The shortcode

<?php

add_shortcode('myplugin','myplugin_shortcode');
/*   [myplugin category="0" order="ASC" orderby="date" post_not_in="233" limit="4"]

 * - category (default = all)
 * - limit (default = all)
 * - showimage (default = true)
 * - imgwidth (default = 300)
 * - tags (default = none)
 * - sticky (default = false)
 * - filter: latest, random, [popular] (default = latest)
 *
 * - order: (default = date)
 * - orderby: (default = DESC)
 */
function myplugin_shortcode($atts,$data = '')
{
    echo '<link rel="Stylesheet" type="text/css" href="'.plugin_dir_url(__FILE__).'style.css">';
    global $wpdb;
     $limit = $atts['limit'] ? $atts['limit'] : 0;
        $imgWidth = $atts['imgwidth'] ? $atts['imgwidth'] : "80";
        $showImg = $atts['showimage'] == 'false' ? false : true;
        $columns = isset($atts['columns']) ? $atts['columns'] : '4';
        $args = array(
                'cat' => $atts['category'],
                'category_name' => $atts['slug'],
                'tag' => $atts['tags'],
                'post_type' => 'post',
                'posts_per_page' => (isset($atts['limit']) ? $atts['limit'] : 6),
        'order' => $atts['order'],
        'orderby' => $atts['orderby']
        );
        $wp_q = new WP_Query($args);
        $ResponsiveCounter = 1;
        while($wp_q->have_posts())
        {
        $wp_q->the_post();
                $post_class = '';
                if($ResponsiveCounter == 1)
                        $post_class .= ' left-fit';
                if($columns == '4')
                        $post_class .= ' grid col-220';
                else if($columns == '3')
                        $post_class .= ' grid col-300';
                else if($columns == '2')
                        $post_class .= ' grid col-460';
                if(($columns == '2' && $ResponsiveCounter == 2) || ($columns == '3' && $ResponsiveCounter == 3) || ($columns == '4' && $ResponsiveCounter == 4)){
                        $post_class .= ' fit';
                        $ResponsiveCounter = 0;
                }
                echo '<div class="'.$post_class.'">';
        $id = $wp_q->post->ID;
                $myimage_html = '';
                if($atts['hidetext'] == 'true')
                        echo '<li><a href="'.get_permalink($wp_q->post->ID).'">'.$wp_q->post->post_title.'</a></li>';
                else
                        echo '<div id="nw_post_'.$id.'" class="plnaslov"><a href="'.get_permalink($wp_q->post->ID).'"><h4>'.$wp_q->post->post_title.'</h4></a></div>';
                if($showImg)
                        $myimage_html = my_get_first_image($id);

                echo '<div class="plcontent">';
                if($myimage_html != '')
                        $myimage_html .= '<br>';
                echo $myimage_html.get_the_excerpt();
                echo '</div>';
                echo '</div>';
                $ResponsiveCounter++;
        }
}