Gravitons is an extremely lightweight suite of CSS layout utilities based on modular scales and inspired by the Unix Philosophy.

As per Brent Jackson, the original author of the project

We’ve been playing around with our interpretation and came up with even a shorter list of declarations that serves as baseline for all our projects. We did throw in a few colours to align with our global ‘variables’ file that gets adjusted for each project. This makes it very easy to position Bootstrap components and provides the best of both worlds (layout/positioning of built-in elements such as navigation). Very little custom CSS gets needed at the end.

And in case you were wondering, the graviton is a hypothetical elementary particle that mediates the force of gravitation in the framework of quantum field theory.