Моя кнопка

HTML

<label class="chbutton">
    <input type="checkbox" />
    <span class="chbutton-sp">
        <span class="ch_inner">
            <span class="ch_left">да</span>
            <span class="ch_right">нет</span>
        </span>
    </span>
</label>

CSS

.chbutton {
  display: inline-block;
  vertical-align: middle;
  white-space: nowrap;
  padding: 0;
  position: relative;
  overflow: hidden;
}
.chbutton-sp {
  font: 20px/1.5em "Helvetica Neue", Arial, sans-serif;
  position: relative;
  z-index: 1;
  display: inline-block;
  background: -webkit-gradient(linear, left top, right top, color-stop(0.5, #3290de), color-stop(0.5, #acacac));
  background: -webkit-linear-gradient(left, #3290de 50%, #acacac 50%);
  background: -moz-linear-gradient(left, #3290de 50%, #acacac 50%);
  background: -o-linear-gradient(left, #3290de 50%, #acacac 50%);
  background: -ms-linear-gradient(left, #3290de 50%, #acacac 50%);
  background: linear-gradient(left, #3290de 50%, #acacac 50%);
  -webkit-background-size: 200% 100%;
  -moz-background-size: 200% 100%;
  background-size: 200% 100%;
  text-align: center;
  -webkit-border-radius: 5px;
  border-radius: 5px;
  height: 1.5em;
  padding: 0 0.9em;
  vertical-align: top;
  cursor: pointer;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  color: #fff;
  text-shadow: 0 -1px 0 rgba(0,0,0,0.75);
  -webkit-transition: background-position 0.3s;
  -moz-transition: background-position 0.3s;
  -o-transition: background-position 0.3s;
  -ms-transition: background-position 0.3s;
  transition: background-position 0.3s;
}
.chbutton-sp:after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  -webkit-box-shadow: inset 0 2px 6px rgba(0,0,0,0.5);
  box-shadow: inset 0 2px 6px rgba(0,0,0,0.5);
  -webkit-border-radius: 5px;
  border-radius: 5px;
}
.ch_inner {
  display: block;
  position: relative;
  left: 0%;
  height: 100%;
  -webkit-transition: left 0.3s;
  -moz-transition: left 0.3s;
  -o-transition: left 0.3s;
  -ms-transition: left 0.3s;
  transition: left 0.3s;
}
.chbutton > input:checked + .chbutton-sp {
  background-position: 100% 0;
}
.chbutton > input:checked + .chbutton-sp > .ch_inner {
  left:...