It appears the user is stating that on iPad when the left TOC column is collapsed, the horizontal readable article margins are actually smaller than when the TOC column is expanded.

https://ticket.wikimedia.org/otrs/index.pl?Action=AgentTicketZoom;TicketID=11959673

On the 2021 iPad Pro 11”, when the navigation menu on the side is minimized in landscape
mode, the width of the text area actually shrinks. Here are overlapping screenshots
showing the text column becoming narrower when the nav menu isn’t shown:

The actual dimensions of the text areas shown here are approx 1306x389 when the navigation
menu is hidden, and 1506x343 when the nav menu is shown. This definitely seems backwards.
It would be preferable for the text width to become wider when the nav menu is hidden and
the text is centered.

Additionally, it would also make sense for tables to use the maximum width of the screen
whenever the navigation menu is collapsed.

To add to this, I realized after I sent this that the single-column text seems to be set to a fix width in both portrait and landscape, and in both cases, the text is set to 2/3 when the ToC column is displayed.

I think a better layout would be that in landscape mode, the body text should take up 3/5 or 2/3 of the screen no matter what!