debugger-app/modules/zoom-sk/zoom-sk.scss

zoom-sk {
  .light-checkerboard  {
    border: solid lightgray 1px;
    background-position: 0px 0px, 10px 10px;
    background-size: 20px 20px;
    background-image: linear-gradient(
      45deg, #eee 25%, transparent 25%, transparent 75%, #eee 75%, #eee 100%),
                      linear-gradient(
      45deg, #eee 25%, white 25%, white 75%, #eee 75%, #eee 100%);
  }

  .dark-checkerboard  {
    border: solid lightgray 1px;
    background-position: 0px 0px, 10px 10px;
    background-size: 20px 20px;
    background-image: linear-gradient(
      45deg, #555 25%, transparent 25%, transparent 75%, #555 75%, #555 100%),
                      linear-gradient(
      45deg, #555 25%, #222 25%, #222 75%, #555 75%, #555 100%);
  }

  .shrink {
    display: inline-block;
    margin-top: 1em;
    margin-bottom: 2em;
    box-shadow: 5px 5px 18px grey;
  }

  .zoom-canvas {
    margin: 0;
    padding: 0;
  }

  .shortcuts {
    margin-left: 1em;
    margin-bottom: 0.5em;
  }

  .shortcuts td {
    padding-left: 0.5em;
  }

  .shortcuts tr {
    padding-bottom: 0.25em;
  }

  .color-preview {
    width: 10px;
    height: 10px;
    margin: 0;
    margin-right: 6px;
    padding: 0;
    display: inline-block;
    border: 1px solid black;
  }
}