div content not responsive

I'm working on a site that was developed by another person. This site is designed with wordpress by override a base theme(blankslate). This is the link: http://www.good-look.it There is a problem. When you resize the browser window you can see that the div with white background is responsive, but its not. On mobile the problem is more visible. I can't find a solution. Maybe is a problem with the plugin that manage the image slides(NextGEN Gallery by Photocrati)?