Having decided to keep Ambiance as the default GTK theme in Ubuntu 17.10 it was only a question of when devs would extend the gradated brown palette to the rest of GNOME Shell.
In an update today they’ve delivered one.
GNOME Shell Ambiance Theme
In GNOME Shell you have a GTK+ theme, which handles the appearance of apps, dialogs, modals and so on; and you have a GNOME Shell theme, which controls the appearance of the top bar, shell menus, alt+tab and the overview screens (it is literally the shell theme).
This is what the stock, vanilla ‘GNOME Shell’ theme looks like on Ubuntu 17.10:
And this is what the new GNOME Shell Ambiance theme looks like:
You’ll notice that the top bar is a brown gradient instead of solid black, while the sliders, toggles, buttons and accents in the Status Menu are now orange instead of blue.
These bright accents and highlights extend to the activities overview too:
Activities overview: manage running apps and workspaces
In upstream GNOME Shell 3.26 of the bits that are orange in the screenshots above are blue.
In GNOME Shell 3.26 the top bar is transparent by default. It turns solid when an app window is maximized.
Sadly the new Ubuntu Dock also hasn’t quite managed to ‘match’ the transparent top bar, as these screenshot shows. The transparency effect of the dock is also spoilt slightly by the solid right-click menus:
Naturally the alt + tab switcher is also given some Ambiance-colored attention:
Don’t panic if this new GNOME Shell Ambiance theme isn’t exactly to your tastes. GNOME Shell makes it pretty easy to install and use different GNOME Shell themes, like the (gorgeous) United GNOME theme.