2 columns on mobile

Hello,

I’ve been using your plugin for a while an I love it.

The only thing that bugs me is the 3 column display on the phone as well as on desktop.
I ran into some thread where another user explains how to display 2 columns on mobile devices but I can’t find it now.
Could you, please, explain?

I have this code in my child theme’s function.php file:

add_filter( 'the_content', 'add_related_posts_after_post_content' );
function add_related_posts_after_post_content( $content ) {
 
    //check if it's a single post page.
    if ( is_single() ) {
 
        // check if we're inside the main loop
        if ( in_the_loop() && is_main_query() ) {
 
            // add your own attributes here (between the brackets [ ... ])
			$shortcode_1 = '[related_posts_by_tax posts_per_page="6" link_caption="true" title="Related X:" taxonomies="post_tag" format="thumbnails" image_size="medium" orderby="post_date" exclude_terms="5954,21703,16823,16467"]';
			
            $shortcode_2 = '[related_posts_by_tax posts_per_page="6" link_caption="true" title="Related Y:" taxonomies="(custom_taxonomy)" format="thumbnails" image_size="medium" orderby="post_date"]';
			
            $shortcode_3 = '[related_posts_by_tax posts_per_page="6" link_caption="true" include_children="true" title="Related Z:" taxonomies="category" format="thumbnails" image_size="medium" exclude_terms="10530,18894" orderby="post_date"]';
			
            // add the shortcode after the content
            $content = $content . $shortcode_1 . $shortcode_2 . $shortcode_3;
        }
    }
 
    return $content;
}
add_filter( 'related_posts_by_taxonomy_id_query', '__return_true' );