Is it possible to have a cell background color change when a particular
condition is met?

In this case, specifically a DATE.

When an item is entered in a row, one of the entries is the current date.
Then when the item is complete, a "completed by" date is also entered in a
different cell and yet another cell displays the amount of days an item took
to get completed.

Is it possible that that 1st cell with the entered date can turn red when 3
days have gone by and nothing has been entered in the c"completed by" cell?



Thanks for reading!