How does it know a file has changed? It constantly reloads it?<p>For a less magical tool, there's <a href="https://www.npmjs.com/package/instant-server" rel="nofollow">https://www.npmjs.com/package/instant-server</a>, which acts a simple HTTP server, but reloads your CSS whenever it changes without refreshing (it also refreshes on JS or HTML changes, but nevermind).