FE - Refactor unused CSS Variables

[marcelluscaio]

There are unused CSS variables. We need to understand if we are going to need them, where the project's theme lives, and keep everything in the same place.

[ajhollid]

Agreed, there are many vars left over from when we switched to using the theme.

I think as a general rule if they're not currently used, they are no longer used at all and can be nuked