How to Set Calibre E-Book Viewer to Dark Mode?

[JusGellin]

I tried to do this by making a file called :
/etc/profile.d/calbre_darkmode

Then in the file added:
export CALIBRE_USE_DARK_PALETTE=1

But nothing happens.
How can I do this?

Thanks

[JusGellin]

When I search for the environmental variable:
printenv | grep CAL
it shows it is there:
CALIBRE_USE_DARK_PALETTE=1

Why isn't it going to the dark mode especially in the e-reader like I want?
How can I troubleshoot this?

[mikewalsh]

@JusGellin :-

Some apps simply WILL not run in "dark mode", even if any config stuff pertaining to it is correctly set-up. Me, I prefer everything dark, so I just set a dark theme globally.

I found a beautiful dark theme called "SlicknesS-Black" from gnomelook.org a couple of years ago. Unfortunately, it won't work with the newest Puppies/Dogs/whatever, because it's a GTK-2.0 theme.......and Woof-CE is now set-up to build Puppies with GTK-3.0 ONLY. (Summat to do with 'maintaining widget compatibility with new software', apparently...)

(*shrug....*)

Mike.