Change
Toolbar and address-bar icons now signal hover and active state by colour instead of a background box. Icons stay white at rest, turn light yellow on hover, and take the accent colour while pressed or while their panel is open, the same model FoxOne already uses for tab titles. The bookmark star and the window controls keep their native behaviour.
Fix
On Firefox 153 the address-bar icons that reveal on hover (reader mode, translations, add-on buttons) sat a pixel lower than the always-visible icons. They are aligned again, and Firefox 152 is unaffected.