/* roulang page: index */
:root {
      --bg-dark: #0B1120;
      --bg-surface: #0F172A;
      --card-bg: rgba(30, 41, 59, 0.65);
      --cyan-bright: #06B6D4;
      --blue-accent: #3B82F6;
      --text-main: #F8FAFC;
      --text-muted: #94A3B8;
      --border-light: rgba(255, 255, 255, 0.08);
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
      -webkit-font-smoothing: antialiased;
    }
    body {
      background-color: var(--bg-dark);
      color: var(--text-main);
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      line-height: 1.7;
      overflow-x: hidden;
    }
    .glass-card {
      background: var(--card-bg);
      backdrop-filter: blur(14px);
      -webkit-backdrop-filter: blur(14px);
      border: 1px solid var(--border-light);
      box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.35);
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .glass-card:hover {
      border-color: rgba(6, 182, 212, 0.4);
      transform: translateY(-3px);
      box-shadow: 0 12px 36px 0 rgba(6, 182, 212, 0.15);
    }
    .glow-btn {
      background: linear-gradient(135deg, #06B6D4 0%, #3B82F6 100%);
      box-shadow: 0 0 20px rgba(6, 182, 212, 0.45);
      transition: all 0.25s ease;
    }
    .glow-btn:hover {
      box-shadow: 0 0 28px rgba(6, 182, 212, 0.65);
      filter: brightness(1.08);
      transform: translateY(-2px);
    }
    .ghost-btn {
      background: rgba(15, 23, 42, 0.7);
      border: 1px solid rgba(255, 255, 255, 0.15);
      backdrop-filter: blur(8px);
      transition: all 0.25s ease;
    }
    .ghost-btn:hover {
      border-color: var(--cyan-bright);
      color: #38BDF8;
      background: rgba(30, 41, 59, 0.8);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease-out, padding 0.35s ease;
    }
    .faq-item.active .faq-answer {
      max-height: 220px;
      padding-top: 0.75rem;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    .section-spacing {
      padding-top: 5rem;
      padding-bottom: 5rem;
    }
    @media (max-width: 768px) {
      .section-spacing {
        padding-top: 3.5rem;
        padding-bottom: 3.5rem;
      }
    }