Thank you for your reply!
1. the css code to change the color of the footer background : maybe I am using the wrong word to describe my footer color, but to me it is still grey and I have not manage to change it to white.
2. the css code to reduce the width of my footer : I need a very thin footer – Thank you for the CSS code. But now I have to understand where to add it (see below).
3. and the right place to add this css code: is it possible NOT to create a child theme and add the modifications directly on the Pictorico original theme? If yes, where should I add the CSS code you gave me?
Globally, I am confused with the place where I should add all the codes :
> When I click on Footer.php for example, where is the exact place I should add the code? Which line?
> Is it possible just to add the code on Simple Custom CSS and expect the code to work?
Thank you SO much for your help.