html,
body {
  margin: 0;
}

.canvas {
  width: 100%;
  height: 100vh;
}
#blocker {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
}
iframe {
  transform-style: preserve-3d;
  backface-visibility: hidden;
  pointer-events: auto;
}
#switch {
  position: absolute;
  bottom: 20px;
  left: 20px;
  z-index: 10;
  padding: 10px 20px;
  background-color: #007bff;
  color: white;
  border: none;
  border-radius: 5px;
  cursor: pointer;
}