css/css-flexbox/flexbox_generated.html

<!DOCTYPE html>
<title>flexbox | flexcontainer vs generated content</title>
<link rel="author" href="http://opera.com" title="Opera Software">
<link rel="help" href="http://www.w3.org/TR/css-flexbox-1/#flex-containers">
<link rel="match" href="flexbox_generated-ref.html">
<style>
div {
	background: #3366cc;

	display: flex;
}
div::after, p {
	content: "xxx";
	background: yellow;
	margin: 1em;
	width: 200px;
	height: 2em;
}
div::after {
	content: "yyy";
	display: block;
}
</style>

<div>
	<p>FAIL</p>
</div>