Bludit Flat File CMS
Pi Lab is powered by Bludit.
Bludit is an amazing Flat File CMS. There is no database to configure!
With a full featured plugin and theme system the ability to fully customize your setup is truly amazing. It is SEO friendly. It supports Markdown and HTML for your content and includes a Markdown Editor and WYSIWYG Editor.
If you are looking for a powerful and lean CMS I highly recommend Bludit.