function applyStyle(css) {
   const ios = Components.classes["@mozilla.org/network/io-service;1"].getService(Components.interfaces.nsIIOService);
   const sss = Components.classes["@mozilla.org/content/style-sheet-service;1"].getService(Components.interfaces.nsIStyleSheetService);
   var cssURL = "data:text/css," + css;
   sss.loadAndRegisterSheet(ios.newURI(cssURL, null, null), sss.USER_SHEET);
   var stylesheetLink = document.createElementNS("http://www.w3.org/1999/xhtml", "link");
   stylesheetLink.type = "text/css";
   stylesheetLink.rel = "stylesheet";
   stylesheetLink.href = cssURL;
   stylesheetLink.charset = "UTF-8";
   document.documentElement.appendChild(stylesheetLink);
}