css/css-flexbox/abspos/position-absolute-containing-block-002.html

<!doctype html>
<title>CSS Test: Absolutely positioned children of flex container with CSS align</title>
<meta charset="utf-8">
<link rel="help" href="https://drafts.csswg.org/css-flexbox/#abspos-items">
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1386654">
<link rel="match" href="position-absolute-containing-block-002-ref.html">
<link rel="author" title="Emilio Cobos Álvarez" href="mailto:emilio@crisal.io">
<style>
.parent {
  position: fixed;
  top: 0;
  left: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 180px;
  height: 180px;

  /* Expand the background area to 200px, without touching the content-box,
     which is what flex absolute children should be aligned relative to. */
  border-top: 5px solid yellow;
  padding-top: 15px;
  border-left: 5px solid yellow;
  padding-left: 15px;

  background: yellow;
}

.child {
  position: absolute;
  width: 100px;
  height: 100px;
  background: green;
}
</style>
<div class="parent"><div class="child"></div></div>