protected function loadCss($css, $options=array())
    {
        $location = (isset($options['location'])) ? $options['location']:'internal';

        //after:file, before:file, first, last
        $position = (isset($options['position'])) ? $options['position']:'last';

        if(!in_array($css,$this->data['css'][$location])){
            if($position=='first' || $position=='last'){
                $key = $position;
                $file='';
            }else{
                list($key,$file) =  explode(':',$position);
            }

            switch($key){
                case 'first':
                    array_unshift($this->data['css'][$location],$css);
                break;

                case 'last':
                    $this->data['css'][$location][]=$css;
                break;

                case 'before':
                case 'after':
                    $varkey = array_keys($this->data['css'][$location],$file);
                    if($varkey){
                        $nextkey = ($key=='after') ? $varkey[0]+1 : $varkey[0];
                        array_splice($this->data['css'][$location],$nextkey,0,$css);
                    }else{
                        $this->data['css'][$location][]=$css;
                    }
                break;
            }
        }
    }