html,
body {
  margin: 0;
  padding: 0;
  overflow: hidden;
  background-color: #000;
}
canvas {
  display: block;
}
#overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: rgba(0, 0, 0, 0.7);
  color: white;
  font-family: Arial, sans-serif;
  font-size: 24px;
  cursor: pointer;
  text-align: center;
  z-index: 10;
}