Website Branding Guidelines

I'd be grateful for clarification of site font / structure guidelines as related to the fonts / headings et al in the FTH admin console. The branding manual on p. 16 describes the use of the Gotham font, but 1st, I see no link to download it (I did download Monstserrat), 2nd, what is the equivalent(s) in FTH?

I'd love to  get any insight someone can offer.

If I recall correctly, the older brand manuals specifically mentioned Arial as an acceptable website font
Currently there is a note on p18: "Arial is a tertiary font for body copy that comes standard on most systems".

Arial is available in the third-party editor used by FreeToastHost.