Conditional Formatting for a text field ValueExpression for durations

Hi all, 

I am attempting to do some SLA comparison reporting and I am able to do the value expression below but am having trouble applying conditional formatting. GTE 0 then make it green text with green background. LT 0 then make it red text with red background. I have tried taking a standard mode code set and applying it to the text mode but something is not going right. 

descriptionkey=duration
displayname=Actual Duration Variance (Days)
textmode=true
valueexpression=ROUND((((SUB({actualDuration},{duration}))/60)/8),1)
valueformat=HTML

Thanks for the advice!

Matt