Mobile Menu Dissappeared

Hi – I noticed the mobile menu has disappeared from the site.

Here is the custom CSS I have so far:

.avia-post-nav {
visibility: hidden;
}

.main_color b, .main_color strong 
 {
  color:#000000 !important;
}

.main_color a, .main_color .widget_first, .main_color strong a, .main_color #js_sort_items a:hover, .main_color #js_sort_items a.active_sort, .main_color .special_amp, .main_color .taglist a.activeFilter {
  color:#719430;
}

.phone-info span {
font-size: 12px;
}

#top #header_meta li {
    border: none;
}

.avia-caption av-slideshow-caption{
top: -50px;
}

@media only screen and (max-width: 1000px) {
nav.main_menu {display:none !important;}
#advanced_menu_toggle, #advanced_menu_hide {display:block !important;}
}

div#header_main_alternate {
background-color: #033367;
}

.main_menu ul:first-child > li > a {color: white!important;
}

#advanced_menu_toggle, #advanced_menu_hide {
    background-color: #033367!important;
}

.no-hover
{ a:hover 
    background: transparent;
    cursor: default;
}

@media (min-width: 800px)
 {
.fblogo img{
 position: relative;
  top: 50%;
  transform: translateY(-50%);
}}