<div id="menu-toggle">
  <div id="hamburger">
    <span></span>
    <span></span>
    <span></span>
  </div>
  <div id="cross">
    <span></span>
    <span></span>
  </div>
</div>
* {
  transition:.25s ease-in-out;
  box-sizing:border-box;
}

body {
  background:#d9e4ea;
}

span {
  display:block;
  background:#566973;
  border-radius:2px;
}

#menu-toggle {
  width:100px;
  height:100px;
  margin:50px auto;
  position:relative;
  position:relative;
  cursor:pointer;
  background:rgba(255,255,255,.4);
  border-radius:5px;
  &:hover {
    background:rgba(255,255,255,.8);
  }
  #hamburger {
    position:absolute;
    height:100%;
    width:100%;
    span {
      width:60px;
      height:4px;
      position:relative;
      top:24px;
      left:20px;
      margin:10px 0;
      &:nth-child(1){
        transition-delay:.5s;
      }
      &:nth-child(2){
        transition-delay:.625s;
      }
      &:nth-child(3){
        transition-delay:.75s;
      }
    }
  }
  #cross {
    position:absolute;
    height:100%;
    width:100%;
    transform:rotate(45deg);
    span{
      &:nth-child(1){
        height:0%;
        width:4px;
        position:absolute;
        top:10%;
        left:48px;
        transition-delay:0s;
      }
      &:nth-child(2){
        width:0%;
        height:4px;
        position:absolute;
        left:10%;
        top:48px;
        transition-delay:.25s;
      }
    }
  }
}

#menu-toggle.open {
  #hamburger {
    span {
      width:0%;
      &:nth-child(1){
        transition-delay:0s;
      }
      &:nth-child(2){
        transition-delay:.125s;
      }
      &:nth-child(3){
        transition-delay:.25s;
      }
    }
  }
  #cross {
    span {
      &:nth-child(1){
        height:80%;
        transition-delay:.625s;
      }
    }
    span {
      &:nth-child(2){
        width:80%;
        transition-delay:.375s;
      }
    }    
  }
}
$('#menu-toggle').click(function(){
  $(this).toggleClass('open');
})

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js