This is the same color that the Dash currently has, except
it isn't transparent.
The reason for this change is that the app grid coming from
the bottom and passing below the Dash looks odd with the
transparency there.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1593>
Only the area used by favorite apps can be used as drop targets, it
is not possible to add new favorites between the running apps at the
end. While that behavior makes sense, it is currently impossible to
distinguish the two areas with confusing results.
Address this by adding a visual separator between favorites and
running apps.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1606>
And move it to the bottom of the overview. Change the height-based calculation
of the icon sizes to be width-based. Put the DashFader in a vertical box, and
make all corners of the Dash equally rounded.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1559>