<html><head>
<title>Syntax and parsing of unknown pseudo-classes</title>
<style type="text/css">
p { background: lime; }
p:subject { background: red; } /* this is not valid CSS, and if UAs
implemented the experimental :subject pseudo-class they should have
used the :-vnd-ident syntax. */
</style>
<link rel="author" title="Ian Hickson" href="mailto:ian@hixie.ch">
<link rel="help" href="https://www.w3.org/TR/css3-selectors/#selectors"> <!-- bogus link to make sure it gets found -->
<link rel="match" href="reference/this-line-lime-background.xht">
<meta name="flags" content="">
</head>
<body>
<!--[ELEMENT('p')]--><p><!--[TEXT('p')]-->This line should have a green background.<!--[/TEXT('p')]--></p><!--[/ELEMENT('p')]-->
</body></html>