CSS Styles not Updating with Upfront

Hello,

I'm having a weird issue with the css styles in Upfront. Some of the changes I am making in css are showing up on the site, but not in my upfront view and other changes are only appearing in my upfront view.

I've created a screenshot that illustrates the problem. The first image is my site when I'm logged out of the upfront customizer. The second image is my site when I'm logged into the upfront customizer.

The text styles are only appearing correctly within the upfront customizer. This is best illustrated with the H1 text that appears at the top (Angry Tiger).

Hyperlinks are only appearing correctly when I'm logged out of the upfront customizer (they are supposed to be the dark red).

I've already tried deleting my web cache/history.

What could be causing this?