As a simple example, suppose that you wanted to make all of the text inside <H3> tags blue. To do this, you could include stylesheet information in the document header like this:
<HTML>
<HEAD>
<TITLE>A Brief Introduction to Style Sheets</TITLE>
<STYLE type="text/css">
H3 {color:blue}
</STYLE>
</HEAD>
Now, let's take a look at the resulting Hn elements:
Well, how about that--it seems to work.I'm an H1 element
I'm an H2 element
I'm an H3 element
I'm an H4 element
I'm an H5 element
I'm an H6 element