Change Default Font Text and Sizes for Rich Text Box

Summary:

Is it possible to change the default font text and font sizes in the Rich Text boxes when creating a knowledge article?

Content (required):

Our client would like to know if there is a way to change them since the initial text is not that big.

We understand that we can just change it before typing, but they are concerned that there will be some who will not be changing them initially and they may go through changing the size or font of the entire article, disrupting its initial layout.

Version (include the version you are using, if applicable):