Well, progress on integrating MathML in just about anything sounds pretty depressing these days, with support for it removed from Chrome...
My biggest fear is that it'll prove too difficult to get consistent placement of stuff like indexes with HTML/CSS, even if I use tailor-made classes rather than <sup>/<sub>. Oh well, I suppose I'll have to resort to tables ... that'll make for nice, readable code

Anyway, at this stage I am hedging my bets and coding all the maths as LaTex, and then I'll convert it to the most suitable format at the end.
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There are 3 kinds of people: Those who can count, and those who cannot.