Scoped stylesheets are no longer supported | Firefox Site CompatibilityThe support for HTML scoped stylesheets, implemented with Firefox 21, is no longer available in web content because it has been removed from the HTML spec. This includes the scoped boolean attribute on the <style> HTML element, the scoped DOM property as well as the :scope CSS pseudo-class. Google Chrome has already removed the implementation and no other browsers support the feature at this time.
