I'm using Chrome. Tried Edge and my phone browser and still the same problem. Cleared cookies, logged out, Ctrl F5 etc. It seems that I'm stuck in mobile mode. I dont have the option to change theme at the bottom of the index page nor the option to change the theme in user CP. I cant post an image of the problem as you cant attach files in mobile mode.
Just the fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus, they laughed at Fulton, they laughed at the Wright brothers. But they also laughed at Bozo the Clown.