How to override website fonts?

Description of the issue:
I want all websites to use a certain font (arial black)
Steps to Reproduce (add as many as necessary): 1. 2. 3.

Actual Result (gifs and screenshots are welcome!):

Expected result:

Reproduces how often:

Operating System and Brave Version(See the About Brave page in the main menu):
mojave 10.14.6 brave 1.19.86
Additional Information:
is there any way to do this? In settings I have the fonts set to arial black but the websites still display there native fonts.