How to add a custom theme

I found some less files for themes, e.g.

How would one add a custom theme (that’s ideally also being built like that using less)? Is there a convention for adding it to sth like custom/themes perhaps?

I have not try it yet, but from what I’ve read on the documentation here , you could add custom css on the page header or just link another css file which could be put on custom/public/ directory ( . Hope that helps

Ah, so I would put a custom/public/css/theme-my-theme-name.css then I guess? Worth a try.