Increase window border

A Former User

Hello.

I've just upgraded to Windows 10, and I'm using the built-in feature in Windows 10 whereby the focused window's window bar is an accent colour (and unfocused window have a grey window bar).

Opera only has a 1-pixel border that changes colour (no window bar). I seem to recall that it is possible to increase the window border to something more visible (e.g. 5 pixels or 10 pixels). Can anyone please remind me how to do that?

Alternatively, if there is now a way to force Opera to have a window bar again (like most other programs on my computer), I'd be happy to hear about it.

Thanks
Samuel