如何在我的Firefox浏览器中将CSS样式表应用于所有页面视图

I would like to apply a CSS stylesheet to all page views in a Firefox browser using a menu option and be able to toggle this when required. (The functionality I want exists in IE: Tools | Internet Options | Accessibility | Format Documents Using my Stylesheet (although I think this may affect pages outside of simply IE).I would like to apply a CSS stylesheet to all p