Using Ghost for documentation

[Kate]

Docs.ghost.org theme

I assume Ghost’s documentation (i.e. https://docs.ghost.org/) is served using Ghost. The theme there is very nice. Does anybody know whether the theme at docs is available on the web? I am especially looking for this: on the left, there is an overall contents menu, and on the right, there is a “on this page” menu. Is there any theme capable of doing this?