[tde-users] how to force TDE colors in non-TDE apps?

I did try to accomplish this by going through the Trinity Control Center / Appearance / Colors, but nothing happens to my non-TDE apps, so far as I can tell. (Actually, I am only guessing, from what I remember; my TCC screen has been frozen now for a couple hours. See attachment.) Some of my apps refuse to change colors, even though they used to behave like I want (in Jessie, that is, before I upgraded to Devuan Beowulf). I seem to recall that E.Liddell, or maybe Nik, offered some css tricks to do something like this? The main thing is that I don't want to look at a white screen, but I prefer to keep my own color scheme, not to use one of those ready-made themes. Right now it is psi-plus that won't accept the color scheme that I used before the upgrade; it accepts some of the definitions, but will not change background colors. By the way, if I could get kopete to work again, that would be fine, too, but kopete-trinity lags behind other chat applications. Pidgin is okay, and I have others that I am trying out, but at present psi-plus works best for me ... except for the white background, which tends to be hard on my old eyes and gives me a headache. Any suggestions on how to fix the problem or for a workaround? Thanks for any help! Bill