Burger menu and menu responsiveness not working anymore

I made some (what I thought were) innocent changes this website https://www.gcahomeinspections.com and now I’m having issues with the menu. The menu items are now overlapping the logo and the burger menu is no longer working. I didn’t keep a log of everything I did but all I remember doing is making some small changes to the menu font and background colors. I’ve tried reverting these changes in case it did cause the issue but nothing has changed. I used Chrome’s Inspect Console tool and it says jQuery is not defined.

avia.js?ver=4.5.4:1842 Uncaught ReferenceError: jQuery is not defined
at avia.js?ver=4.5.4:1842

I deactivated and reactivated as many plugins as I could to see if I might be a conflict. The ones I didn’t test are network activated and I’m not having the same issue on any other sites on the network. From what I can tell it’s not a plugin conflict.

I checked my Performance settings and all merging and compression is disabled, “Always load all elements” and “Always load media features” are selected. All boxes are unchecked.

My current Enfold Theme Version Number is 4.5.4. I’m on WordPress 5.1.1.

This is what I have under Quick CSS:

@media only screen
and (min-device-width: 768px)
and (max-device-width: 1024px)
and (-webkit-min-device-pixel-ratio: 1) {

.slideshow_inner_caption{
width: 445px;
}

}

.avia-menu-text {
text-transform: uppercase}

.av-catalogue-price {
color: #02254F;
font-weight: bold;}

@media (max-width: 1200px) {
.av-catalogue-price {
position: relative!important;
}
}

.avia-section.background-img-responsive {
background-size: cover !important;
}

What could be causing these issues?