I would like to have the result of my function to change the color of the
cell in which the result is displayed.

For example:

1- if the value of cell A1 is less than or equal to the value of cell C2
then display the difference between cells C2 and A1 in cell D4 with a "green"
background.

or

2- if the value of cell A1 is greater than the value of cell C2 then display
the difference between cells C2 and A1 in cell D4 with a "red" background.

I can get the "IF" function to display the numeric value I want, but cannot
get the background shading to change with the perameters I specified above.

Any help would be appreciated.