You mean you want to add CSS to your extension ? The Frontend
's ->css
extender doesn't work for your case?
You can take a look at the source code of the Frontend
extender to see how you can dynamically insert additional strings to the CSS payload. This allows you to generate less/css content on the fly via PHP and inject it in the forum CSS.
askvortsov there's no need to compile CSS in Flarum. It's always inserted as less and compiled by Flarum automatically.