Conditional Change of Font Size

Using traditional Conditional Formatting will not allow you to change font size. I want to set a series of cells to lower their font size to Arial 9 if the value is between 100 and 999, and to Arial 7 if the value is greater than 999.

Arial is the default font face, so that isn't changing at all.

This will set the font size of cells in the range A1:C5 on sheet1:

Sub SetFontSize()
    Dim rngCell As Range
    
    For Each rngCell In Worksheets("Sheet1").Range("A1:C5").Cells
        If rngCell.Value >= 100 And rngCell.Value <= 999 Then
            rngCell.Font.Size = 9
        ElseIf rngCell.Value > 999 Then
            rngCell.Font.Size = 7
        End If
    Next rngCell

End Sub