Dark background for a label

[zanac]

Hi,

how can i make a "white rectangular" for fill a label, and of course use a black font inside to see the room name much more visible? In the screenshot the name "Corridoio" don't appare...

[PiotrMachowski]

It should be possible to do using card mod

[zanac]

Ok have you Got a sample? Which CSS Class i should overwrite?