/* roulang page: index */
:root {
      --primary: #0F172A;
      --brand-cyan: #0E7490;
      --brand-accent: #F59E0B;
      --bg-light: #F8FAFC;
      --bg-dark: #0A0F1D;
      --text-main: #1E293B;
      --text-muted: #64748B;
      --card-border: rgba(226, 232, 240, 0.9);
      --card-radius: 1rem;
      --shadow-soft: 0 10px 25px -5px rgba(15, 23, 42, 0.05), 0 8px 10px -6px rgba(15, 23, 42, 0.03);
    }
    body {
      font-family: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
      line-height: 1.8;
      color: var(--text-main);
      background-color: #FFFFFF;
      overflow-x: hidden;
    }
    .custom-container {
      width: 100%;
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.25rem;
      padding-right: 1.25rem;
    }
    @media (min-width: 640px) {
      .custom-container {
        padding-left: 1.75rem;
        padding-right: 1.75rem;
      }
    }
    @media (min-width: 1024px) {
      .custom-container {
        padding-left: 2rem;
        padding-right: 2rem;
      }
    }
    .glass-nav {
      background-color: rgba(255, 255, 255, 0.94);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(226, 232, 240, 0.8);
    }
    .btn-accent {
      background-color: #F59E0B;
      color: #0F172A;
      font-weight: 600;
      transition: all 0.25s ease-in-out;
    }
    .btn-accent:hover {
      background-color: #D97706;
      transform: translateY(-2px);
      box-shadow: 0 10px 15px -3px rgba(245, 158, 11, 0.3);
    }
    .btn-cyan {
      background-color: #0E7490;
      color: #FFFFFF;
      font-weight: 600;
      transition: all 0.25s ease-in-out;
    }
    .btn-cyan:hover {
      background-color: #155E75;
      transform: translateY(-2px);
      box-shadow: 0 10px 15px -3px rgba(14, 116, 144, 0.3);
    }
    .custom-card {
      background: #FFFFFF;
      border: 1px solid var(--card-border);
      border-radius: var(--card-radius);
      box-shadow: var(--shadow-soft);
      transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.3s ease;
    }
    .custom-card:hover {
      transform: translateY(-4px);
      box-shadow: 0 20px 25px -5px rgba(15, 23, 42, 0.08), 0 8px 10px -6px rgba(15, 23, 42, 0.04);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease-out, padding 0.3s ease;
    }
    .faq-answer.open {
      max-height: 500px;
      padding-top: 1rem;
    }
    .chevron-icon {
      transition: transform 0.3s ease;
    }
    .chevron-icon.rotated {
      transform: rotate(180deg);
    }