/* roulang page: index */
:root {
      --bg-main: #0a0d14;
      --bg-surface: #101522;
      --bg-card: #171e2e;
      --color-primary: #00f0ff;
      --color-purple: #7928ca;
      --color-accent: #ff5722;
      --text-white: #ffffff;
      --text-muted: #cbd5e1;
      --text-dim: #64748b;
      --border-light: rgba(255, 255, 255, 0.08);
      --radius-ui: 10px;
    }
    body {
      background-color: var(--bg-main);
      color: var(--text-muted);
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
      line-height: 1.75;
      overflow-x: hidden;
    }
    h1, h2, h3, h4 {
      color: var(--text-white);
      letter-spacing: -0.02em;
    }
    .hero-glow {
      background: radial-gradient(circle at 50% 30%, rgba(0, 240, 255, 0.15) 0%, rgba(121, 40, 202, 0.1) 40%, rgba(10, 13, 20, 0) 70%);
    }
    .card-border {
      border: 1px solid var(--border-light);
      background-color: var(--bg-card);
      transition: all 0.25s ease;
    }
    .card-border:hover {
      border-color: rgba(0, 240, 255, 0.4);
      transform: translateY(-3px);
      box-shadow: 0 10px 25px -5px rgba(0, 240, 255, 0.15);
    }
    .btn-cyber {
      background: linear-gradient(135deg, #00f0ff 0%, #00a8cc 100%);
      color: #050811;
      font-weight: 700;
      transition: all 0.2s ease;
      box-shadow: 0 0 15px rgba(0, 240, 255, 0.25);
    }
    .btn-cyber:hover {
      box-shadow: 0 0 25px rgba(0, 240, 255, 0.5);
      transform: translateY(-2px);
    }
    .btn-outline-cyber {
      border: 1px solid rgba(0, 240, 255, 0.5);
      color: #00f0ff;
      transition: all 0.2s ease;
    }
    .btn-outline-cyber:hover {
      background: rgba(0, 240, 255, 0.1);
      box-shadow: 0 0 20px rgba(0, 240, 255, 0.2);
    }
    details[open] summary svg {
      transform: rotate(180deg);
    }