html, body {
  height: 100%;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
}

canvas {
  background: black;
  background-image:url('bg_worm.jpg');
  background-size: contain;
  font-size: 2vw;
  outline: 2px solid #fff;
  outline-offset: -2px;
}