MkDocs
Project documentation with Markdown
... on the MkDocs Themes wiki page, or build your own. Get your project documentation looking just the way you want it by customizing your theme and/or installing some plugins. Modify Markdown's behavior with Markdown extensions. Many configuration options are available. The built-in dev-server allows you to preview your documentation as you're writing it. It will even auto-reload and refresh your browser whenever you save your changes.