body {
  margin: 0;
  font-family: arial;
  width: 100vw;
  height: 100vh;
  animation: bugfix infinite 1s;
  -webkit-animation: bugfix infinite 1s;
}

@keyframes bugfix {
  from {
    padding: 0;
  }
  to {
    padding: 0;
  }
}
@-webkit-keyframes bugfix {
  from {
    padding: 0;
  }
  to {
    padding: 0;
  }
}
#overlay-button {
  position: absolute;
  right: 2em;
  top: 3em;
  padding: 26px 11px;
  z-index: 5;
  cursor: pointer;
  user-select: none;
}
#overlay-button span {
  height: 4px;
  width: 35px;
  border-radius: 2px;
  background-color: white;
  position: relative;
  display: block;
  transition: all .2s ease-in-out;
}
#overlay-button span:before {
  top: -10px;
  visibility: visible;
}
#overlay-button span:after {
  top: 10px;
}
#overlay-button span:before, #overlay-button span:after {
  height: 4px;
  width: 35px;
  border-radius: 2px;
  background-color: black;
  position: absolute;
  content: "";
  transition: all .2s ease-in-out;
}
#overlay-button:hover span, #overlay-button:hover span:before, #overlay-button:hover span:after {
  background: #fff;
}

input[type=checkbox] {
  display: none; 
  
}

input[type=checkbox]:checked ~ #overlay {
  visibility: visible; 
}

input[type=checkbox]:checked ~ #overlay-button:hover span, input[type=checkbox]:checked ~ #overlay-button span {
  background: transparent;
  
  
}
input[type=checkbox]:checked ~ #overlay-button span:before {
  transform: rotate(45deg) translate(7px, 7px);

}
input[type=checkbox]:checked ~ #overlay-button span:after {
  transform: rotate(-45deg) translate(7px, -7px);


}

#overlay {
  height: 100vh;
  width: 100vw;
  background: green;
  z-index: 2;
  visibility: hidden;
  position: fixed;
}
#overlay.active {

}
#overlay ul {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  text-align: center;
  height: 100vh;
  padding-left: 0;
  list-style-type: none;
}
#overlay ul li {
  padding: 1em;
}
#overlay ul li a {
  color: #fff;
  text-decoration: none;
  font-size: 1.5em;
}
#overlay ul li a:hover {
  color: #000!important;
}