It's a front-end framework that makes it much easier and more pleasant to create beautiful adaptive web-sites
MCPVR stands for (M)aterial (C)olor (P)alette and (V)ertical (R)hythm.
As you could guess it has pre-defined color palette and all it's elements are aligned to the baselines.
MCPVR is written in SASS (ans JavaScript ofcourse) and any part of the framework can be used separately