fix: too much toggleMainMenu buttons

src/views/partials/header.pug

@@ -65,8 +65,6 @@ div
               li
                 button.segment.padding-small.text-hover.text-semibold.text-color-heading(role='log out' onclick="document.querySelector('sib-auth').logout();" data-trans='header.logOut')
 
-        button.segment.lg-hidden.icon-menu#toggleMainMenu
-
       //- User menu visible on small screens
       details.user-menu.segment.lg-hidden.user-controls
         summary
@@ -118,6 +116,4 @@ div
               li
                 button.segment.padding-small.sm-padding-medium.sm-padding-left-xlarge.text-hover.text-bold.text-color-heading(role='log out' onclick="document.querySelector('sib-auth').logout();" data-trans='header.logOut')
 
-      button.segment.lg-hidden.icon-menu#toggleMainMenu
-