private function _inlineStyle($data = null) {
        // no data?
        if(is_null($data))
            return false;

        // fix paths
        $data = $this->morph($data, function($url) {
            return $this->Url->build($url);
        }, '/^(data:|https?:)/');

        // compress
        $data = Algorithms::css($data, $this->_config['config']['css']);

        // keep a reference to avoid duplicates
        $hash = md5($data);
        if(in_array($hash, $this->inline['css']))
            return false;
        else $this->inline['css'][] = $hash;

        // output
        return "<style>{$data}</style>";
    }