Remove "Category" from page title

HI everybody

on my category page would like to make the heading "Category:" disappear and only leave the category name.

Here, for example:
http://riccardocavaliere.com/category/reportage-e-descrizioni/

THe title of the page is "Categoria:Reportage e descrizioni".

I only wanna have "Reportage e descrizioni" and remove "Categoria".

How do I do?

BY the way, I'm using a child theme. Is there a code I could write in the Custom CSS?
Thanks in advance!