An ebook that doesn’t have structure is broken and unacceptable. […] The more I discover about existing publisher ebook production processes, the more I talk to people ‘on the inside’, the clearer it becomes that a substantial portion of existing ebook inventory is quite simply rubbish. No structure. Crap stylesheet. Broken markup. So I propose that ereader vendors simply turn all publisher styles off and never even consider enabling javascript. […] In exchange, what we need you to do is to improve your built-in stylesheets. We need you to support common markup practices like figures and captions, headings and subheadings, horizontal rules that don’t look like a 90s flashback and so on. Best if you support them both in markup patterns and as class-based microformats.

“Just say no to ebook CSS and JS”, Baldur Bjarnason, 2 October 2013