sousa-gecko/testing/web-platform/tests/css/css-view-transitions/outer-padding-inner-background-ref.html

<!DOCTYPE html>
<html>
<link rel="help" href="https://drafts.csswg.org/css-view-transitions-1/">
<style>
:root  { background: rebeccapurple; }
.target {
  width: 200px;
  height: 200px;
  contain: paint;
  view-transition-name: target;
  padding: 20px;
}

.child {
  width: 100px;
  height: 200px;
  position: relative;
  background: green;
}
</style>

<div class=target>
  <div class=child>
  </div>
</div>