body, html {
  margin: 0;
  padding: 0;
  overflow: hidden;
  height: 100%;
  background: url('muro-de-hormigon-pintado-solido-con-textura-de-fondo.jpg') no-repeat center center;
  background-size: cover;
}

canvas {
  position: absolute;
  top: 0;
  left: 0;
  touch-action: none;
}

.controls {
  position: fixed;
  top: 10px;
  left: 10px;
  background: rgba(255,255,255,0.2);
  padding: 10px;
  border-radius: 10px;
  color: white;
  font-size: 18px;
}