Page background won’t display until I click on it

I am having this problem on every page of my website – when I go to the website only the header and some of the text displays until I click on the page (or touch the screen on a device). It’s like the background isn’t loading properly. I am a bit of a novice WordPress user, can anyone help or give simple advice of how I can try and fix this?

The page I need help with: [log in to see the link]