Raw link ignored by @import rule if file is hosted on GitLab?

Describe your question in as much detail as possible:
Is it possible to host website source files on GitLab and import them on other websites?

What are you seeing, and how does it differ from what you expect to see?
I tried uploading a dummy css file and I imported it via @import rule into another website to test for changes but nothing happened and it refused to import the new rules. I hosted the same file on another third party file sharing website, used the link and the changes were applied. Can I even use raw links from GitLab in the first place?

What troubleshooting steps have you already taken? Can you link to any docs or other resources so we know where you have been?
I didn’t try anything other than hosting the same file somewhere else to test for wrong rules within