Change X theme's Main Navigation Breakpoint

x-menu.css

@media (min-width: 1080px) {

    .x-nav-wrap.desktop {
        display: none
    }
  
    .x-nav-wrap.mobile {
        display: block
    }
  
    .x-nav-wrap.mobile.x-collapsed {
        display: none;
    }
  
    .masthead-inline .x-btn-navbar {
        display: block;
        float: right
    }
  
    .masthead-stacked .x-btn-navbar {
        display: inline-block
    }
  
    .x-navbar-fixed-top-active .x-navbar-wrap {
        height: auto
    }

}