html, body {
  margin: 0;
  height: 100%;
  overflow: hidden;
  background: #05060a;
  touch-action: manipulation;
}

#c {
  display: block;
  width: 100vw;
  height: 100vh;
}

.hint {
  position: fixed;
  left: 12px;
  bottom: 12px;
  font: 12px/1.3 system-ui, -apple-system, Segoe UI, Roboto, sans-serif;
  color: rgba(255,255,255,0.55);
  user-select: none;
  pointer-events: none;
  text-shadow: 0 1px 10px rgba(0,0,0,0.6);
}