I don't want true colours. I want what I already have, 16-255, to stay reliable in the future.
XKCD 1172? https://xkcd.com/1172/
What would be optimal is semantic _styles_ (not colors):
- The developer marks the string "XXX" as an error message without even trying to style it.
- The platform/user agent/terminal/whatever displays the string in the default style for "error".
- The user can adjust the theme of their platform/user agent/terminal/whatever to fit their needs/wants.