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                <div class="callout">
  <h2>Hey, you there!</h2>
  <p>This is important information, so I'd like to draw your eye to it. I'm going to put a little shine on this box, but I won't make it repeat forever because that may cause accessibility issues.</p>
  <p>Make sure to do the thing with the stuff!</p>


                /* Put a shiny effect on the callout */
.callout {
  background-image: linear-gradient(135deg, #9bf0e9 0%, #fff 37.5%, #9bf0e9 75%, #9bf0e9 100%);
  background-size: 400%;
  animation-name: shiny;
  animation-duration: 2s;
  animation-delay: 2s;
  animation-fill-mode: forwards;

@keyframes shiny {
  0 {
    background-position: 0 0;
  100% {
    background-position: 100% 100%;

/* Set-up styling (not key to the approach illustrated here) */
.callout {
  margin: 1.5em;
  padding: 1.5em;
  width: 30em;
  font: 1.125em/1.4 "Segoe UI", -apple-system, BlinkMacSystemFont, Roboto, Oxygen-Sans, Ubuntu, Cantarell, "Helvetica Neue", sans-serif;

h2 {
  margin-top: 0;