#designer-root {
  margin: 20px auto;
  max-width: 520px;
}
#designer-canvas {
  background-image: linear-gradient(45deg, #ccc 25%, transparent 25%),
                    linear-gradient(-45deg, #ccc 25%, transparent 25%),
                    linear-gradient(45deg, transparent 75%, #ccc 75%),
                    linear-gradient(-45deg, transparent 75%, #ccc 75%);
  background-size: 20px 20px;
  background-position: 0 0, 0 10px, 10px -10px, -10px 0px;
}