Thank you for your work. I really like pEp.
But for eye comfort please add a nightmode/darkmode to the Android version (I'm using the F-Droid version) of your program.
It's very hard for me to read emails at evening or night with your Android application because it hurts my eyes and irritates the human cirdian rhythm (sleep wake rhythm) because the bright white light that comes from the standard day theme of your application activates to much of the eye receptors for daytime.
I'm sure a lot of other folks will also be thankful for a nightmode too.