Something like this should work with the font-weight override. https://superuser.com/questions/318912/how-to-override-the-css-of-a-site-in-firefox-with-usercon

Something like this should work with the font-weight override. https://superuser.com/questions/318912/how-to-override-the-css-of-a-site-in-firefox-with-usercontent-css https://superuser.com/questions/318912/how-to-override-the-c...