About a year ago I posted a link to a collection of npm packages for use on the command-line, collectively called `themer`[1]. This link is to an offline-capable Progressive Web App that wraps the CLI packages and adds the capability to not only generate the themes but to more easily create your own set of colors with a tight feedback loop.

The PWA is open source[2] (as is the CLI, of course), features no ads/trackers/analytics (supported solely by Brave Rewards/$BAT), and takes advantage of PWA features like caching for offline use.

Hope you enjoy!

[1] https://news.ycombinator.com/item?id=16021874 [2] https://github.com/mjswensen/themer