This is the modifier pattern to add styles to a component without overriding the existing styles.

PHOTO EMBED

Tue Dec 14 2021 06:40:38 GMT+0000 (Coordinated Universal Time)

Saved by @paulhorowitz 

classes={{
	buttonModifier: defaultClasses.submitButton
}}
content_copyCOPY

This will allow you to add a class selector in CSS called .submitButton coming from defaultClasses while not overriding the existing styles coming from <Button/>