* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

html, body {
  padding: 5px;
  height: 100%;
  width: 100%;
  background: black;
}

canvas{
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}