Ask HN: User Documentation solution?

I have to make a "microsite" under my application with documentation about it.

The concept must be very similar to any "programming project" style.. (codex.wordpress.org, guides.rubyonrails.org, docs.shopify.com/themes): I have to teach users how to do some tasks.

I started generating Markdown files and parsing them as html but I realized that the scope is a bit larger: I have to handle sidebar links, breadcrumb navs, translation support, etc)

Is there any tool/service/project for that? What is the best/common practice to solve it?