gistfile1.txt

.button {
  position: absolute;
  margin-left: -9999px;
  visibility: hidden;
}
.button + label {
  display: block;
  position: relative;
  cursor: pointer;
  outline: none;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

input.button + label {
  padding: 2px;
  width: 120px;
  height: 60px;
}
input.button + label:before, input.button + label:after {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  color: #fff;
  font-size: 20px;
  text-align: center;
  line-height: 60px;
}
input.button + label:before {
  background-color: #ddd;
  content: attr(data-off);
  transition: transform 0.5s;
  backface-visibility: hidden;
}
input.button + label:after {
  background-color: #8ce196;
  content: attr(data-on);
  transition: transform 0.5s;
  transform: rotateY(180deg);
  backface-visibility: hidden;
}
input.button:checked + label:before {
  transform: rotateY(180deg);
}
input.button:checked + label:after {
  transform: rotateY(0);
}