<!DOCTYPE html>
<!-- There should no text in black color. -->
<html>
<body>
<style>
rt:before 
{
   content: "BEFORE";
}
rt:after
{
   content: "AFTER";
}
</style>
<ruby>
A<rt>CONTENT</rt>B
</ruby>
<script>
    document.body.offsetTop;
    document.body.style.color = 'blue';
	document.body.style.zoom = '200%';
</script>
</body>
</html>