WXXR/miniprogram/pages/physics/scene-physics-throw/index.wxss

.overlay {
  display: block;
  position: absolute;
  z-index: 10;
}

.button {
  width: 50px;
  height: 50px;
  background-color: rgba(0, 140, 255, 0.5);
  text-align: center;
}