2024-10-03 Purpose of the "@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */" css code? Firefox ・Purpose of the "@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul"); /* only needed once */" css code? | Firefox Support Forum | Mozilla Support・Adding Style Recipes to userChrome.css