Reduce body width.

I found the page below while Goggling about my query. (dated 2014). https://catchthemes.com/support-forum/topic/increase-body-widthdecrease-sidebar-width/ However I would like to REDUCE the width. I played around with the code on that page as Sakin suggested but the wrapper is still sized at 1280px. in the parent theme. I played around with that too but no joy. I would like a width of 1024px. The site I'm working on is: http://cs006.info/classicsites.co I thank you in advance. Brian