.lens {
  border: 2px solid #fff;
  background: rgba(255,255,255,0.5);
}

.preloader {
  height: 50px;
  width: 50px;
  border: 1px solid #000;
  background: url('https://www.prosveta.fr/resources/sites/3/js/images/preloader.gif') no-repeat center center #fff;
  margin-left: -25px; /* Must be 50% of width */
  margin-top: -25px; /* Must be 50% of height */
  border-radius: 5px;
}

.popover {
  background: #fff;
  border-radius: 5px;
  /*border: 1px solid #888;*/
}

.popover_sandbox img, .popover img {
  max-width: none;
}