th.sortable {
  cursor: pointer;
  position: relative;
}

th.sortable:after {
  content: "▴";
  position: absolute;
  right: 8px;
  opacity: 0.3;
}

th.sortable.sort-asc:after {
  content: "▴";
  opacity: 1;
}

th.sortable.sort-desc:after {
  content: "▾";
  opacity: 1;
}