<!DOCTYPE html>
<!-- Any copyright is dedicated to the Public Domain.
- http://creativecommons.org/publicdomain/zero/1.0/ -->
<html>
<style>
div#details {
display: inline-block;
}
</style>
<body>
Details element:
<div id="details">
<div>Summary</div>
<p>This is the details.</p>
</div>
</body>
</html>