<p> is your basic paragraph style. Mine is this:
p {
margin-top:0.0em;
margin-bottom:0.0em;
text-indent:1.5em;
text-align:justify;
}
You don't need to add a "class" unless you're doing something different, as in <p class="first"> which for me is this:
p.first {
margin-top:0.5em;
margin-bottom: 0.0em;
text-indent:0.0em;
text-align:justify;
}
My entire style sheet is at
https://notjohnkdp.blogspot.com/ which you are welcome to borrow or adapt.