How to build a developer site like https://ghost.org/docs

I’m looking to build a developer documentation site which has a visual editor and a workflow for non-technical folks. I used Ghost for blogs in the past, and really like it.

I was wondering if Ghost: The #1 open source headless Node.js CMS is developed in Ghost as well (with a custom theme, or SPA). I earlier saw that the Gatsby app powering the docs GitHub - TryGhost/docs: Ghost's official documentation repo was archived.

Would really appreciate any pointers. Thanks!

For that purpose, if you want to try out using Ghost for a Docs site, my current go-to choice would be this theme: