.input {
  -webkit-appearance: none;
  /* remove default */
  margin: 6px;
  width: 24px;
  height: 24px;
  border-radius: 12px;
  cursor: pointer;
  vertical-align: middle;
  box-shadow: hsla(0, 0%, 100%, 0.15) 0 1px 1px,
    inset hsla(0, 0%, 0%, 0.5) 0 0 0 1px;
  background-color: hsla(0, 0%, 0%, 0.2);
  background-repeat: no-repeat;
  -webkit-transition: background-position 0.15s cubic-bezier(0.8, 0, 1, 1),
    -webkit-transform 0.25s cubic-bezier(0.8, 0, 1, 1);
  outline: none;
}

.input.green {
  background-image: -webkit-radial-gradient(
    hsla(118, 100%, 90%, 1) 0%,
    hsla(118, 100%, 70%, 1) 15%,
    hsla(118, 100%, 60%, 0.3) 28%,
    hsla(118, 100%, 30%, 0) 70%
  );
}

.input.yellow {
  background-image: -webkit-radial-gradient(
    hsla(50, 100%, 90%, 1) 0%,
    hsla(50, 100%, 70%, 1) 15%,
    hsla(50, 100%, 60%, 0.3) 28%,
    hsla(50, 100%, 30%, 0) 70%
  );
}

.input.red {
  background-image: -webkit-radial-gradient(
    hsla(0, 100%, 90%, 1) 0%,
    hsla(0, 100%, 70%, 1) 15%,
    hsla(0, 100%, 60%, 0.3) 28%,
    hsla(0, 100%, 30%, 0) 70%
  );
}

.input:checked {
  -webkit-transition: background-position 0.2s 0.15s cubic-bezier(0, 0, 0.2, 1),
    -webkit-transform 0.25s cubic-bezier(0, 0, 0.2, 1);
}

.input:active {
  -webkit-transform: scale(1.5);
  -webkit-transition: -webkit-transform 0.1s cubic-bezier(0, 0, 0.2, 1);
}

/* The up/down direction logic */

.input,
.input:active {
  background-position: 24px 0;
}

.input:checked {
  background-position: 0 0;
}

.input:checked ~ .input,
.input:checked ~ .input:active {
  background-position: -24px 0;
}