[Evolution] Change color of unread email

[Prometheus <pr0m gmx com>]

Is there a preferably easy way to change the color of unread e-mails? I
am using Adwaita Dark and when a new mail arrives it's background is
the same as the other e-mail.

I've searched over the internet and found only some solutions with
changing css files but all had many problems as some "old solutions"
stopped working while others pointed to files that I couldn't find in
the folders they pointed.

My Evolution version is : 3.22.4

and I am on Debian Strech / Gnome 3.22.2

Thanks:)