You enable extension and work with your css/less/scss or others.
Styles will automatically update, without reload page.
For start development:
- Install npm modules
 
npm i && cd test-project && npm i && cd ../
- Run 
devscript 
npm run dev
- In first run, need load Extension to Chromium
- Chrome User Menu > More tools > Extensions
 - Click to "Load unpacked" button
 - In file manager select 
extensionsub-folder