External CSS Problems/Limitations

I would like to know if there are any alternatives on how i may be able to add my own CSS to the project.

Currently my custom CSS has exceeded over 20k chars so i am unable to add more to it. The only way i now know is to add external CSS. I currently don’t have any place to host it.

I did try github gists but then ran into CORS issues.
Do i need some sort of JS that brings the code in, if so can anyone share a working snippet?

I did try searching the forums, the solutions present aren’t implementable due to the new browser policies like CORS.