Dear nicolas, thank you for the answer.
Unfortunately the rule does not apply and the category name text doesn't change in red color: all other types of customization seems to works fine.
It' s very strange....
I know is not the right way to work, but I also tried to apply the class directly in the listing_img_desc.php file
Code:
<!-- CATEGORY NAME -->
<span style="color: red;">
<a href="<?php echo $link;?>">
<?php
echo $this->row->category_name;
if($this->params->get('number_of_products',0)){
echo ' ('.$this->row->number_of_products.')';
}
?>
</a>
</span>
But same result.
