<!DOCTYPE html>
<!--
Any copyright is dedicated to the Public Domain.
http://creativecommons.org/publicdomain/zero/1.0/
-->
<html>
<head>
<title>
CSS Reference
</title>
<style>
.box {
display: flex;
border: 1px solid black;
margin: 5px 20px;
}
.box > * {
border: 1px dotted purple;
}
</style>
</head>
<body>
<div class="box">
<div>1</div>
<div>0</div>
</div>
</body>
</html>