Adding a submenu in navigation

I created a responsive navigation menu with a tutorial in Hongkiat. http://www.hongkiat.com/blog/responsive-web-nav/ (http://www.hongkiat.com/blog/responsive-web-nav/)
In that tutorial there is no sub menu items. But I want to add a submenu.

This is the demo I created in JSfiddle. http://jsfiddle.net/viveknath322/3AHTg/1/
In that demo I want to add submenu in Tools menu. Its very helpful if you modify that code in Jsfiddle.
Any help will be appreciable:).
Thanks.
Regards,
Vivek Nath.

If you created that yourself, this tutorial on a 2-level menu should be a piece of cake for you: (linked from my signature page).