Sitecore SXA CLI how-to: compile and minify CSS at the build server

During the last few weeks I worked a lot with SXA themes and the thing I was concerned about was: storing CSS/JS files in media library / serialization.

Well, there is nothing wrong with media library and it is extremely useful for distributed setups, but pushing compiled (or even minified) files to GIT just to make sure they will be added to the deployment package seemed painfully wrong.

Additionally, it caused merge conflicts when multiple people worked on front-end part of the site.

Luckily, it is not complicated at all to change that while maintaining typical delivery workflow. What we need to do is:

1. Compile / minify .SCSS into .CSS at the build server
2. Convert compiled file (i.e. *-min.css) into the .yml
3. Package .yml into update package (trivial with Sitecore Courier)