Hello Vicki,
I checked your site on an iPad in portrait view and it seems to show fine.
Perhaps the breakpoint where the sidebar hides is in-between device sizes, which would be very uncommon user scenario so I wouldn’t worry about it too much.
If you wan’t to fine tune it you can use this CSS breakpoint
@media (min-width: 992px) and (max-width: 1199px) {
//add your css here
}
regards
Imre