bartik.css in Responsive Tables 7.2

/**
 * Responsive tables.
 */
@media screen and (max-width:28.125em) { /* 450px */
  th.priority-low,
  td.priority-low,
  th.priority-medium,
  td.priority-medium {
    display: none;
  }
}
@media screen and (max-width:45em) { /* 720px */
  th.priority-low,
  td.priority-low {
    display: none;
  }
}