*{
  box-sizing:border-box;
  margin:0;
  padding:0;
}
html,
body {
  height:100vh;
  display:flex;
  align-items:center;
  justify-content:center;
  background-color: #212121;
}
.button {
  display: inline-block;
  width: 50px;
  height: 20px;
  background-color: #fff;
  border-radius: 30px;
  cursor: pointer;
  padding: 0;
  color: white;
}

#toggle {
  display: none;
}

.slider {
  display: block;
  font-size: 10px;
  position: relative;
}

.slider::after {
  content: 'OFF';
  width: 25px;
  height: 25px;
  background-color: #e03c3c;
  border: 2px solid #fff;
  border-radius: 50%;
  box-shadow: 0 0 5px rgba(0, 0, 0, .25);
  position: absolute;
  top: -5px;
  left: 0;
  display: grid;
  place-content: center;
  line-height: 0;
  transition: background-color .25s, transform .25s ease-in;
}

#toggle:checked + .slider::after {
  content: 'ON';
  background-color: #05ae3e;
  transform: translateX(25px) rotate(360deg);
}