Responsive Homepage

I am using the Responsive layout with the custom front page under theme options. I changed the width of the container smaller so now it looks awkward because content area and featured content are not the same width. I would like to remove the split frame of the content area and featured content, so that they flow underneath each other instead (like it would look like on a vertical phone/table). I found the #featured section in css but I don’t know what to do. Help? Thanks in advance.
https://nativegroundsf.com