Disable cleanCSS

cleanCSS destroys my layout (if there’s a footer and a header on page it adds unnecessary margin-top to the footer, that is almost 500px so the whole page is obstructed), I tried working around that, yet failed.

I need to deploy the app pretty soon, so I need to disable the cleanss task in build --prod (when I manually deleted the lines in build.js in app_scripts, it works fine). What should I add to my webpack.js?