Fonts are changed and override BTTV settings

[twelfthdoc]

Twitch uses the font Roobert as its default font, whilst before the rebranding strategy it previously defaulted back to Helvetica Neue, Helvetica, Arial, sans-serif in order.

I've found that the app breaks or overrides the new default font and replaces it with Arial. The font change is a sharp contrast and a little hard on the eyes for those used to the wideness of Roobert and Helvetica Neue's characters.

Occurs on Firefox 84.0.2 on the dev build.