Whre to find k2 css to modify

I tried to add as you suggested but it does not work((. I called the template demo5 and changed, but nothing. I attach here the file for your review. Many thanks

File

Any news how to make this adjustment? Many thanks again for your help

Hi Esposito, You can place that code anywhere on your css file. You don't have to place it under com_k2.css, but you just need to make sure the paths are correct ( background:url(/deal_plazza/components/com_k2/images/ .... )
Since you're no longer using deal plazza template so you have to change that deal_plazza part in the code with your new template name