Originally Posted by dauwhe
ePub fully supports CSS 2.1 and I think almost all of XHTML. Mobi/AZW's CSS support is, what's the polite word, terrible. No support for float, almost all the box model fails, etc.
i'm no expert, but from reading the OPS standard, it seems epub supports only CSS 2.0, not full 2.1. from the standard:
This specification defines a style language based on CSS 2. (Note that the CSS 2.1 specification is currently still at "Working Draft" status.)
furthermore, to quote the standard "...not all CSS 2 properties are included." there's a required subset of CSS properties that must be supported by epub reading systems.
I'm reading this at http://www.idpf.org/2007/ops/OPS_2.0...l#Section1.3.5
extending that thought... why is creating an epub reading system so difficult? epub files are basically just simple webpages of text. any reader just has to use a copy of webkit or gecko or some other open-source renderer to make an epub reading system that supports far more advanced things than are required by the epub specs. reading systems may perhaps simply need to add a few "hacks" to create reader-specific thing, perhaps something related to pagination or whatnot.