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.

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).