chromium/third_party/blink/web_tests/fast/media/mq-relative-constraints-07.html

<html>
<head>
<title>CSS3 media query test: media query testing constraints with relative values evaluating false (screen and (max-width: 30em)). Using style element, @media css rule.</title>
<link rel="help" href="http://www.w3.org/TR/css3-mediaqueries/#width" />
<style type="text/css">
p { color: green }
@media screen and (max-width: 30em) {
p { color: red }
}
</style>
</head>
<body>

<p> This text should be green if viewport is wider than 30em. This tests that (max-width: 30em) can evaluate to false. </p>

<div style="width: 30em; background-color: lightblue;"> div of length 30 em </div>
<div style="width: 800px; background-color: lightblue;"> div of length 800px </div>
</body>
</html>