[markdown] How to apply color in Markdown?

I like the idea of redefining existing tags if they're unused due to the fact that the text is cleaner, at the expense of existing tags. The inline styling works but creates a lot of noise when reading the raw text.

Using VSCode I've found that custom single-letter tags, supported by a small <style> section at the top, works well with a minimum of noise, especially for spot colour, e.g.

<style>
r { color: Red }
o { color: Orange }
g { color: Green }
</style>

# TODOs:

- <r>TODO:</r> Important thing to do
- <o>TODO:</o> Less important thing to do
- <g>DONE:</g> Breath deeply and improve karma

My use-case is orgmode-ish in-app note taking during development but I guess it might work elsewhere?