iPhones with notch white space

I’m running into an issue on the iPhone X and other iOS devices with a notch.

I can’t get rid of the white space around the notch in landscape mode.

I’ve tried to add viewport-fit=cover to the head of the page as for example:

<meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover">

As for example https://modelessdesign.com/backdrop/283 suggests, but it seems to be totally ignored by the unbounce page.

Does anybody have any suggestions on how to get rid of the white space around the notch?

Thanks!