Jake Archibald introduces how making simple changes to Service Worker can vastly improve the startup and load performance of your web site. In this video Jake shows how he has made his Wikipedia application not only work offline but amazingly performant too.
Jake, in his typical Jake style. Love that guy!
One might argue that this is quite some overengineering as you need to pull in the ServiceWorker et al. If you want to keep it simple just unblock your JS and CSS, it’ll knock off quite some load time without an extensive amount of work / needing to learn a new technology.