How to build GitLab style documentation

I love how GitLab Docs looks, feels, behaves, as in here -

GitLab Docs has been migrated to use nanoc and there is a GitLab Pages template for creating a nanoc site - but the two are almost nothing like each-other.

What I’m trying to do is how to customize the nanoc site so that its structure resembles that of GitLab and by that I mean - sidebar, header & footer, page layout.

I looked into the repo but I can’t find anything remotely resembling the structure of nanoc.

Thanks and have a good day :slightly_smiling_face: