Saddly, I am using multi-select with search, which does not have those classes. It does not have specificity at the hierarchical levels. They look to apply to the dropdown option. I am using multi-select to similar to the other filters.
An unrelated item is, I was unable to use the dropdown option as I found it was not possible to clear the first selected value. After selecting an initial value from the dropdown, then changing it to a second value, it is not possible to clear the first value. Clicking the filter reset button, clears the second value, but replaces it with the first value. Even refreshing the screen does not clear it. You have to close the tab to remove the value. Or change the field display type to multi-select and manually deselect it.