Add-on Custom user style


Hi, I was wondering if anyone could make an add-on like this or show me exactly how to do this:

I want to make it so users can set their default font style, including color, weight, font type, size, etc. so that they don't have to keep changing it every time they make a new post. If there is an add-on already for this, please direct me to the appropriate spot.

All help would be appreciated!