If you take a look at my palette you will see that my background has a peachy color as well as an image in the other background.
The peach color can be changed in the area of code titled Set Page Background Color.
The section where I changed the image is titled Set Website Background and it is the second to last section of coding. You can insert your own image, or keep it just a solid color!
The part where it says Featured Horse, etc. is still a mystery to me. I believe only one person has succeeded in changing that and I don’t think the trick has been made known to very many people so far. XD
I hope this helps, PM me if more clarification is needed!