Theme Businesso Width Issue

Hey everyone!

my problem is the following:

The width of my pages are at 75%. I am trying to increase them to 100%. I do not want to use the side bar. I have tried to use the “blog-full-width” template but it is not working.

With Firebug, I found the little code to modify:
.col-md-9 {
width: 75%;
}

Unfortunatly, when I change it in my child theme, it doesn’t work.

I tried to deactivate all the plugins, clear my cache and nothing dows the trick.

Anyone have any suggestion?

Thank you in advance! ??

site: https://conception-web.ca/sites-internets/