CSSrefresh is a small javascript library that monitors the CSS-files included in your webpage. Within 1 second after changing an included css file the style changes are applied to the webpage without reloading the browser.
This project is inspired by http://cssrefresh.frebsite.nl/, but rewritten from scratch as I couldn't find any github repository or twitter profile to communicate the issue that made it not working for me anymore.
<body>
<script async src="https://it-ony.github.io/cssrefresh/cssrefresh.js"></script>
</body>
or visit https://it-ony.github.io/cssrefresh and drag the bookmarklet to your bookmark bar.