Colored equations? (particularly compiling to HTML)

[Gwern Branwen <gwern-v26ZT+9V8bxeoWH0uzbU5w@public.gmane.org>]

Has anyone found a good way to do annotated colored equations in Pandoc?

A Twitter thread (
https://twitter.com/kwinkunks/status/1232333955501826051 ) of examples
of colored equations like https://row1.ca/pixels-and-their-neighbors
with many implemented in Latex and/or Tikz (
http://www.texample.net/tikz/examples/ ). Rubricated* or colored
equations would be nice to have for Markdown->HTML and other formats.

In an earlier discussion of Pandoc->Docx (
https://groups.google.com/d/msgid/pandoc-discuss/aa5ab201-d3a6-44e2-807d-3f92a97f7a8b%40googlegroups.com
), John says that the texmath package doesn't support the necessary
TeX color library, so you can't simply write out color annotations in
native TeX expressions with $/$$.
People writing Latex->PDF presumably can just use that color library directly.

What other option have people tried?
One could write Latex or anything else and screenshot it as a figure,
but that's not too pleasant or editable.
Could one use the Tikz filter (
https://pandoc.org/lua-filters.html#building-images-with-tikz
https://github.com/jgm/pandocfilters/blob/master/examples/tikz.py
https://github.com/jgm/pandocfilters/blob/master/examples/tikz-sample.md
) or something much like it, to automatically generate a
figure/screenshot? It doesn't yield the same MathML or whatever, and
it might be a little tricky to integrate into Hakyll (unless one
inlined the image as a data-uri? it'd be relatively small).
That might be equivalent to
https://github.com/liamoc/latex-formulae#readme ** which generates
inline PNGs, and https://taeer.bar-yam.me/blog/posts/hakyll-tikz/
which generates inline SVGs.

* https://www.gwern.net/Red
** examples: http://liamoc.net/posts/2017-07-08-abstraction/index.html
http://liamoc.net/posts/2015-11-10-patch-theory/index.html ;
incidentally, he has some very impressive literate Agda code
implementation, examples in
http://liamoc.net/posts/2015-08-23-verified-compiler

-- 
gwern