unity/resources/sass/user/applications/_responsive.scss

// Responsive Applications

@include media-breakpoint-down(md) {
  .app-inner-layout__sidebar {
    display: none !important;
  }

  .mobile-app-menu-btn {
    display: block;
  }

  .open-mobile-menu {

    .app-inner-layout__sidebar {
      display: block !important;
    }
  }
}