datepicker-navigation-select.scss

ngb-datepicker-navigation-select > .custom-select {
  flex: 1 1 auto;
  padding: 0 0.5rem;
  font-size: 0.875rem;
  height: 1.85rem;

  &:focus {
    z-index: 1;
  }

  // IE11, Edge: Fix arrow icon disappears on focus
  &::-ms-value {
    background-color: transparent !important;
  }
}