First issue :
you X has the cursor : pointer
, and works fine , it is just overlayed by a div of class <div class="bt-overlay"></div>
so the fix will be :
.bt-menu-trigger {
position: fixed;
top: 15px;
right: 20px;
display: block;
width: 50px;
height: 50px;
cursor: pointer;
z-index:99;
}
Second issue:
Visibility is not a standard , use opacity instead , and it will work fine
here is the fix:
.bt-menu ul li {
padding: 16px 0;
opacity: 0;
visibility: hidden;
-webkit-transition: background-color 0.3s ease-in-out, opacity 2s ease-in-out;
-moz-transition: background-color 0.3s ease-in-out, opacity 2s ease-in-out;
-ms-transition: background-color 0.3s ease-in-out, opacity 2s ease-in-out;
-o-transition: background-color 0.3s ease-in-out, opacity 2s ease-in-out;
transition: background-color 0.3s ease-in-out, opacity 2s ease-in-out;
}