Make sidebar navigation mobile friendly
Currently, the sidebar navigation is not mobile-friendly on all devices.
On the iPhone X, for instance, the menu cannot be opened/closed.
To solve this we can refer to the sidebar navigation layout in gitlab.com
- Add a hamburger toggle to the top left.
- Collapse the menu completely (get rid of the grey gutter when collapsed).
x Close sidebartoggle to the menu when expanded.
- Add a grey overlay to the content behind the menu when expanded.