stylus/options/onoffswitch.css

/* On/Off FlipSwitch https://proto.io/freebies/onoff/ */

.onoffswitch {
  position: relative;
  margin: 1ex 0;
  -moz-user-select: none;
  user-select: none;
}

.onoffswitch input {
  -webkit-appearance: none;
  -moz-appearance: none;
  cursor: pointer;
  position: absolute;
  top: -8px;
  bottom: -10px;
  left: -10px;
  width: calc(100% + 12px);
  border: 0;
}

#message-box .onoffswitch input {
  top: -6px;
  left: -6px;
  bottom: 0;
  height: calc(100% + 12px);
}

.onoffswitch span {
  display: block;
  overflow: hidden;
  height: 12px;
  padding: 0;
  line-height: 12px;
  border: 0 solid #E3E3E3;
  border-radius: 12px;
  background-color: #E0E0E0;
  box-shadow: inset 2px 2px 4px rgba(0,0,0,0.1);
  pointer-events: none; /* this is just a non-clickable decoration, only `input` is clickable */
}

.onoffswitch span::before {
  content: "";
  display: block;
  width: 18px;
  height: 18px;
  margin: -3px;
  background: #efefef;
  position: absolute;
  top: 0;
  bottom: 0;
  right: 46px;
  border-radius: 18px;
  box-shadow: 0 3px 13px 0 rgba(0, 0, 0, 0.4);
}

.onoffswitch input:checked + span {
  background-color: #CAEBE3;
}

.onoffswitch input:checked + span, .onoffswitch input:checked + span::before {
  border-color: #CAEBE3;
}

.onoffswitch input:checked + span .onoffswitch-inner {
  margin-left: 0;
}

.onoffswitch input:checked + span::before {
  right: 0;
  background-color: #04BA9F;
  box-shadow: 3px 6px 18px 0 rgba(0, 0, 0, 0.2);
}