How to default to a blank/grey cell colour if other conditional formatting rules aren't met

Question

I have a spreadsheet working (fairly) well doing traffic light (red,yellow,green) colour fill, using a set of conditional formatting rules. However, I'd like cells in the same range without any value entered, to default to a grey. I've tried the basic Apply to Range formatting selecting the drop down Is Empty. I've also tried using the isblank condition, as shown. How to I get cells to default to grey, if not in my other conditions?

Answer 1

you need to assign a range to the conditional formatting:

=isblank(B2:B)

also bear in mind that the conditional formatting is sequential, which means that is if a rule is above and is conditioning the same values, then the rule below will not be applied.

You can drag the grey above to have the empty values turn gray by dragging the 3 dots in the image below