How to set the font style and font size of the title text?
Titles display in the viewer window are activated in
File > Preferences > Appearance
and setting the flag at "Titles"
The font type and size can be modified with the following commands in the TUI.
For the font choice:
(cxsetvar 'frame/title/font "name=Segoe UI") (could be roman, calibri, etc)
For the font size (0.2 is the default):
(cxsetvar 'frame/title/font (format #f "size=0.4wru"))