How to add CSS files on a Sylius theme?

I’ve a custom theme under app/theme/AcmeTheme. I have the theme working and I can define my own templates under views or override template for other Bundles. The problem is that I can not figure out how to add a custom CSS file inside my theme. So fat I’ve tried:

AcmeTheme/public/style.css AcmeTheme/web/style.css

But after running assets:install and sylius:theme:assets:install the file is not copied. I have read the documentation multiple times and I can still not get it to work.