You should set up your GitHub repo differently, it should be in your root mod folder (the one right above /src/)
Your repository is currently missing the files needed for someone else to download and set it up.
Here’s an example of a properly set up repository (notice the build.gradle file) https://github.com/Cadiboo/Example-Mod.
I think you should put a breakpoint in loadColor in your block class, and see what color it returns and why. As a programmer you need to know how to use the debugger, it’s an extremely helpful and powerful tool and there are plenty of online tutorials about it.
Because you were using a TE, I assumed you were using a TESR. It’s good that you’re not though