Backround color of Body of Page

Hello!

I cannot figure out how to change the body color of a page I am working on. For instance in the menu of “everything ocean”, I want it to look exactly like the coming soon post, with a white body but the background behind it. It is too hard to read how it is now.

Help me! Im very new to this so I have no idea where to even start.

https://asthepalmtreeturns.com/?page_id=379