Originally Posted by jackie_w
If it's too difficult (or contentious) put the idea aside for now. It's something I, personally, would use for some epubs because I don't like zero margins. However, I'm perfectly capable of hand-editing either the xpgt or css, or of doing the epub-epub conversion to fix the problem.
If you do an ePub > ePub conversion of say a publisher created ePub, you definitely can make it a bit of a mess. Calibre does a poor job sometimes going ePub > ePub. For example, if you have embedded fonts, Calibre takes the code out of the CSS and puts the @font code into every XML file. IT can also change the directory structure. So really, once the ePub is made, don't use Calibre to convert it. It's not pretty.