After I upgrades my OS X system to Catalina, the fonts in the help panel and in vignettes changed from a sans serif font (ariel?) to a Times-type serifed font, which I find much less attractive. It is as if the CSS that RStudio uses to display help files and vignettes changed. Where would such that CSS be located, and why would it have changed upon upgrading OS X to Catalina?
RStudio edition: 1.2.1335
R version: 3.6.1
OS version: was OSX 10.14.something, now 10.15.1