/* roulang page: index */
:root {
      --color-primary: #1d4ed8;
      --color-primary-hover: #1e40af;
      --color-accent: #0d9488;
      --color-bg-light: #f8fafc;
      --color-text-main: #0f172a;
      --color-text-muted: #64748b;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      color: var(--color-text-main);
      background-color: #ffffff;
      line-height: 1.6;
    }
    .card-hover {
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .card-hover:hover {
      transform: translateY(-4px);
      box-shadow: 0 12px 24px -10px rgba(15, 23, 42, 0.12);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease-out;
    }
    .faq-answer.open {
      max-height: 300px;
    }
    .rotate-icon {
      transition: transform 0.3s ease;
    }
    .rotate-icon.open {
      transform: rotate(180deg);
    }