
    
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    
    .section-title {
      font-size: 36px;
      font-weight: 600;
      line-height: 1.3;
      margin-bottom: 16px;
      color: var(--text-primary);
      text-align: center;
    }
    
    .section-sub {
      font-size: 16px;
      color: var(--text-secondary);
      text-align: center;
      max-width: 700px;
      margin: 0 auto 48px;
    }
    
    /* 优势网格 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    
    @media (max-width: 768px) {
      .features-grid {
        grid-template-columns: 1fr;
      }
    }
    
    .icon-bg {
      width: 56px;
      height: 56px;
      background: #E8F0FE;
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 24px;
    }
    
    /* 服务左右交替 */
    .service-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
      margin-bottom: 100px;
    }
    
    .service-row:last-child {
      margin-bottom: 0;
    }
    
    .service-img {
      background-size: cover;
      background-position: center;
      border-radius: 24px;
      height: 360px;
    }
    
    @media (max-width: 768px) {
      .service-row {
        grid-template-columns: 1fr;
        gap: 32px;
        margin-bottom: 80px;
      }
      .service-img {
        height: 260px;
      }
      .section-title {
        font-size: 28px;
      }
    }
    
    /* 场景卡片 */
    .scenarios-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    
    .scenario-card img {
      border-radius: 12px 12px 0 0;
      height: 200px;
      object-fit: cover;
      width: 100%;
    }
    
    @media (max-width: 768px) {
      .scenarios-grid {
        grid-template-columns: 1fr;
      }
    }
    
    /* 案例轮播 */
    .cases-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 16px;
      scroll-snap-type: x mandatory;
    }
    
    .case-card {
      min-width: 320px;
      background: white;
      border-radius: 16px;
      padding: 24px;
      box-shadow: var(--shadow-card);
      display: flex;
      flex-direction: column;
      gap: 16px;
    }
    
    .data-highlight {
      font-size: 32px;
      font-weight: 700;
      color: var(--secondary-green);
    }
    
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
      cursor: pointer;
    }
    
    .faq-question {
      font-weight: 600;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-secondary);
      font-size: 15px;
    }
    
    .faq-answer.open {
      max-height: 200px;
      margin-top: 12px;
    }
    
    /* CTA */
    .cta-block {
      background: linear-gradient(135deg, #E8F0FE 0%, #F5F6FA 100%);
      text-align: center;
    }
    
    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      color: var(--text-secondary);
    }
    
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }