/* roulang page: index */
:root {
      --primary: #1e40af;
      --primary-hover: #1d4ed8;
      --accent: #0284c7;
      --surface: #ffffff;
      --surface-sub: #f8fafc;
      --text-main: #0f172a;
      --text-muted: #334155;
      --text-light: #64748b;
      --border-color: #e2e8f0;
      --card-shadow: 0 4px 20px -2px rgba(15, 23, 42, 0.05);
      --hover-shadow: 0 14px 30px -4px rgba(15, 23, 42, 0.12);
    }
    html {
      scroll-behavior: smooth;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif;
    }
    body {
      background-color: var(--surface-sub);
      color: var(--text-main);
      line-height: 1.6;
      overflow-x: hidden;
    }
    .custom-card {
      background: var(--surface);
      border: 1px solid var(--border-color);
      border-radius: 1rem;
      box-shadow: var(--card-shadow);
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .custom-card:hover {
      box-shadow: var(--hover-shadow);
      transform: translateY(-4px);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease-out, opacity 0.3s ease;
      opacity: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 240px;
      opacity: 1;
    }
    .faq-item.active .faq-chevron {
      transform: rotate(180deg);
    }