Page does not apply css, css file is loading

I have been making some progress in transitioning a full HTML page to Github Pages + Jekyll. I have noticed however, that when going to the github domain version of the site the CSS does not get applied, while the CSS DOES load when inspecting the network tab.
image

I do not seem to have this issue when running in the development environment, and I can’t figure out what is causing this to happen. It happens on multiple machines and browsers, so I don’t believe it is a caching issue (I have waited ~8 hours).

Because I can’t post more than two links at a time, I had to split this up…

As an example of what the site is supposed to look like, see here, and the Github Repo in question is located here, I appreciate any assistance.

If it is any reassurance. I have double checked that url’s don’t have a leading /, that the pages don’t have leading _, have confirmed that they are actually present (can also be determined from the original picture).