bullseye: GNOME, Thunderbird, font styles?

[Kristian Rink]

Folks;

unsure whether this belongs here (apologies if not): Using Thunderbird 
78 and GNOME on Debian bullseye, I wonder whether there is any way to 
make Thunderbird comply with the font (size, style) settings of the rest 
of the desktop? Spent a fair amount of time trying to tweak this, but 
results are pretty mediocre. :(

Thanks in advance for any hints.

Kristian