Unfortunately not. And I hadn’t time to investigate it any further.
My latest guess was, that we have to modify a config file of the apache webserver. It seems that apache doesn’t send the css files with the right mime type.
Further investigations. The Response Headers tells me X-Powered-By: PHP/5.5.31. So the Problem comes not from the apache but a PHP configuration - I guess.
Fix for this is coming in the next release.
May already be available in the develop branch of the repo – just know that the dev branch is not fully tested for stability (hence why it’s not released officially yet.)