I decided to see how this would look like in game but got a crash on loading. Looking at the uploaded jar it seems like you uploaded the wrong one or something.
Inside the jar, the folder structure is:
toughnessbar-1.1/
And inside that folder:

.idea/
assets/
com/
META-INF/
mcmod.info
pack.mcmeta

The .idea/ folder shouldn't be there, and all the other folders should be up one level.

Version: 1.2
https://paste.dimdev.org/iceyeraray.mccrash

oops, there was an issue with 1.0 to 1.2 that it wasn't building correctly because I forgot to run clean. So outside of the dev environment it would crash.