FED Cohort assignments

@talbs Would you mind reviewing this?
I'm assuming these rules are to counter the ones called in by the ``%text-sr`` extend above. This seems more messy than needed. I'd recommend either going the way of ``display: block/none;`` for these two states or creating an extend alongside the ``%text-sr`` one that can counter it and be referenced from anywhere we need it. Also, watch out for any CSS transitions on elements - all of these properties would apply them. :/