Navigation - Add contextual navigation on mobile
On mobile we add a hamburger button in the breadcrumbs bar.
When this button is tapped, the sidebar slides in from the left and the content area is darkened. The sidebar can be closed either by tapping on the 'x' button or on the content area.
The sidebar works the same way as in desktop except the dismissive button changes from '<<' to 'x' and it doesn't support the second level fly-outs.
Meta issue #32794 (closed) - Global and Contextual Navigation