DaffSidebarMode

The various modes that a DaffSidebar can be in. * `side` is a mode that allows you to place the sidebar alongside the content. * `side-fixed` is a mode that allows you want to place the sidebar alongside the content, however the sidebar will scroll separately from the content. * `over` is a mode which allows the sidebar to slide *over* the rest of the content in the viewport. * `under` is a mode that freezes the sidebar in place and allows the content slide above it.