Minimalist Theme Edit

My site is: http://radicalundoing.com

Click once to enter the page.

When I make my browser window smaller, the central column tracks to the left and then falls underneath the menu.

How do I make it work the way it does on these sites:

http://23nine.com/blog/
http://www.nobukoakiyama.com/
http://instantrecords.com/

Notice that when you make the browser window smaller, the central column does not drop below the left menu. It stays flush with the blog title.

Thank you.