Default font for TimeLine notes

Hi,

I have a requirement to change the default font for the Case Timeline Notes section, is this possible? I have located the below post(s) and we are already using the rich text editor but I cant see where to set a default font for the users for this form. 

https://powerusers.microsoft.com/t5/Building-Power-Apps/Default-font-for-timline-notes/td-p/617231

Thanks