/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-hover: #3D5BD9;
      --primary-light: #F0F3FF;
      --secondary: #00B578;
      --warning: #FF9F0A;
      --danger: #FA5151;
      --bg: #F5F6FA;
      --surface: #FFFFFF;
      --text-primary: #1F2329;
      --text-secondary: #86909C;
      --text-disabled: #C9CDD4;
      --border: #E5E6EB;
      --radius-card: 12px;
      --radius-btn: 8px;
      --shadow-sm: 0 2px 12px rgba(0, 0, 0, 0.04);
      --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.06);
      --transition: 0.2s ease;
      --max-width: 1200px;
    }

    * {
      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;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
    }

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
    }

    /* 导航 */
    .header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: var(--surface);
      box-shadow: 0 1px 0 var(--border);
      height: 64px;
      display: flex;
      align-items: center;
    }

    .header .container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }

    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 20px;
      color: var(--text-primary);
      letter-spacing: -0.3px;
    }

    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--primary);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-weight: 600;
      font-size: 18px;
    }

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

    .nav-link {
      font-size: 15px;
      color: var(--text-secondary);
      font-weight: 500;
      transition: color var(--transition);
      position: relative;
    }

    .nav-link:hover,
    .nav-link:focus-visible {
      color: var(--primary);
    }

    .nav-link.active {
      color: var(--primary);
    }

    .mobile-nav {
      display: none;
    }

    /* 汉堡按钮 */
    .hamburger {
      display: none;
      flex-direction: column;
      justify-content: space-between;
      width: 24px;
      height: 18px;
      background: transparent;
      border: none;
      padding: 0;
    }

    .hamburger span {
      width: 100%;
      height: 2px;
      background: var(--text-primary);
      border-radius: 2px;
      transition: var(--transition);
    }

    /* 底部移动导航 */
    .bottom-nav {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      right: 0;
      background: var(--surface);
      border-top: 1px solid var(--border);
      z-index: 60;
      padding: 8px 16px;
      justify-content: space-around;
      align-items: center;
      height: 64px;
    }

    .bottom-nav-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
      font-size: 12px;
      color: var(--text-secondary);
      transition: color var(--transition);
    }

    .bottom-nav-item i {
      font-size: 20px;
    }

    .bottom-nav-item.active {
      color: var(--primary);
    }

    /* 按钮系统 */
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 12px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: background var(--transition), transform var(--transition);
      white-space: nowrap;
    }

    .btn-primary:hover {
      background: var(--primary-hover);
    }

    .btn-outline {
      background: transparent;
      color: var(--primary);
      border: 1.5px solid var(--primary);
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      transition: all var(--transition);
    }

    .btn-outline:hover {
      background: var(--primary-light);
    }

    .btn-white {
      background: white;
      color: var(--primary);
      border: 1.5px solid white;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      transition: all var(--transition);
    }

    .btn-white:hover {
      background: rgba(255,255,255,0.9);
    }

    /* Hero */
    .hero {
      background: var(--surface);
      padding: 60px 0;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
    }

    .hero-content {
      flex: 1;
    }

    .hero h1 {
      font-size: 36px;
      font-weight: 700;
      line-height: 1.3;
      color: var(--text-primary);
      margin-bottom: 16px;
      letter-spacing: -0.5px;
    }

    .hero-sub {
      font-size: 16px;
      color: var(--text-secondary);
      margin-bottom: 28px;
      line-height: 1.6;
    }

    .hero-image {
      flex: 1;
      display: flex;
      justify-content: center;
    }

    .hero-image img {
      max-height: 360px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-md);
    }

    /* 通用板块 */
    .section {
      padding: 64px 0;
    }

    .section-title {
      font-size: 28px;
      font-weight: 700;
      text-align: center;
      margin-bottom: 12px;
      color: var(--text-primary);
    }

    .section-sub {
      text-align: center;
      color: var(--text-secondary);
      margin-bottom: 48px;
      font-size: 16px;
    }

    .grid-2 {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }

    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }

    .card {
      background: var(--surface);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      transition: all var(--transition);
    }

    .card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-2px);
    }

    .feature-icon {
      width: 48px;
      height: 48px;
      background: var(--primary-light);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--primary);
      font-size: 24px;
      margin-bottom: 16px;
    }

    .stat-number {
      font-size: 34px;
      font-weight: 700;
      color: var(--secondary);
      line-height: 1.2;
    }

    .testimonial-card {
      background: var(--surface);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      position: relative;
    }

    .testimonial-quote {
      font-size: 28px;
      color: var(--primary);
      line-height: 1;
      margin-bottom: 12px;
    }

    .avatar {
      width: 48px;
      height: 48px;
      border-radius: 50%;
      background: #ddd;
      margin-right: 12px;
    }

    /* FAQ */
    .faq-item {
      background: var(--surface);
      border-radius: var(--radius-card);
      margin-bottom: 12px;
      box-shadow: var(--shadow-sm);
      overflow: hidden;
    }

    .faq-question {
      width: 100%;
      padding: 18px 24px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 16px;
      background: transparent;
      border: none;
      color: var(--text-primary);
      cursor: pointer;
      transition: background var(--transition);
    }

    .faq-question:hover {
      background: var(--primary-light);
    }

    .faq-answer {
      padding: 0 24px 18px;
      color: var(--text-secondary);
      font-size: 15px;
      display: none;
    }

    .faq-item.open .faq-answer {
      display: block;
    }

    .faq-item.open .faq-question {
      background: var(--primary-light);
      color: var(--primary);
    }

    .faq-icon {
      font-size: 20px;
      transition: transform 0.2s;
    }

    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }

    /* CTA 横幅 */
    .cta-banner {
      background: var(--primary);
      border-radius: var(--radius-card);
      padding: 48px 24px;
      text-align: center;
      color: white;
    }

    .cta-banner h2 {
      font-size: 28px;
      font-weight: 700;
      margin-bottom: 16px;
    }

    .footer {
      background: var(--bg);
      padding: 40px 0 20px;
      border-top: 1px solid var(--border);
      color: var(--text-secondary);
      font-size: 14px;
    }

    .footer-grid {
      display: flex;
      justify-content: space-between;
      align-items: flex-start;
      flex-wrap: wrap;
      gap: 24px;
      margin-bottom: 24px;
    }

    .footer-links {
      display: flex;
      gap: 24px;
    }

    .footer-links a {
      color: var(--text-secondary);
      transition: color var(--transition);
    }

    .footer-links a:hover {
      color: var(--primary);
    }

    .copyright {
      text-align: center;
      padding-top: 16px;
      border-top: 1px solid var(--border);
      color: var(--text-disabled);
    }

    @media (max-width: 1024px) {
      .grid-4 {
        grid-template-columns: repeat(2, 1fr);
      }
      .hero h1 {
        font-size: 30px;
      }
    }

    @media (max-width: 768px) {
      .header .nav-desktop {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .bottom-nav {
        display: flex;
      }
      .container {
        padding: 0 16px;
      }
      .hero-grid {
        flex-direction: column;
        text-align: center;
      }
      .hero h1 {
        font-size: 26px;
      }
      .grid-2, .grid-3, .grid-4 {
        grid-template-columns: 1fr;
      }
      .section {
        padding: 48px 0;
      }
      .footer-grid {
        flex-direction: column;
        align-items: center;
        text-align: center;
      }
      .footer-links {
        justify-content: center;
      }
      body {
        padding-bottom: 80px;
      }
    }