//Open the file directly in the browser and run this script from the console //Assumptions: The browser uses a <pre/> tag for showing the CSS code var file = document.querySelector("pre"); var fileContent = file.innerHTML; var newContent = fileContent.replace(/([\d.]+)(rem)/g, function(m){ var measure = parseFloat(m.split("rem")[0]); var newMeasure = measure / 1.6; newMeasure = newMeasure.toFixed(2); return newMeasure+"rem"; }); file.parentNode.innerHTML = "<pre>"+newContent+"</pre>"