Hey, Tex, pardon this brief reply -- I'm having some health issues at the moment, plus my keyboard is totally acting up on me and screwing up text I'm trying to type.
You make some very good points -- in particular about cleaning up all that redundancy in my CSS. And re #1, I meant in Sigil and ADE (and I
presumed in iBooks).
VERY interesting about that zero-width joiner, too!
Oh, dammit! I can't type on this stupid keyboard!!!

Let me get back to you, once I have a new keyboard, hopefully feel better, and I'll see if I can improve my CSS/HTML (and also my fonts need some fix-ups, too).
Might take me a couple/few days -- sorry, this keyboard issue is driving me crazy!