text: // dependencies
  var fs = require("fs")
  var postcss = require("postcss")
  var customProperties = require("postcss-custom-properties")
  var calc = require("postcss-calc")
  
  // css to be processed
  var css = fs.readFileSync("input.css", "utf8")
  
  // process css
  var output = postcss()
    .use(customProperties())
    .use(calc())
    .process(css)
    .css
  