css：

...
#menu-like-mt.opened span {background: #F5513A;position:relative;}
#menu-like-mt.opened span:nth-child(1) {-webkit-transform: rotate(45deg);top:6px;}
#menu-like-mt.opened span:nth-child(2) {opacity:0;}
#menu-like-mt.opened span:nth-child(3) {-webkit-transform: rotate(-45deg);bottom:6px;}
...