Module Class Not Being Applied

I am using the PagePeel Banner module on a site for a client. I added a css class in the Module Class Suffix in the Advanced tab, and the class is not applied in the code. The following code was added in the module:This class uses media queries to determine the screen width and makes the associated content visible only if the width corresponds to smaller mobile devices (phones only, not tablets or desktops). I can add the class to the page-peel-banner div manually in Google Development Tools (or Firebug) and it works fine, but it should be added by virtue of the data in the Module Class Suffix. Please advise.

I should clarify that only the part in quotes of the code snippet above is present in the Module Class Suffix textbox.