Force "fixed div" to fill all space on smartphones?

Hi there,

I was wondering if there was a technique, to force a fixed full screen div to fill all the space on smartphone, even when the user scrolls down and the little android info bar disappears.

I made a small live video recording here to showcase my problem.
At the moment, when we click on the mobile menu hamburger, the menu appears, which looks cool but if we scroll a little (for some reason), then the android menu bar disappear leaving an empty space which is filled again my the fixed div a second after we stop scrolling… which looks a bit cheap :slight_smile:

Is there a way for the fixed div to fill all the space at all time ?
Thank you !

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