Currently, the indicator color for which email is open is insanely bright and takes away the focus from the actual email to the color of the indicator. In fact, the color is so bright that I'm having problems concentrating on the email and instead am constantly moving my eyes towards this indicator. This is true for all themes.

Compare this to other clients like gmail or outlook which have way more subtle highlighting on the current email.

Heres a drive link to 2 images of the mail client, where one is the current "snow" theme, and in the other I have edited the css indicator color to be the way more subtle #efe9ff.
https://drive.proton.me/urls/308RAJ72CM#N5AYEO03JEst

This may sound minor or picky, but is something actively stressing my eyes, and potentially these of other users.

(Maybe the "New Message" button could also be slightly lighter but thats less important and probably more controversial)