Help decreasing bottom margin/padding for Gallery Grid on mobile?

Hi -

If anyone could help -- much appreciated. Password "mosaic"

The spacing looks fine within the Squarespace editor but when I open it on my phone (which is a small iphone 12 mini) there is a bunch of extra space below the Gallery Grid which I can't get rid of.

This is on the homepage but the issue repeats itself wherever I use the Gallery Grid.

I am attaching the difference in appearance in screenshots. The one with the extra space is the live view on my phone and the one without is how it looks in the editing and preview modes in Squarespace. 

I have tried this CSS which decreases/adds space in the Squarespace view but does not move it at all on my mobile/live view:

/* Reduce space under grid - mobile */
@media screen and (max-width:400px) {
.sqs-gallery-block-grid {
    margin-bottom: -250px !important;
}
}

Thank you for any assistance!

Hi,

What is page url?

Hi Tuan -- it is: https://dolphin-parsnip-f4ma.squarespace.com/ (password: mosaic).

Thank you!

Thank you @tuanphan!!