The W3C Schools "Responsive Bottom Nav" seems good place to start.
The Responsive Header also looks like a solution to try.
This seems to be evloving into Master Responsive Design - this the all signing all dancing navigation bar at top and bottom and all responsive.
My preferred choice
This is actually a combination of the Responsive Bottom menu with "accordion" capability if I want it. The template is _botresp.html
- Responsive Web Design
- Sub Footer Menu
- Site Map Development
- Accordion with symbols - This is different to the symbols that I ended up using