script>

<style>
#container {
  width: 150px;
  height: 150px;
  background: lightblue;
  will-change: transform;
}
.hidden {
  content-visibility: hidden;
}
#child {
  width: 50px;
  height: 50px;
  background: red;
  will-change: transform;
}
</style>

<div id=container>
  Test fails if you can see this text or a red box.
  <div id=child></div>
</div>

<script>
function runTest() {
  const container = document.getElementById("container");
  container.classList.add("hidden");
  requestAnimationFrame(takeSc