Website looks different on other machines

This site should have a red footer. In the settings it has, and two people in different countries see a red footer. I see a black one.

I have cleared the cache and history but it doesn’t change.

A further confusion is that if I look on my phone I see black. My wife’s PS shows black too. My tablet shows black. And my wife’s phone shows black.

I am now working in a different building 1km from my office and it still shows as black. Yet the other people see red.

If it was just my machine I might understand but I see the same result on five other devices, FF and Chrome browsers, and different OS.

Does anyone have any insight please?

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