CSS minification and bundling replaces 0px with 0 in calc, so content doesn't render properly

Question

I'm using Microsoft.AspNet.Web.Optimization (1.1.3) from an MVC 5.1 site to bundle and minify my CSS and it is replacing values of 0px with 0 in release mode and this causes rendering issues. Is it possible to stop this behavior somehow?

This css

min-width: -webkit-calc((240px + 0px + 550px + 0px + 240px + 0px));

Is replaced with:

min-width: -webkit-calc((240px + 0 + 550px + 0 + 240px + 0));

Answer 1

Given that the css is already minified when Compass compiles the SASS to CSS, I have opted to remove the transforms.

private static void DontMinifyStyleBundles(IEnumerable<Bundle> bundles)
{
    // SASS is already minified by compass at build time and the default asp.net minification 
    // causes 0px in calc() to be set to 0 which causes rendering problems.
    foreach (var bundle in bundles)
    {
        bundle.Transforms.Clear();
    }
}