There were two useful attributes for datascroller in 3.3: selectedStyleClass and inactiveStyleClass.
However I don't see them in 4.2 version:
However the migration giude states that component hasn't changed
So how can achieve the same functionality in 4.2 ?
I found in the documentation that facets can be defined for the dataScroller.
However it seems that they are attached to buttons. I have no clue how to use it for the page numbers.
The only visible solution is to redefine a.rf-ds-act styles.