mkdocs

https://www.mkdocs.org/

MkDocs is a fast, simple and downright gorgeous static site generator that's geared towards building project documentation. Documentation source files are written in Markdown, and configured with a single YAML configuration file. Start by reading the introductory tutorial, then check the User Guide for more information.

Several people on news.yc report using the material theme which does look much nicer than the mkdocs site by default