fleet/frontend/pages/ManageControlsPage/OSUpdates/components/OSVersionTable/_styles.scss

.os-version-table {
  .hosts-cell__wrapper {
    display: flex;
    align-items: center;
    justify-content: space-between;
  }

  .os-hosts-link {
    opacity: 0;
    transition: 250ms;
  }

  tr:hover {
    .os-hosts-link {
      opacity: 1;
    }
  }

  .data-table-block th:nth-last-child(2) {
    border-right: none;
  }
}