CSS Minifier and Utility Library

Crass is a JavaScript utility library designed for CSS minification, pretty-printing, and general manipulation. Unlike many other CSS minifiers that operate on string-based transformations, Crass constructs a full parse tree of the CSS, enabling deeper and more accurate optimizations, particularly for gzip compression, and consistent pretty-printing. It supports CSS3 and CSS4 features, with options to strip obsolete tags based on browser versions and convert colors to their smallest forms. The current stable version is 0.12.3, last published in February 2018. The project is no longer actively maintained, making it an abandoned library. Its primary differentiator is its parse-tree approach, which, while slower, allows for advanced optimizations not possible with string-manipulation tools.