.instructions {
  text-align: center;
}

canvas {
  background-image: url("http://www.gunnars.com/wp-content/uploads/2014/08/Space.jpg");
  background-size: cover;
  padding-left: 0;
  padding-right: 0;
  margin-left: auto;
  margin-right: auto;
  display: block;
  box-shadow: 1px 1px 50px white;
  border-radius: 10px;
}