Widget overflow hidden, should overlay

Hello

my name is Angie and I love Sela!

I’m very grateful to this forum as I got my site going by trial and error after reading here.

I did implement a booking widget in my first front page area on my static front page. This text widget contains a drop down with a check-in and check-out calendar. The check-out calendar doesn’t overlay at it’s bottom.
I believed this was the reason:

.widget-area {
	overflow: hidden;
}

So I answered with this in my Sela child themes css:

.widget-area {
	overflow: visible !important;
}

and this

div#widget-area-5 {
    overflow: visible;
}

But this is not quite it I’m afraid. Could you please point me in the right direction here to make the check-out calendar visible please.

Thank you very much in advance from New Zealand

The site I need help with is thebeachhouse-nelson.com.