Product listing display different between desktop, tablet and mobile mode

-- url of the page with the problem -- : www.kamagraerektion.info/
-- HikaShop version -- : 3.0.1
-- Joomla version -- : 3.7
-- PHP version -- : 5.6.30
-- Browser(s) name and version -- : Firefox 51.0.1

Hello,

On this moment the display in desktop and tablet (landscape mode) mode lets see 4 product at a row and in tablet and mobile mode the display lets see 1 product.

I want it to be as follow.

desktop mode (4 products)
tablet landscape mode (4 products)
tablet portrait mode (2 products)
mobile portrait and landscape moede (1 product)

How do i manage this.

Oke Nicolas,

I changed the code (in the listing_div file of the protostar template that is used).

Now the code in that area of the file is:
<div class="hkc-md-<?php echo (int)$span. ($span==3 ? ' hkc-sm-6': ''); ?> hikashop_category hikashop_category_column_<?php echo $current_column; ?> hikashop_category_row_<?php echo $current_row.$class; ?>">
<div class="hikashop_container">
<div class="hikashop_subcontainer <?php echo $borderClass; ?>">

But nothing is changed, do i need more thing to do to to get it the way i want it?

Yes, you rigt, i put it into the catogory.

i fix that and change the product.

now it works fine.

THX