Make Navigation work well on mobile

I think the top navigation bar wraps poorly on mobile devices. There's just so many links that they don't fit up the top.

I think it would be great to show an extra level of hierarchy, and moving to a side bar is probably necessary to fit in the hierarchy and show context.

For example, Sphinx docs have a sidebar with a hierarchy, making it easy to go from one page to the next in the hierarchy. Example: the linux kernel docs: https://www.kernel.org/doc/html/latest/core-api/index.html#core-utilities. And on mobile that collapses down to a hamburger menu: