chamilo-lms2/app/Resources/public/assets/bootstrap/less/mixins/responsive-visibility.less

// Responsive utilities

//
// More easily include all the states for responsive-utilities.less.
.responsive-visibility() {
  display: block !important;
  table&  { display: table !important; }
  tr&     { display: table-row !important; }
  th&,
  td&     { display: table-cell !important; }
}

.responsive-invisibility() {
  display: none !important;
}