"Supporting all the features required" and being able to rely on them on most platforms and in most readers are a very different thing. HTML and CSS theoretica

"Supporting all the features required" and being able to rely on them on most platforms and in most readers are a very different thing. HTML and CSS theoretically have these properties, but if you asked someone in the publishing industry to layout a book with them they would either quit on the spot or hate you until their dying breath. That or they're a masochist and want to see if they could actually do it because it is theoretically possible.