[Basic Theme – Themify.me] Disable fluid layout

I made a child theme from Basic Theme from Themify.me, and this layout is fluid, prepared to smartphones and other devices. I need to disable this fluid behaviors, I′ve already tried to contact the support, but any answer. How Can I disable this feature? I know that It uses this code “css3-mediaqueries.js” but I don′t know how It affects this behavior. I tried to change many css styles from % to px, but without results, any help please?

Thanks a lot!