Alterar a cor do ítem selecionado do tradiogroup

procedure TForm1.RadioGroup1Click(Sender: TObject);
var
i : Integer;
begin
for i := 0 to RadioGroup1.Items.Count-1 do begin
TRadioButton(RadioGroup1.Controls[i]).Font.Color := clBlack;
TRadioButton(RadioGroup1.Controls[i]).Font.Style := [];
end;
TRadioButton(RadioGroup1.Controls [RadioGroup1.ItemIndex]).Font.Color := clRed;
TRadioButton(RadioGroup1.Controls [RadioGroup1.ItemIndex]).Font.Style := [fsBold];
end;