Change font size on [woo_multi_currency_plain_horizontal]

Hi there

Is there any chance that I can change the font size on the widget [woo_multi_currency_plain_horizontal]. I am already using the following custom CSS, but it’s not working:

.woo-multi-currency .wmc-currency{font-family: Arial !important; font-size: 9px !important;}
.woo-multi-currency .wmc-currency a{color:white !important;}

Any idea on how to solve this?

Any help is much appreciated.

Best regards,
Victor