body {
  margin: 0;
  display: block;
  align-content: center;
  background: linear-gradient(black, blue, purple);
}

#mycanvas {
  display: block;
  border: 4px solid rgb(255, 0, 128);
  border-radius: 10px;
  margin: auto;
  background-image: url(images/back2.jpg);
  background-size: 100%;
}

#start {
  display: block;
  margin: auto;
  font-size: medium;
  font-weight: bold;
}
.buttons {
  display: block;
  padding: 10px;
}