CCSS is a command line tool for preprocessing/pretty-printing CSS (Cascading
Style Sheets). It extends the CSS language with support for declaration of
variables and basic arithmetic operations (addition, subtraction,
multiplication, division). The program is supposed to be used as a filter:
it reads the CSS source from stdin and outputs its result on stdout.

While it does not claim to support all the dark corners of CSS, in practice
CCSS handles most CSS found in the wild, including CSS3 constructs. Its
primary advantage over similar preprocessors is speed: the project is
implemented in OCaml, a language renowned for producing native-code
executables of blazing performance.