public function registerStyleAsset($path, $type = null, $media = null, $rel = 'stylesheet')
    {
        if ( ! array_key_exists($path, $this->styleAssets)) {
            $this->styleAssets[ $path ] = [
                'type'  => $type,
                'media' => $media,
                'rel'   => $rel,
            ];
        }

        return $this;
    }