message: Add black background for caption
diff: }
  .controls-caption {
  - opacity: 0.5;
  + opacity: 0.7;
  top: 0;
  position: absolute;
  height: initial;
  width: 75%;
  padding: 5px 13px;
  font-size: 1.5rem;
  + background-color: rgba(0,0,0,0.2);
  + border-radius: 5px !important;
  }
  .controls-zoom {
  