For users without Oasis enabled we fire different method instead of SpecialCssController::index(). We do it thanks to [Owen's changes in dispatcher](https://github.com/Wikia/app/blob/82fcc7d1b1bf922ed5427fa3e63a6068338b15da/extensions/wikia/SpecialCss/SpecialCss.setup.php#L29). But it requires F::app(), though...