Every change in UI (css etc.) takes 20-30 sec to fully reload server and client. How to make it quicker?

How to develop UI quick? Right now server and client reloads after every change 20-30 seconds (core i5 16GB). It’s unusable for quick development.

Thank you!

CSS update also does not work with live reload. I need to reboot server manually every time I change something in CSS to see changes. What is proper UI-development workflow?