ThemeA Theme object represents the specification of a theme.TypeA JSON object that takes the same properties as the "theme" manifest key.Browser compatibilitydesktopmobileChromeEdgeFirefoxOperaSafariFirefox for AndroidSafari on iOSThemeNo supportChromeNoToggle historyNo supportEdgeNoToggle historyFull supportFirefox55Toggle historyNo supportOperaNoToggle historyNo supportSafariNoToggle historyNo supportFirefox for AndroidNoToggle historyNo supportSafari on iOSNoToggle history