GitHub Pages is currently attempting to load CSS and JS from the root site, i.e yourusername.github.io, and as such it breaks. I removed the root-relative references, and it should work on every site now.
The site title attribute had some logic that would change the site title if a project modal was open, but it caused the title to permanently be set to the title of the last entry in the _posts directory. I removed the if/else logic to keep the site title to be what is specified in _config.yml in the "title" field.
Avonnaire
Kiran
nete-madi
Rodrigo Graça
Jerome Lachaud
basti1dr
Hannes Van De Vreken
Oliver Stapleton