Making Drop Down Menus dissapear on Mobile…

I cant find the CSS to make my drop down menu’s go away on Mobile phones.

https://www.Bangorchildcare.com

The drop downs are contained in a

with the class .sub-menu

So, In my external CSS i set

@media screen and (max-width: 768px) {
ul.sub-menu{display:none !important;}
}

But it does not work. Interesting thing is when I Inspect in Chrome…. I see that u.submenu(display:none !important;) is STRIKETHROUGH

What CSS am I missing to access those Sub Menu’s and make them disappear on Mobile?