Hi,
I checked and can see there are syntax error in your css codes.

Your @media is not properly closed.
Please change the code that reads
@media (max-width:1200px) {
.x-nav-wrap.desktop {
display: none;
}
.x-btn-navbar {
display: block;
float: right;
}
@media (max-width:1200px),
all .x-nav-wrap.mobile.x-collapsed {
display: none;
}
@media (max-width:1200px),
all .x-nav-wrap.mobile {
display: block;
}
@media (max-width:1200px),
all .x-nav-wrap.mobile.x-collapsing,
.x-nav-wrap.mobile:not(.x-collapsed) {
display: block;
}
to this
@media (max-width:1200px) {
.x-nav-wrap.desktop {
display: none;
}
.x-btn-navbar {
display: block;
float: right;
}
.x-nav-wrap.mobile.x-collapsed {
display: none;
}
.x-nav-wrap.mobile {
display: block;
}
.x-nav-wrap.mobile.x-collapsing,
.x-nav-wrap.mobile:not(.x-collapsed) {
display: block;
}
}
Hope that helps