Eli Zaretskii <eliz@gnu.org> writes:

> We can (and did) tweak the various constants involved in this, more
> than once.  The lesson I took from that is that we could never produce
> something that will fit all the needs, let alone satisfy all the
> users.  There are two main factors here on which we have no control:
> the subjective differences between color perception by different
> people, and variations in how different terminals and displays show
> the same colors.
>
> That is why I object to making changes in this low-level functionality
> with the motivation of "fixing them all": I think it's simply
> impossible.  We will make it slightly better in some situations and
> slightly worse in others.  There's no net win here.

Maybe the ultimate fix in CSS mode's case could be to display the color
separate from the text. Firefox, for instance, displays the color in a
little circle next to the color code (screenshot attached). I'm not sure
how to implement it in Emacs, though.

-- Simen