My list of inbox emails opens on a brilliant white background that hurts my eyes. How to darken it in Windows 10 without changing the background colour of the desktop icons?

Thanks in advance for your help.

Which email service are you referring to? There should be an option in your email settings to change background colour.

I would recommend Proton mail which offers blue, black, and 4 shades of grey under settings.

Many thks for prompt reply, but my problem is the TOO BRIGHT WHITE FIELD AS BACKGROUND TO THE FULL SCREEN when I access the list of incoming emails.
I have no problem with changing the background colour of the desktop itself.

Renewed thanks and best regards.

JOEB.

My reply was referring to the background of the email itself, not the desktop. sleepybear91's reply was also referring to this.