The paths to all resources are missing slashes:

Leading to this result:

Adding slashes by hand fixes everything.

Thanks for the report!
It looks like I broke this on Windows, it's trying to use the Windows separator character \ which doesn't work in HTML.

I have uploaded fixed versions of the mod for 1.16 and 1.17.
I am not able to test on Windows but it should work, please let me know if you have any more issues!

Works perfectly! Thank you :)

Great! Thank you for confirming