(re-post cause everyone interested seems to have left those treads)
This is what you want, black bkgd and buttons...
All you need to do is theme windows... download this one, it will theme Tixati as well...
Unzip, copy all the win theme stuff folder to ---C:\Windows\Resources\Themes
you're gonna want 1 of the 4 "night" ones, the dark ones dont affect Tixati, and the only difference between the 4 is the style of the min-max-close on windows upper-right corners.
Then you need a theme patcher that will allow these themes to be use by windows or something like that.
there's that https://uxthemepatcher.com/
which works well, but there's also 3-4 others, ultraUXpatcher, SecureUxTheme, etc...
they'll then be in the windows settings > personalization > theme > just click on it... I have it on Win11, but it should work on Win10 as well, just didnt test it.
There's also Arctica, Catppuccin, PA_Lovelace, Lovelace, Tokyo Night, Everforest and Everblush from Niivu which will darken Tixati in a slightly better way i believe but they'll also make all your context menu with a white background which i find annoying... it's a trade-off i guess, try them.
May the DarkSide be with you.. Always! ;-)