How can you create a text formula field to look at a date field and color the font and background

I have two date fields, one is Delivery Date and the other is Delayed Delivery. I also have a text formula field that I want to color the background on. The text formula field would simply look at a date entered in the Delayed Delivery date field and color the background yellow and the font red.

This is what I have but it is not picking up anything.

If(
[Delayed Delivery]<>[Delivery Date],"<div style=\"background-color:yellow;\"><b><font color = red>")