[enuddleyarbl]

The odd thing is that I've never seen anything in those page_styles.css files except an @page with all margins 0. Lately, I've been working on reformatting my copies of Rex Stout's "Nero Wolfe" series. Those books contained 2-3 page_styles[n].css files that were always the same (I assume I must have done multiple conversions on them over the years to cause that). Since each file also contained stylesheet.css with all the actual formatting, I just removed the links to the page_styles versions and deleted those files.

EDIT: I think I've figured out what's happened with these. One of the first things I do is use Modify ePub on my books and remove all embedded fonts. I'll bet those fonts were referenced in the page_styles.css file. Once the fonts were gone, the page_styles.css files were left with nothing but the zero-margin @page.