Event when font color changed

Dear all

Could anyone help me change this vba worksheet_selection_change event to when font color in range("A1:A12") is changed.
the code is here

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
    Dim a As Range, q As Variant
    Set a = Range("a1:a11")
    Range("a13") = ""
    For Each q In a.Cells
        If q.Font.Color = RGB(255, 0, 0) Then
            Range("a13") = Range("a13") + q
        End If
    Next q
End Sub

Thanks