/* roulang page: index */
:root {
      --color-dark: #0B0F17;
      --color-cyan: #0EA5E9;
      --color-blue: #2563EB;
      --color-light: #F8FAFC;
      --color-text: #1E293B;
      --color-muted: #64748B;
      --border-fine: rgba(226, 232, 240, 0.8);
    }
    html {
      scroll-behavior: smooth;
      overflow-x: hidden;
    }
    body {
      color: var(--color-text);
      background-color: #ffffff;
      font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
      overflow-x: hidden;
      margin: 0;
      padding: 0;
    }
    .tech-grid-bg {
      background-size: 36px 36px;
      background-image: 
        linear-gradient(to right, rgba(14, 165, 233, 0.04) 1px, transparent 1px),
        linear-gradient(to bottom, rgba(14, 165, 233, 0.04) 1px, transparent 1px);
    }
    .tech-grid-dark {
      background-size: 40px 40px;
      background-image: 
        linear-gradient(to right, rgba(14, 165, 233, 0.08) 1px, transparent 1px),
        linear-gradient(to bottom, rgba(14, 165, 233, 0.08) 1px, transparent 1px);
    }
    .card-hover-fx {
      transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    }
    .card-hover-fx:hover {
      transform: translateY(-4px);
      box-shadow: 0 16px 32px -8px rgba(15, 23, 42, 0.08);
      border-color: rgba(14, 165, 233, 0.4);
    }
    .hero-h1 {
      font-size: clamp(2.25rem, 4.2vw, 3.75rem);
      line-height: 1.15;
      letter-spacing: -0.02em;
    }
    .crosshair-corner {
      position: relative;
    }
    .crosshair-corner::before,
    .crosshair-corner::after {
      content: '';
      position: absolute;
      width: 8px;
      height: 8px;
      border-color: var(--color-cyan);
      pointer-events: none;
    }
    .crosshair-corner::before {
      top: -1px;
      left: -1px;
      border-top: 2px solid var(--color-cyan);
      border-left: 2px solid var(--color-cyan);
    }
    .crosshair-corner::after {
      bottom: -1px;
      right: -1px;
      border-bottom: 2px solid var(--color-cyan);
      border-right: 2px solid var(--color-cyan);
    }
    .tab-active {
      background-color: #0EA5E9;
      color: #ffffff;
      border-color: #0EA5E9;
    }
    .faq-panel {
      transition: max-height 0.3s ease-out, opacity 0.25s ease-out;
    }