example.css

@import url(http://fonts.googleapis.com/css?family=Roboto);

* {
  box-sizing: border-box;
}
*:focus {
  outline: 0;
}
body {
  font-family: 'Roboto', Helvetica, sans-serif;
  color: #212121;
  background-color: #e3f2fd;
}

.container {
  text-align: center;
}

span[role="checkbox"] {
  padding: .5em 0;
  display: block;
}

.checkbox {
  display: block;
  zoom: 1;
  overflow: auto;
}
.checkbox button {
  border: 1px solid #212121;
  background-color: #fff;
  width: 16px;
  height: 16px;
  font-size: .8em;
  padding: 0;
  margin: 0;
}
.checkbox label, .custom label {
  padding-left: .5em;
}

.custom button {
  background-color: #FCE4EC;
  width: 16px;
  height: 16px;
  border: 1px solid #880E4F;
  transition-duration: .5s;
}
.custom.checked button {
  background-color: #E91E63;
  box-shadow: 0 2px 10px 0 rgba(0, 0, 0, 0.16), 0 2px 5px 0 rgba(0, 0, 0, 0.26);
  border-radius: 10px;
}