<!DOCTYPE html>
<title>flexbox | visibility: collapse</title>
<link rel="author" href="http://opera.com" title="Opera Software">
<style>
body {
margin: 0;
}
div {
background: #3366cc;
border: 1px solid black;
}
div::after {
content: "";
clear: both;
display: block;
}
p {
background: #ffcc00;
margin: 2em;
float: left;
}
</style>
<div>
<p>filler</p>
<p>filler</p>
</div>