Here's my first-para style:
p.first {
margin-top:0.5em;
margin-bottom: 0.0em;
text-indent:0.0em;
text-align:justify;
}
You can copy my entire style sheet from
http://notjohnkdp.blogspot.com/
Note that you call that style by beginning the para <p class="first">
My invariable resource is Google. I'll bet if you Google "CSS for first paragraph," you'll get heaps of information.