Backdrop | viewport-fit=cover is confusing for app developers
(Updated on Dec 8, 2017) First, you know the Safari on iPhone X automatically applies paddings. The contents will be restricted inside the safe area by default. From web developer's perspective, as Apple/ WebKit team mentions, you can exclude the auto-applied paddings to use the whole screen on iPhone X by declaring viewport-fit=cover within viewport meta element in the HTML.
