/* CANVAS */
canvas {
  width: 100%;
  border: 1px solid #000000;
  margin: auto;
}
#cnv {
  text-align: center;
  border: 1px solid firebrick;
  padding: 1em;
}

@media screen and (orientation: landscape) {
  #cnv canvas {
    width: 50%;
  }
}