OK, now I am completely flummoxed. I can't find any difference between the code in the sample you sent and my own document. When I open the sample in Sigil, I don't get the spaces, but on my own document I do.
Did you alter the document in any way?? What's happening (aaaarrrggghhh!!!)
UPDATE: Never mind, the p {margin: 0; } did the trick. Whoohoo!
NOW ... is there an easy way to get the first line of each paragraph to indent, but not the first line of each chapter? - Or, if it's too much fuss to leave out the first line, I can do that manually.
Thanks so much!