SOURCE

<div class="cntr">
    <input type="checkbox" id="unchecked" class="cbx hidden"/>
    <label for="unchecked" class="lbl"></label>    
</div>

body {
  background: #181818;
}
* {
  box-sizing: border-box;
}
.lbl {
  position: relative;
  display: block;
  height: 22px;
  width: 40px;
  background: #000;
  border-radius: 100px;
  cursor: pointer;
  border: 2px solid #404040;
  transition: all 0.2s ease;
}
.lbl:after {
  position: absolute;
  left: -2px;
  top: -2px;
  display: block;
  width: 22px;
  height: 22px;
  border-radius: 100px;
  background: #a0a0a0;
  box-shadow: 0 1px 2px rgba(0,0,0,0.4);
  content: '';
  transition: all 0.3s ease;
}
.lbl:active:after {
  width: 26px;
  background: #fff;
}
.cbx:checked ~ label {
  background: #1db955;
  border-color: #1db955;
}
.cbx:checked ~ label:after {
  transform: translateX(18px);
  background: #fff;
}
.cbx:checked ~ label:active:after {
  transform: translateX(14px);
}
.cntr {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
.hidden {
  display: none;
}