Drop-Down Navigation: Responsive and Touch-Friendly

What if you need a multi-level navigation? In most cases, you design a drop-down menu using unordered lists. But what do you do to make it usable on small and / or cursor-less screens? By usable I mean being able to use hyperlinks on parental anchors and open them with a double-tap (which is a native act on touch devices), also being able to close the drop-downs by tapping anywhere outside them to avoid flashing and other huge usability faults but having a usual bulletproof drop-down menu on desktop screens at the same time.

Here’s a very nice approach and tutorial on how to create a drop-down navigation and making it responsive and also touch friendly.