@apt_mmenu_hamburger_bar_background_color: #999;

.apt_mmenu_hamburger {
   cursor: pointer;
   display: block;
   position: relative;
   width: 30px;
   height: 15px;
   overflow: hidden;
   box-sizing: border-box;
}
.apt_mmenu_hamburger {
   display: block;
   position: relative;
   width: 30px;
   height: 15px;
   float: left;
   overflow: hidden;
   box-sizing: border-box;
}
.apt_mmenu_hamburger span {
   background-color: @apt_mmenu_hamburger_bar_background_color;
   display: block;
   position: absolute;
   height: 2px;
   width: 100%;
   transition: none 0.5s ease;
   transition-property: transform, top, left, opacity;
}
.apt_mmenu_hamburger span.top-bar {
   top: 0px;
}
.apt_mmenu_hamburger span.middle-bar {
   top: calc(50% - 1px);
}
.apt_mmenu_hamburger span.bottom-bar {
   bottom: 0px;
}
html.mm-opened & .apt_mmenu_hamburger span.top-bar {
   transform: rotate( 45deg );
   top: 7px;
}
html.mm-opened & .apt_mmenu_hamburger span.middle-bar {
   opacity: 0;
}
html.mm-opened & .apt_mmenu_hamburger span.bottom-bar {
   transform: rotate( -45deg );
   top: 7px;
}