Susy is a semantic CSS framework creator entirely native to Compass.
Susy is an expert at fluid grids in an elastic (or fluid, or fixed)
shell that will never activate that bloody side-scroll bar. Susy
sets your width on the outer element (`container`), adds a `max-width`
of `100%` and builds the rest of your grid in percentages. The
philosophy and technique are based on Natalie Downe's "CSS Systems"
- which introduces difficult math in the service of beautiful
structure. With the power of Compass/Sass, Susy will do that math
for you.

Using simple mixins, columns can be created, suffixed, prefixed,
and nested easily - and always in flexible percentages.