fixed typos in css class name
fixed typos in css class name

brianjking/html5-device-mockups,wleopar-d/html5-device-mockups,palimadra/html5-device-mockups,ddeveloperr/html5-device-mockups,pixelsign/html5-device-mockups,DockDogs/html5-device-mockups,francknij/html5-device-mockups,wgarcias2015/html5-device-mockups,pixelsign/html5-device-mockups,palimadra/html5-device-mockups,MinxianLi/html5