Example:
D3 is "3/31/2015 7:30:00 PM"
D4 is "4/1/2015 12:00:00 AM"

I would like D4 to be automatically formatted (red text) because it occurs longer than 3 hours after D3. Is this possible?

Slightly different, D5 is "=NOW()", would the formatting for the above also work on the date that D5 gives (will be 48 hours).

Thank you very much,
Micheal