Height 100vh is too tall on iOS Safari

On iOS Safari, if the two navigation bars are shown, 100vh is actually taller than the screen area available. So if you make a scrollable popup, it won't be possible to scroll down far enough to see all of the content.

In my site, just setting .basicLightbox's height to 100% instead seems to fix it.

Locate the .basicLightbox styles and reproduce a scrollable popup on iOS Safari with both navigation bars visible. Verify whether changing the height behavior resolves the viewport overflow, then confirm that all popup content can be reached by scrolling on the affected browser.

Written by the indexing model from the issue text.