Edit in JSFiddle

<div class="center">
  <input type="checkbox">
</div>

.center {
  position: absolute;
  top: 50%;
  left: 50%;
  -webkit-transform: translate(-50%, -50%);
  -moz-transform: translate(-50%, -50%);
  -ms-transform: translate(-50%, -50%);
  -o-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
}

input {

  &[type="checkbox"] {
    position: relative;
    width: 80px;
    height: 40px;
    background: #ccc;
    outline: none;
    border-radius: 20px;
    -webkit-appearance: none;
    -moz-appearance: none;
    appearance: none;

    &:before {
      content: '';
      position: absolute;
      width: 36px;
      height: 36px;
      border-radius: 20px;
      top: 2px;
      left: 2px;
      background: #fff;
      -webkit-transition: .2s;
      -moz-transition: .2s;
      -ms-transition: .2s;
      -o-transition: .2s;
      transition: .2s;
    }

    &:checked {
      background: #03a9f4;

      &:before {
        left: 42px;
      }
    }
  }
}