You mentioned about not being able to "Shift-F2" zoom in in the conditional formatting dialog and thus load NotePad and then copy/paste it back into Access/Conditional Formatting, a fully workable solution.

However, another option, click on the ellipsis, three dots, or whatever you want to call them. It will load the, yeah, I can hear the groans, "Expression Builder". But, in the Expression Builder, you can hold control while using your mouse wheel to increase/decrease font size and type whatever you want then click "OK" (or tab and enter) and Access will paste it for you.