Apply multiple field styles

I am trying to apply two field styles on the incident Number field.Below are the 2 field styles:

1.If state is In Progress , field style used is "text-align:right"

2.If Priority is P1 , field style used is "background-image: url('myIcon.gif');"

So when an Incident State is In Progress & Priority is P1 ,only the "text-align:right" is getting applied.But I want both the styles to get applied.

Kindly help.