 0;
  left: 0;
  height: 1.3em;
  width: 1.3em;
  background-color: #ccc;
  border-radius: 100%;
  background: #e8e8e8;
  box-shadow: 3px 3px 5px #c5c5c5,
              -3px -3px 5px #ffffff;
  transition-duration: 0.5s;
}

.container input:checked ~ .checkmark {
  box-shadow: inset 3px 3px 5px #c5c5c5,
              inset -3px -3px 5px #ffffff;
}

.checkmark:after {
  content: "";
  position: absolute;
  opacity: 0;
}

.container input:checked ~ .checkmark:after {
  opacity: 1;
}

.container .checkmark:aft