Excel – (Excel) Conditional Formatting based on Adjacent Cell Value

I think this is what you're looking for:

=AND(COUNTBLANK($D1)=0,$D1=0)

Note that when you apply it to the whole column, each cell will only look at its respective row. You'll want to keep the reference of $D1 instead of using $D:$D

I haven't been able to find a way to make this work using default Excel conditional formatting. It is possible to create your own conditional formatting algorithm in VBA that will enable this functionality, however:

Sub UpdateConditionalFormatting(rng As Range)
    Dim cell As Range
    Dim colorValue As Integer
    Dim min, max As Integer

    min = WorksheetFunction.min(rng)
    max = WorksheetFunction.max(rng)

    For Each cell In rng.Cells
        If (cell.Value > 0) Then
            colorValue = (cell.Value / max) * 255
            cell.Interior.Color = RGB(255 - colorValue, 255, 255 - colorValue)
        ElseIf (cell.Value < 0) Then
            colorValue = (cell.Value / min) * 255
            cell.Interior.Color = RGB(255, 255 - colorValue, 255 - colorValue)
        End If

        Next cell
    End
End Sub

The code above will generate the following color scheme, and can be easily modified to fit whatever palette you have in mind:

You can use this code in a macro, or drop it into a Worksheet_Change event and have it updated automatically (note that when installed in the Worksheet_Change event handler you will lose undo functionality):

Sub Worksheet_Change(ByVal Target As Range)
    UpdateConditionalFormatting Range("A1:A21")
End Sub