[Evolution] More dark theme issues

[aguador <waterbearer54 gmx com>]

I have Evo 3.32.x running in Mageia 7, Enlightenment 0.22.4, and 3.36.0
in Mageia Cauldron with Enlightnemtn 0.23.1 -- with Webkit2gtk 2.28.0
in both. Let me deal with Cauldron (3.36.0) which is my main system.

The handling of HTML is, well, uneven with dark themes -- and I get a
lot of HTML mail involving newsletters, some translation work offers,
and messages from friends and colleagues. Between yesterday and today I
have seen three variations:

 * Yesterday, the offer of a translation job was a barely legible
   light-grey on white (illegible in bright lighting) [the client uses
   https://www.gespoint.com/ to generate the messages/offers which link
   to the web to accept, reject, and add notes]
 * Today an e-mail message had a combination of invisible and visible
   text (specifically from here:https://www.wordsmith.org/awad/)
 * Also today something I have seen on other days: black letters on a
   dark-grey to black background. These are legible in the dark grey
   "shades of gray" themes, not really so with Adwaita dark. (A good
   example is the newsletter from https://theconversation.com/us.)

Questions:

 * Are others seeing this?
 * Do we know what is going on/how to fix it?
 * What information can I provide to help?

Best,
Roy