cssnext is a plugin for PostCSS that modernizes CSS syntax. It transforms modern CSS into CSS compatible with older browsers.
Prior to 2015, CSS was frustrating by not having any specification for features we were looking for. No variables, no math, no color manipulation & no customization. Things are going to change soon since a lot of work has been made by the W3C to write new specs to make our life easier. With cssnext, you can start using some new features today!
In a near future, browsers will implement new CSS specifications. As time passes, cssnext will remove some transformations that won't be necessary anymore. And maybe one day, you will be able to completely remove cssnext from your workflow without touching your CSS.
cssnext uses PostCSS which has a way faster CSS parser. It's a good competitor to libsass, a bit faster than LESS and Stylecow, and way faster than Myth or original Ruby Sass.
The official name is cssnext, which should never be capitalized, especially not at the start of a sentence, unless it is being displayed in a location that is customarily all-caps (such as the title of man pages).
