Concise is a project that I worked on for 300 hours over the course of late 2013 to July of 2014. What was originally a tool for me to use on personal projects turned into a full-fledged front-end framework dedicated to providing an alternative to all of the large and bloated frameworks in existence.
True to it's name, Concise attempts to provide a lot of features and functionality in a relatively small amount of code and without having to override styling constantly. Within Concise there is beautiful typography, a flexible grid system, responsive navigation and so much more.
Concise is built from the ground-up to be mobile friendly and was originally written in SASS. Concise now has an officially maintained port of both LESS and Stylus, and is always keeping up-to-date.