<link rel="stylesheet" href="style.css">
  <nav class="menu-opener">
    <div class="menu-opener-inner"></div>
  </nav>
  <nav class="menu">
    <ul class="menu-inner">
      <a href="#" class="menu-link">
        <li>Accueil</li>
      </a>
      <a href="#" class="menu-link">
        <li>Portfolio</li>
      </a>
      <a href="#" class="menu-link">
        <li>Themes</li>
      </a>
      <a href="#" class="menu-link">
        <li>Templates</li>
      </a>
      <a href="#" class="menu-link">
        <li>Contact</li>
      </a>
    </ul>
  </nav>
  <script type="text/javascript" src="https://code.jquery.com/jquery-1.9.1.js"></script>
  <script src="menu-opener.js"></script>

@import url(https://fonts.googleapis.com/css?family=Open+Sans:100,300,400,700);
*,
*::before,
*::after {
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  box-sizing: border-box;
}

body {
  background: url("http://www.philippefercha.com/cd/toggle-menu-bg.jpg") no-repeat;
  background-size: 2000px;
  font-family: 'Open Sans', Helvetica, Arial, sans-serif;
}

a {
  display: block;
  width: 100%;
  height: 100%;
}

.menu-opener, .menu-opener:hover, .menu-opener.active, .menu-opener-inner, .menu-opener-inner::before, .menu-opener-inner::after, .menu, .menu.active {
  -webkit-transition: 250ms all;
  transition: 250ms all;
}

.menu-opener {
  cursor: pointer;
  height: 64px;
  position: absolute;
  top: 2%;
  left: 1%;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  width: 64px;
}
.menu-opener:hover, .menu-opener.active {
  background: #f1c40f;
}

.menu-opener-inner {
  background: #fff;
  height: .5rem;
  margin-left: .75rem;
  margin-top: 1.75rem;
  width: 2.5rem;
}
.menu-opener-inner::before, .menu-opener-inner::after {
  background: white;
  content: '';
  display: block;
  height: .5rem;
  width: 2.5rem;
}
.menu-opener-inner::before {
  -webkit-transform: translateY(-0.75rem);
  -ms-transform: translateY(-0.75rem);
  transform: translateY(-0.75rem);
}
.menu-opener-inner::after {
  -webkit-transform: translateY(0.25rem);
  -ms-transform: translateY(0.25rem);
  transform: translateY(0.25rem);
}
.menu-opener-inner.active {
  background: transparent;
}
.menu-opener-inner.active::before {
  -webkit-transform: translateY(0rem) rotate(-45deg);
  -ms-transform: translateY(0rem) rotate(-45deg);
  transform: translateY(0rem) rotate(-45deg);
}
.menu-opener-inner.active::after {
  -webkit-transform: translateY(-0.5rem) translateX(0rem) rotate(45deg);
  -ms-transform: translateY(-0.5rem) translateX(0rem) rotate(45deg);
  transform: translateY(-0.5rem) translateX(0rem) rotate(45deg);
}

.menu {
  background: #f1c40f;
  color: transparent;
  height: 64px;
  position: absolute;
  top: 2%;
  left: 1%;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  width: 0rem;
  z-index: -1;
}
.menu.active {
  width: -webkit-calc(100% - 2rem);
  width: calc(100% - 2rem);
}
.menu.active .menu-link {
  color: white;
}

.menu-inner {
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: horizontal;
  -webkit-box-direction: normal;
  -webkit-flex-direction: row;
  -ms-flex-direction: row;
  flex-direction: row;
  height: 100%;
  list-style-type: none;
  margin: 0;
  margin-left: 4rem;
  padding: 0;
}

.menu-link {
  color: transparent;
  display: -webkit-box;
  display: -webkit-flex;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-flex: 1;
  -webkit-flex: 1 1 auto;
  -ms-flex: 1 1 auto;
  flex: 1 1 auto;
  font-size: 2rem;
  font-weight: 100;
  height: 100%;
  text-align: center;
  text-decoration: none;
}
.menu-link li {
  margin: auto;
}

@media screen and (max-width: 768px) {
  .menu {
    height: auto;
  }
  .menu-inner {
    display: block;
  }
  .menu-link {
    padding: 10px 0;
    font-size: 1.2em;
  }
  .menu.active {
    width: -webkit-calc(100% - 0.5rem);
    width: calc(100% - 0.5rem);
  }
}

$(".menu-opener").click(function(){
  $(".menu-opener, .menu-opener-inner, .menu").toggleClass("active");
});