Hi,
Indeed, this listing_div view file is used for all the products listings, including the related products one.
So if you want your hard coded classes to dynamically change, you'll need to write some more complex code.
For example:
<?php
$class = 'hkc-lg-3 hkc-md-4 hkc-sm-6';
if($span == 2) {
$class = 'hkc-lg-2 hkc-md-3 hkc-sm-4';
}
?>
<div class="<?php echo $class; ?> hikashop_product hikashop_product_column_<?php echo $current_column; ?> hikashop_product_row_<?php echo $current_row; ?>"
This means that based on the number of columns selected in your menu item / module, you can change the classes being used.
Here, you can see that it will use hkc-lg-3 hkc-md-4 hkc-sm-6 for all the products listings, except if the current number of columns is set to 2 in the settings, in which case it will use hkc-lg-2 hkc-md-3 hkc-sm-4
So it's up to you to adapt these based on what you need.