Modify the background color of a perspective column container

Hello all
I am trying to modify the background color with a bit. I have already made the style for the background but i dont see any place in the root to put the bit.
Should i create the root variable? Should i make other view and use a rectangle or something like that?

If i click “Ok”
The style gets like this…

Your expression is a direct equality comparison. Assuming you want a style named “Alarmbackground” to be applied when the tag in your screenshot has a value of 2, then you want an expression like this:

if ({[default]TagPath/tagName.value} = 2, "alarmBackground", "")

In this expression, if the alarm has a value of 2, then “Alarmbackground” is supplied by the expression, else an empty string is applied.