On the very core of Monogatari, you'll find it has been built around the Aegis Framework libraries.
These libraries are used both for functionality and styling so learning more about them will allow you to create even more amazing things!
Artemis is used for DOM manipulation, storage, HTTP requests handling, text transformations and more!
Kayros is the very base of Monogatari's style and look!
Pandora is what allows monogatari to have self contained, custom HTML elements and allows them to have custom functionality.