Flat buttons look the same when pressed
Current behavior
On latest Adwaita theme (in GTK 4.0.0), toggle-able buttons with "flat" CSS class look exactly the same when pressed.
This is how unclicked button inside GTK Inspector looks like (in CSS tab):
And this is button (left one) in pressed state:
The only way to tell that it is pressed is to lose focus on app window:
Expected outcome
Clearly see that the button is pressed without the need to lose focus on app window.
Version information
GTK 4.0.0, Linux, gnome-shell, Wayland session