m4lab-mobile.css

body.offcanvas-active {
  overflow: hidden;
}

.offcanvas-header {
  display: none;
}

@media (max-width: 768px) {
  .offcanvas-header {
    display: block;
  }

  .navbar-collapse {
    position: fixed;
    top: 0;
    bottom: 0;
    left: 100%;
    width: 100%;
    padding-right: 1rem;
    padding-left: 1rem;
    overflow-y: auto;
    visibility: hidden;
    background-color: white;
    transition: visibility .2s ease-in-out, transform .2s ease-in-out;
  }

  .navbar-collapse.show {
    z-index: 1;
    visibility: visible;
    transform: translateX(-100%);
  }
}