<section class="wrapper">

  <section class="material-design-hamburger">
    <button class="material-design-hamburger__icon">
      <span class="material-design-hamburger__layer"></span>
    </button>
  </section>

  <section class="menu menu--off">
    <div>Android's Material Design Hamburger Animation</div>
    <div>Adapted for the web by <a href="https://swirlycheetah.com" target="_blank">Chris Wheatley</a></div>
    <div><a href="https://github.com/swirlycheetah/material-design-hamburger" target="_blank">Available on GitHub</a></div>
    <div><a href="https://twitter.com/swirlycheetah" target="_blank">Follow me on Twitter @swirlycheetah</a></div>
  </section>
  
</section>

@import url(https://fonts.googleapis.com/css?family=Roboto);

body {
  background: #009688;
}

.wrapper {
  height: 100%;
  transition: all 300ms ease-in-out;  
  margin: 1em 0;
  padding: 0;
}

.background--blur {
  background: #004d40;
}

.menu {
  font-size:2em;
  font-family: 'Roboto', sans-serif;
  color: #333;
}

.menu div {
  margin: 1em;
  padding-bottom: 1em;
  border-bottom: 1px solid #ccc;
}

.menu a {
  text-decoration: none;
  color: #3367d6;
}

.menu a:hover {
  text-decoration: underline;
}

.menu div:last-child {
  border: 0;
}

.menu--off {
  position: absolute;
  left: -50%;
  width: 50%;
  display: block;
  background: #eee;
  min-height: 600px;
  height: 125%;
  margin-top: 1em;
  transition: all 300ms;
}

.menu--on {
  left: 0;
  box-shadow: 8px 8px 20px 0 rgba(0, 0, 0, 0.2);
  transition: all 300ms;
}

.material-design-hamburger button {
  display: block;
  border: none;
  background: none;
  outline: 0;
}

.material-design-hamburger__icon {
  padding: 3rem 1rem;
  cursor: pointer;
}

.material-design-hamburger__layer {
  display: block;
  width: 100px;
  height: 10px;
  background: #eee;
  position: relative;
  animation-duration: 300ms;
  animation-timing-function: ease-in-out;
}

.material-design-hamburger__layer:before, .material-design-hamburger__layer:after {
  display: block;
  width: inherit;
  height: 10px;
  position: absolute;
  background: inherit;
  left: 0;
  content: '';
  animation-duration: 300ms;
  animation-timing-function: ease-in-out;
}

.material-design-hamburger__layer:before {
  bottom: 200%;
}

.material-design-hamburger__layer:after {
  top: 200%;
}

.material-design-hamburger__icon--to-arrow {
  animation-name: material-design-hamburger__icon--slide;
  animation-fill-mode: forwards;
}

.material-design-hamburger__icon--to-arrow:before {
  animation-name: material-design-hamburger__icon--slide-before;
  animation-fill-mode: forwards;
}

.material-design-hamburger__icon--to-arrow:after {
  animation-name: material-design-hamburger__icon--slide-after;
  animation-fill-mode: forwards;
}

.material-design-hamburger__icon--from-arrow {
  animation-name: material-design-hamburger__icon--slide-from;
}

.material-design-hamburger__icon--from-arrow:before {
  animation-name: material-design-hamburger__icon--slide-before-from;
}

.material-design-hamburger__icon--from-arrow:after {
  animation-name: material-design-hamburger__icon--slide-after-from;
}

@keyframes material-design-hamburger__icon--slide {
  0% {
  }
  100% {
    transform: rotate(180deg);
  }
}

@keyframes material-design-hamburger__icon--slide-before {
  0% {
  }
  100% {
    transform: rotate(45deg);
    margin: 3% 37%;
    width: 75%;
  }
}

@keyframes material-design-hamburger__icon--slide-after {
  0% {
  }
  100% {
    transform: rotate(-45deg);
    margin: 3% 37%;
    width: 75%;
  }
}

@keyframes material-design-hamburger__icon--slide-from {
  0% {
    transform: rotate(-180deg);
  }
  100% {
  }
}

@keyframes material-design-hamburger__icon--slide-before-from {
  0% {
    transform: rotate(45deg);
    margin: 3% 37%;
    width: 75%;
  }
  100% {
  }
}

@keyframes material-design-hamburger__icon--slide-after-from {
  0% {
    transform: rotate(-45deg);
    margin: 3% 37%;
    width: 75%;
  }
  100% {
  }
}

(function() {

  'use strict';

  document.querySelector('.material-design-hamburger__icon').addEventListener(
    'click',
    function() {      
      var child;
      
      document.body.classList.toggle('background--blur');
      this.parentNode.nextElementSibling.classList.toggle('menu--on');

      child = this.childNodes[1].classList;

      if (child.contains('material-design-hamburger__icon--to-arrow')) {
        child.remove('material-design-hamburger__icon--to-arrow');
        child.add('material-design-hamburger__icon--from-arrow');
      } else {
        child.remove('material-design-hamburger__icon--from-arrow');
        child.add('material-design-hamburger__icon--to-arrow');
      }

    });

})();