Add CSS Variable for Font style/family

Problem/Motivation

Olivero uses a serif font for paragraphs in basic pages using the .text-content selector, although all the rest of my pages have sans-serif. I don't see any way to change it. I even tried using UI Styles to apply Body 1 and Body 2, but that didn't change anything.

Steps to reproduce

Enter a Basic Page with paragraph text in the CKEditor 5 text block.

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes