@-webkit-keyframes spin {
  0% {
    -webkit-transform: rotate(0deg);
            transform: rotate(0deg);
  }
  100% {
    -webkit-transform: rotate(360deg);
            transform: rotate(360deg);
  }
}

@keyframes spin {
  0% {
    -webkit-transform: rotate(0deg);
            transform: rotate(0deg);
  }
  100% {
    -webkit-transform: rotate(360deg);
            transform: rotate(360deg);
  }
}

.event-thumb__bg:after, .overlay__bg:after, .post-thumbnail:after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-24px, -24px);
  border-radius: 50%;
  width: 24px;
  height: 24px;
  border: 0.25rem solid rgba(0, 0, 0, 0.2);
  border-top-color: black;
  -moz-animation: spin 1s infinite linear;  
  -webkit-animation: spin 1s infinite linear;
          animation: spin 1s infinite linear;
  transition: opacity 0.5s ease;
}

.event-thumb__bg.loaded:after, .overlay__bg.loaded:after, .post-thumbnail.loaded:after {
  opacity: 0;
  animation: none;
}