Evolution system fonts size?

Does anybody know how to change sytem fonts in flatpak Evolution email client 3.44.2 ?
(e.g. menu font +email folders sidebar font)
From non -techy Stephen, “PC diy fiddler”

Project information: system fonts size?

Name: Evolution
Upstream has been contacted:

Yay! I’ve found/worked out the fix:

Set 2x flatpak environment variables for flatpak evolution:
e.g. using flatpak flatseal app

(Or for other flatpak and set values to whatever you want, e.g. 1.2 to make even bigger, but I’m not sure yet (from playing with diff values) how they interact.)

(The www source I found suggested 1 variable =0.5 and other =1.5 but I can’t recall which way around.).