ok, and I'm not terribly bright today. I found how to quality check only a selected book. I've got the book only in epub, and checked the epub styles, and it apparently came out clean.
I went in to the html files themselves looking for problems - it turns out every paragraph is in blockquote tags.
It's too much work to go into every single html file and delete the blockquote tags by hand - I guess I'll just have to put up with a wide left margin as I read.
thanks for all the help and suggestions!