<!DOCTYPE html>
<html class="reftest-wait">
<title>CSS Positioned Layout Module Test: 'overlay' rendering on top after transition finished</title>
<link rel="help" href="https://drafts.csswg.org/css-position-4/#overlay">
<link rel="help" href="https://html.spec.whatwg.org/multipage/popover.html">
<link rel="match" href="green-ref.html">
<script src="/common/reftest-wait.js"></script>
<style>
  #transition-in, #red {
    /* Force display:block both popover open or closed to not rely on
       @starting-style or display transitions. */
    display: block;
    border: none;
    width: 100vw;
    height: 100vh;
  }
  #red {
    position: fixed;
    background-color: red;
  }
  #transition-in {
    transition: overlay 0.1s step-end;
    background-color: green;
  }
</style>
<div id="transition-in" popover></div>
<div id="red"></div>
<script>
  let transition_in = document.querySelector("#transition-in");
  transition_in.addEventListener("transitionend", () => takeScreenshot());
  // Force style update to have before-change style for overlay transition.
  transition_in.offsetTop;
  transition_in.showPopover();
  if (getComputedStyle(transition_in).overlay != "none") {
    // Transition didn't start, force a fail condition.
    transition_in.style.backgroundColor = "pink";
    takeScreenshot();
  }
</script>
