What is the best way to manage fontSize in a react / react-jss website: centralized or decentralized or?

Wondering how other folks do this?

I have a website in reactjs + cssinj/react-jss and I manage all the colors and using themes. Also, I am using Material UI, so this is easy. The only thing that I am struggling with is the fontSize. I have tried centralized variables, but does not smell as best option, I kinda getting back to a lot of customizations. Now, I am trying to add a decentralized form by using fonts at the components level, but I am worried if this is going to smell good when I am done with all the changes.

Any thoughts or opinions?