How to reduce the vertical spacing b/w the mobile menu and mobile top bar in York template?

When the hamburger menu is open, I'm trying to reduce the vertical spacing of the mobile menu to the top bar. Tried a bunch of code, none of them worked. Looks like the mobile menu is centered vertically and its position moves up and down based on the browser window height. Very frustrating. I just want it to stay higher up on the screen and not too far down from the mobile top bar. Any help would be much appreciated.My site is http://circle-cobalt-nc4z.squarespace.com

@Jenqwang Add to Home > Design > Custom CSS

div#overlayNav {
   min-height: unset !important;
   bottom: unset !important;
}

OMG! Thank you so much @tuanphan! You are a life saver!!!!!

@Jenqwang You're welcome. Click Accept Answer, other members can use if they know it worked. I think York has many users.

--I'm writing about 2000+ Custom CSS for all templates in Squarespace. York will have this week, if you are interested, let me know, I will send it when completed ;)

I tweaked the code a bit to add a fixed top margin:div#overlayNav {

min-height: unset !important;

top: 50px !important;

bottom: unset !important;

}

And there's the before & after comparison. Hope this could help someone else. You guys rock!! ^-*