Changing color of Select


I have a requirement in my project wherein I have to highlight invalid data in Select.
The data which was previously selected by user, may become invalid in future and when it is accessed for update, it must be marked as invalid.
For this, I tried by applying a style which sets the Select background color to red.
But this did not seem to affect its color.

I have to either change the Select’s color to red or change the color of particular item to red.

Can you please tell me how I can go about this?

Thanks in advance.