Resolved Gmail Background Changed to Black

A friend's Gmail background recently changed to black. He upgraded to W11 a week or so ago but he can't recall whether the black background change happened before or after. The Compose screen is also black. He is able to use his Gmail but the tools are very difficult to see.
I have tried to change to the GMail default Theme using Settings but nothing happens when I select it. I feel like there is some task or procedure I am missing but can't seem to make it work. Any suggestions?

 

Steve,
The link you gave me is what I have tried. In the "Themes", I am unable to select any theme - the screen stays black on Gmail no matter what I do. The theme we want is the Gmail default and nothing happens when we select it. On my computer, I can change to any of the themes shown with no issue. And my Compose screen opens in default mode but the problem computer has a black Compose screen Any other thoughts?

 

A reboot didn't do anything?

 

Mr. Bill and Steve - Thanks. We got the problem resolved. As I was checking the Update Settings on his W11 machine, he noticed the Accessibility feature and asked what it was. I selected it and we saw an option for Contrast Theme. A sub option was "Desert". When we selected it, the black screen went away. So he is happy.
Don't know if the initial change to the black screen was due to W11 update or not but I did notice that getting to the "Contrast Theme" option is significantly different on my Windows 10 machine.

 

Hi Robert, I often wonder whether WU does cause an error to occur now and again.
My HP laptop frequently went to FULL volume on speakers after updates.
In WU > Advanced Options > Delivery Optimizations, where does it allow updates from?

 

Did you click the Gear near the top and go to Themes and try to change it there?

 

RL, I have always turned Delivery Optimization off as I understood that when it is on, your computer becomes part of a ?neighborhood or world wide internet connection that let's everyone share - good stuff as well as bad stuff. Technology socialism?
Bill, we were never able to do anything from the Settings - it was as though it were frozen.