This is a derivate of the Auto hide sidebar style http://userstyles.org/styles/1633 in combination with the code moving the sidebar to the right, which i got from http://userstyles.org/styles/510
The number for margin-right (in #sidebar-box) needs adjustment to the width of your sidebar that you had before installing this style. You can do this by playing around with it and hit "Preview" untill it works :-) or you can find out the width via DOM inspector. See the page for the original style http://userstyles.org/styles/1633 for an explanation.
Also the number for margin-right (in #sidebar-splitter) might need a little adjustment depending on your theme...
A restart will be needed after first activating this style...
Have fun!