:root { --bg: #080818; }
  @media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) { --bg: #080818; } }
  :root[data-theme="dark"] { --bg: #080818; }

  html, body {
    height: 100%; overflow: hidden;
    margin: 0; padding: 0;
    background: var(--bg);
    display: flex; align-items: center; justify-content: center;
    touch-action: none; user-select: none; -webkit-user-select: none;
  }

  #gc {
    display: block;
    cursor: pointer;
    border-radius: 14px;
    box-shadow: 0 0 60px rgba(40,80,200,0.22), 0 0 120px rgba(40,80,200,0.09);
  }