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Hi, Saijo and Bradley are right in saying that hiding elements on a smaller screen should not be an issue (as it's a correct implementation of responsive design). Bear in mind as well that there is a Googlebot and a Smartphone Googlebot, so as long as the Googlebot is seeing what desktop users see and the Smartphone Googlebot (which uses an iPhone5 user agent) is seeing what mobile users see, it shouldn't be a problem. The only thing I would add: If you are going to use display:none to prevent a user from seeing something when they view your site, it's good to include an option to 'view full site' or 'view desktop site'. Also in that case I would question whether you actually need that content on the desktop site at all? Because best practice is to provide all the same content regardless of device. If it's hidden but still accessible to the mobile user (in a collapsible div for instance) there's no cloaking involved so it shouldn't cause a problem. As a side note: the Vary HTTP header is really for a dynamically served website (that is, a single URL which checks user agent and then serves the desktop HTML to desktop devices and mobile HTML to mobile devices). Hope that helps!