Change WPFolio theme to fixed width

I am using the WPFolio theme in this site: https://www.alphabetsoupgroup.com/Kim/ . On smaller screens or when I reduce the size of the window, the side image in the background is covered by the content. I originally thought that my problem was that this was a flexible width theme so I tried this: https://www.ads-software.com/support/topic/how-do-i-change-fluid-width-theme-to-fixed-width?replies=4. Nothing seemed to change, although I may have done it incorrectly. Should I be concentrating on a min width?

I appreciate any help.