body { background-color: #ccc; }

canvas, img {
    image-rendering: optimizeSpeed;
    image-rendering: -moz-crisp-edges;
    image-rendering: -webkit-optimize-contrast;
    image-rendering: optimize-contrast;
    image-rendering: pixelated;
    -ms-interpolation-mode: nearest-neighbor;
}

textarea {
  width: 100%;
}

.canvas-container {
  padding: 0;
  border: 0;
  margin: 0;
  position: relative;
  display: inline-block;
}

.background-preview {
  width: 300px;
  height: 300px;
  display: inline-block;
}