Fix LESS error

src/less/main.less

@@ -298,6 +298,8 @@ html {
 .hamburger {
   background: transparent;
   display: block;
+  border: none;
+  outline: none;
   height: 32px;
   position: absolute;
   top: 8px;

templates/index.html.twig

@@ -136,7 +136,7 @@
                 </div>#}
             </nav>
             <div id="page-content-wrapper">
-                <div class="burger-wrapper">
+                <div class="hamburger-wrapper">
                     <button type="button" class="hamburger is-closed animated fadeInLeft" data-toggle="offcanvas">
                         <span class="hamb-top"></span>
                         <span class="hamb-middle"></span>