.navbar-toggle {
  overflow: hidden;
}
.navbar-toggle .icon-bar {
  transition: opacity, transform;
  transition-duration: 200ms;
  transition-timing-function: cubic-bezier(0.7, 0, 0, 0.7);
}
.navbar-toggle:not(.collapsed) .icon-bar:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}
.navbar-toggle:not(.collapsed) .icon-bar:nth-child(2) {
  opacity: 0;
  /* transform: translateX(-100%); */
}
.navbar-toggle:not(.collapsed) .icon-bar:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}