Pure CSS3 Switch Button with Smooth Animation

An amazing effect created only with CSS3 that converts a standard Html checkbox into a toggle button with smooth switching effects.

How to use it:

Create a standard Html checkbox input.

<input type="checkbox">

The CSS.

/* Face Toggle --------------------------------- */
input[type="checkbox"] {
  appearance: none;
  outline: none;
  position: relative;
  margin: auto;
  cursor: pointer;
  width: 10em;
  height: 5em;
  box-sizing: content-box;
  border-radius: 3em / 2.5em;
  box-shadow: 0 3em 2em hsla(0,0%,0%,.1);
  background: hsl(220,20%,36%);
  transition: transform .2s, background .3s;
  transform: perspective(200) rotateY(45deg);
}
input[type="checkbox"]:checked {
  background: hsl(220,80%,70%);
  transform: perspective(200) rotateY(-45deg);
}
input[type="checkbox"]:active {
  transform: perspective(200) scale(.8, .6);
}
/* eye --------------------------------- */
input[type="checkbox"]:after {
  content: "";
  position: absolute;
  width: 4em;
  height: 3em;
  top: 1em;
  left: 1em;
  background-repeat: no-repeat;
  cursor: pointer;
  border-radius: 4em / 3em;
  background-color: hsl(220,20%,20%);
  box-shadow: 0 .2em .5em hsla(0,0%,0%,.2);
  opacity: 0;
  transform: scale(.8, .01);
  transition: opacity .2s, transform .2s;
}
/* eye open --------------------------------- */
input[type="checkbox"]:checked:after {
  background-image: radial-gradient(hsl(220,80%,20%) 15%, hsl(220,80%,80%) 20%, 
    hsl(220,80%,66%) 40%, hsl(220,80%,96%) 44%, 
    hsl(220,80%,80%) );
  opacity: 1;
  transform: translate3d(4em,0,0) scale(1);
}
/* eye poked --------------------------------- */
input[type="checkbox"]:active:after {
  opacity: .5;
  transform: translate3d(2em,0,0) scale(.6, .1);
}
/* txt --------------------------------- */
input[type="checkbox"]:before {
  content: "×";
  position: absolute;
  width: 1.2em;
  top: 0;
  left: .5em;
  font-size: 3em;
  line-height: 1.5;
  color: hsl(220,20%,20%);
  transition: opacity .2s, transform .2s;
}
input[type="checkbox"]:checked:before {
  opacity: 0;
  transform: translate3d(1.5em,0,0);
}
input[type="checkbox"]:active:before {
  opacity: .5;
  transform: translate3d(.8em,0,0);
}
/* BG --------------------------------- */
body {
  display: flex;
  padding: 50px;
  box-sizing: border-box;
  height: 100%;
  background: hsl(220,10%,20%);
  backface-visibility: hidden;
}
html {
  height: 100%;
}