Please help, I am doing a report and need a formula that color codes cells

I have top row that had each month for 2 years that is month with last day of month ie. 3/31/16, 4/30/16, 5/31/16.....

the first column has "days" each one being different, but top working down, 156,147,139,125,105,85... (based on how long task take to complete)

I would like the interesting cell to have top row date minus the amount of days,

3/31/16 - 147 days = 11/5/15 if this date is in the future of TODAY +14 days then would be green if it is between today and 14 days would be yellow, if it is today and passed then would be red.

Today meaning every time I open it today would be reflected as current day



please help. thank you in advance