How do I display colorized html text in Markdown card?

Does anyone know a WORKING way to colorize a text?

This does not work (as was already said):

type: markdown
title: "Color Test"
content: |
  <span style="color: red;">This is red text.</span>

This does work:

content: |
  <font color=red>This is red text.</font>

but “font” is considered as deprecated; also it does not process CSS color vars properly - see this issue (had to close it since “font” is deprecated):

content: |
  <font color=var(--red-color)>This is red text.</font>

Internet is full of copy/pasted “solutions” which in fact may not work.

P.S. Please do not suggest card-mod.