CartoCSS is a attempt to offer a CSS-like language for GIS and other mapping software.
More information could be found at:
- https://www.mapbox.com/tilemill/docs/manual/carto/
- http://wiki.openstreetmap.org/wiki/CartoCSS
- http://gis.stackexchange.com/questions/tagged/cartocss
To compare CSS and CartoCSS, we can look at the ColorBrewer files: