Background Image

Hi,
I am using the below CSS to have a background image on my home page. I am using the full width option so was advise to use this code. However, what is the way to have an image on a different page.

.home #main-content {background-color: #FF0000 !important;}

I tried to add an image on Shop Page like this. (SHop being the name)
.shop #main-content {background-color: #FF0000 !important;}
But it works for only home page. Please let me know how to add image on a specific page