The menu bar across the top of the display - it’s been blue, and suddenly it’s a light orange, and the name of the application at the top left is shaded in grey.
Why would that happen?
That’s interesting. No idea. Mine is the default grey. How the hell did you do that?
You have ‘Translucent menu bar’ checked (System Prefs/Desktop and Screen Saver/Desktop). And your wallpaper changed from something blueish to something orangeish.
four minutes from OP to correct answer - thanks, tellyworth!
Mrs Piper changed the wallpaper, which happened to have a grey bar right in line with the name of the app. Weird coincidence. It’s back to grey now that I’ve unticked the translucent feature.