/* roulang page: index */
:root {
      --primary-black: #0F141C;
      --deep-black: #0B0F17;
      --accent-cyan: #0EA5E9;
      --accent-green: #10B981;
      --text-main: #0F172A;
      --text-muted: #475569;
      --border-soft: rgba(226, 232, 240, 0.9);
      --bg-base: #F8FAFC;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      color: var(--text-main);
      background-color: var(--bg-base);
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      text-rendering: optimizeLegibility;
      -webkit-font-smoothing: antialiased;
    }
    .hero-glow {
      background: radial-gradient(circle at 50% 20%, rgba(14, 165, 233, 0.12) 0%, rgba(15, 20, 28, 0) 70%);
    }
    .card-hover-effect {
      transition: transform 0.25s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.25s cubic-bezier(0.16, 1, 0.3, 1), border-color 0.25s ease;
    }
    .card-hover-effect:hover {
      transform: translateY(-3px);
      box-shadow: 0 16px 32px -8px rgba(15, 23, 42, 0.08);
      border-color: rgba(14, 165, 233, 0.4);
    }
    .section-dark-grid {
      background-image: linear-gradient(to right, rgba(255, 255, 255, 0.03) 1px, transparent 1px),
                        linear-gradient(to bottom, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
      background-size: 40px 40px;
    }
    .faq-answer {
      transition: max-height 0.3s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.3s ease;
    }