tkinter - Changing the fontsize for the window and its widgets ?

[R.Wieser]

Hello all,

I've got a small tkinter based program showing (among others) a treeview. 
I would like to set the default font for the whole window to something 
larger, as its supposed to be displayed on a TV a few meters away from the 
user.

A few problems:

1) I have not been able to find any info on how to set the default font for 
the main window (so its caption as well as (I assume, automatically) all its 
placed widgets would than use the new font size)

2) Although I've been able to find how to change the font size for both the 
heading and the items within the treeview, only the heading resizes 
vertically while the items do not (causing the font to be cut-of 
vertically).  Also, the horizontal size of both the the heading and items 
seem to stay the same (do not adjust to the new font size).

Used example code:
https://riptutorial.com/tkinter/example/31885/customize-a-treeview

Regards,
Rudy Wieser