support nested menus

[jjroelofs]

Thanks for your awesome menu, I was looking for a mobile dropdown solution to integrate in my Drupal theme. This menu was the only menu that I thought was delightful to use.

The difficulty with the CSS in the menu is that it doesn't work with an HTML structure of nested menus, which is what most websites use and is difficult to produce, especially when in desktop view the website uses more traditional dropdown styling.

To make a start with integrating the menu in my theme I had to make the following changes:

• use position fixed so that nested menus are positioned independently from parent menus
• rewrite translate3d animation to margin-left because translate CSS creates nested reference frames that don't support fixed positioning relative to the viewport
• Reduced the "back" animation to 0.1 because I can't make it work smoothly without breaking something somewhere else