By upgrading to the Personal site plan you can upload your own custom brand fonts to Super and apply them throughout your site.
How to upload your own custom font
First head into the site Design page and then click into Typography:
Then, click into the Primary Font page:
Next, click the upload font button:
Finally, add your font information, choose a fallback and upload the font files as separate weights:
When you’re done, you can simply select the font at the top of the sidebar to enable it as your Primary font, if you wish to apply it as your secondary font, go back into Typography and then into Secondary font.
In this doc: