What started as a toolbox for html/css/js (focusing on CSS viewport units) is now my full-fledged progressive web app toolkit.
This is a zero-dependency project, without any build step. However, you need to serve the public folder. Any http-server will do, e.g.
npm install http-server
./node_modules/http-server/bin/http-server public/https://cssence.com/ - Some rights reserved - CC BY 4.0