.button_container {
  position:absolute;
  top: 50px;
  right: 5%;
  height: 25px;
  width: 30px;
  cursor: pointer;
  z-index: 100;
  transition: opacity .25s ease;
}
.button_container:hover {
  opacity: .7;
}
.button_container.active .top {
  transform: translateY(11px) translateX(0) rotate(45deg);
  background: #FFF;
}
.button_container.active .middle {
  opacity: 0;
  background: #FFF;
}
.button_container.active .bottom {
  transform: translateY(-11px) translateX(0) rotate(-45deg);
  background: #FFF;
}
.button_container span {
  background: #000;
  border: none;
  height: 2px;
  width: 100%;
  position: absolute;
  top: 0;
  left: 0;
  transition: all .35s ease;
  cursor: pointer;
}
.button_container span:nth-of-type(2) {
  top: 11px;
}
.button_container span:nth-of-type(3) {
  top: 22px;
}

.overlay {
  position: fixed;
  background-color:rgba(0, 0, 0, 0);
  top: 0;
  left: 0;
  width: 100%;
  height: 0%;
 /* opacity: 0;*/
  visibility: hidden;
  transition: opacity .35s, visibility .35s, height .35s;
  overflow: hidden;
  z-index: 99;
}
.overlay.open {
  background-color:rgba(0, 0, 0, 0.9);
  visibility: visible;
  height: 100%;
}
.overlay.open li {
  animation: fadeInRight .5s ease forwards;
  animation-delay: .35s;
}
.overlay.open li:nth-of-type(2) {
  animation-delay: .4s;
}
.overlay.open li:nth-of-type(3) {
  animation-delay: .45s;
}
.overlay.open li:nth-of-type(4) {
  animation-delay: .50s;
}
.overlay nav {
	position: relative;
	height:50%;
	top: 50%;
	transform: translateY(-50%);
	font-size:3.07em; /* 40px; */
	font-family: 'DINPro';
	font-weight: 300;
	text-align: center;
}
.overlay ul {
	list-style: none;
	padding: 0;
	margin: 0 auto;
	display: inline-block;
	position: relative;
	height: 100%;
}
.overlay ul li {
  display: block;
  height: 25%;
  height: calc(100% / 4);
  min-height: 40px;
  line-height:50px;
  position: relative;
  opacity: 0;
}
.overlay ul li a {
  display: block;
  position: relative;
  color: #FFF;
  text-decoration: none;
  overflow: hidden;
}
.overlay ul li a:hover:after, .overlay ul li a:focus:after, .overlay ul li a:active:after {
  width: 100%;
}
.overlay ul li a:after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 0%;
  transform: translateX(-50%);
  height: 3px;
  background: #FFF;
  transition: .35s;
}

@keyframes fadeInRight {
  0% {
    opacity: 0;
    left: 20%;
  }
  100% {
    opacity: 1;
    left: 0;
  }
}


/* Layout landscape: da 769 px a 1024 px max.  Eredita stili da: Layout mobile e Layout tablet portrait */
@media only screen and (min-width: 769px ) {
.button_container, .overlay nav,.overlay {
	display:none;
}
}