.rb-menu-button {

  position: relative;

}

.rb-menu-button:after {

	content: '';
	display: block;
	width: 60%;
	height: 0px;
	position: absolute;
	bottom: -10px;
	left: 50%;
	transform: translateX(-50%);
	z-index: -1;
  transition: 300ms;

}

.rb-menu-button:hover:after,
.current-menu-item .rb-menu-button:after {

  height: 5px;

}

.sub-menu .rb-menu-button:after {

  display: none;

}