Logic on Form Changes drop-down width

Hi is there a fix on this or can someone elaborate on the temp-fix? Having the same issue. Logic on the Form Changes drop-down width; if you’ve enabled the enhanced user option. New to WP and CSS. I see others have had this issue but those threads are now closed.

@jwake7 advised the command below solved his width issue, but I am unsure where should I input the command? Tried to input into the “Custom CSS Class” field in the Appearance Tab of the List Field… but the results were the same.

ANY help would be awesome!!!

.ginput_list .chosen-container {min-width:200px !important;}