It depends on which is effecting the paragraph.
If you look in your text (in code view of course), you are looking for something like:
Code:
<p class="calibre2">
I just chose one of the ones in your CSS at random, but it could be any of the others (I suspect it will be calibre2 from what I can remember from my conversions using Calibre). Once you find it, you will know which one to alter.