Document what font should be used

[0xfalafel]

Problem

I am creating an app. And I don't really know what fonts I should use in the app.
This isn't covered anywhere in the documentation as far as I can see.

Proposal

It would be nice if the text section of the documentation talked a bit about:

• what font should be used
• what is the recommended size
• are they CSS class that should be used

Prior Art (Optional)

The iconography does a good job of documenting how things should look like.

[danirabbit]

Fonts are automatically set in GTK. There's no need for you to manually change fonts in your app :)