Color Code a Date Range

I need a code that color codes a range of dates. For example:

+15 days through + 30 days should be yellow

+2 days through + 14 days should be orange

+ 1 day though overdue should be red

This is what I have to start with, but I don't know where to go from here: 

If([Approved End Date]=(Today()+Days(30)),"<div style=\"background-color:yellow;\">"&[Approved End Date]&"</div>",
ToText([Approved End Date]))

Any help would be greatly appreciated. 

Thank you!