<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN">
<html lang="en">
<head>
<style>
p:before {
  color: inherit;
  content: 'This text should be green.';
}
</style>
</head>
<body style="color:red">
<p id="foo"></p>
<script>
document.getElementById('foo').style.color='green';
</script>
</body>
</html>