Well I would use
font-size : 2em;
for instance. What are your issues?
Modified with example:
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<style type="text/css">
div#myText {
font-size: 1.5em;
width : 200px;
height : 50px;
border: solid 5px green;
}
</style>
</head>
<body>
<div id="myText" style="width:1000px; height:400px; border: solid 5px green">
This is some text in a div tag
</div>
</body>
</html>
Look for font-size inside the style tag in the head section of the html.
End modification. Observe how the link from CSS to the div is made by the CSS selector
div#myTxt
.
Regards,
Manfred