With the following styles applied:

<style type="text/css">
h1 { font: bold 18pt/24pt Verdana, Arial, sans-serif ; color: #990000 }
h2 { font: bold 15pt/18pt Verdana, Arial, sans-serif ; color: #009900 }
h3 { font: bold italic 15pt/18pt Verdana, Arial, sans-serif ; color: #009900 ; text-indent: 1em }
h4 { font: bold 12pt/18pt Verdana, Arial, sans-serif ; color: #000099 }
h5 { font: bold italic 12pt/18pt Verdana, Arial, sans-serif ; color: #000099 ; text-indent: 1em }
h6 { font: bold 12pt/16pt Georgia, Times, "Times New Roman", serif ; color: #000000 ; text-indent: 1em }
</style>

Heading 1

Heading 2

Heading 3

Heading 4

Heading 5

Heading 6

<h1>Heading 1</h1>
<h2>Heading 2</h2>
<h3>Heading 3</h3>
<h4>Heading 4</h4>
<h5>Heading 5</h5>
<h6>Heading 6</h6>

»