Conditionnal formatting: how to account for ""

Hello,

I am trying to apply a basic conditionnal formatting on an =IF(A1="","",A1) type formula.
I got 3 rules:
-If the answer is 0, I want it green;
-If the answer is different than 0, I want it red;
-If the answer is "", I want no format.

For some reason, excel considers "" as > than 0 and so colors the cell in red. Anyone knows how to solve it?

Thanks