<div class="check-container">
  <h1>Check it!</h1>
  
  <div class="check-row">
    <input type="checkbox" id="check-one" class="hidden" />

    <label class="check-label" for="check-one">

      <div class="check-box">
        <i class="fa fa-square-o check-off"></i><i class="fa fa-check check-on"></i>
      </div>

      One!

    </label>
  </div>
  
  <div class="check-row">
    <input type="checkbox" id="check-two" class="hidden" />

    <label class="check-label" for="check-two">

      <div class="check-box">
        <i class="fa fa-square-o check-off"></i><i class="fa fa-check check-on"></i>
      </div>    

      Two!

    </label>
  </div>
  
  <div class="check-row">
    <input type="checkbox" id="check-three" class="hidden" />

    <label class="check-label" for="check-three">

      <div class="check-box">
        <i class="fa fa-square-o check-off"></i><i class="fa fa-check check-on"></i>
      </div>    

      Three!

    </label>
  </div>
  
</div>

@import "bourbon";

/* check box styles: */
$color: #b4d;
$box-color: darken($color,10);
$check-color: lighten(green,10);

.hidden {
  display: none;
}

.check-label {
  cursor: pointer;
  display: inline-block;
  @include perspective(0);
  @include perspective-origin(center center);
  
  [type=checkbox]:checked + & {
    font-weight: bold;
  }
}

.check-box {
  display: inline-block;
  vertical-align: middle;
  left: 0; top: 0;
  width: 1.5em;
  height: 1.5em;
  @include transition(all 0.25s $ease-in-circ);
  @include transform-style(preserve-3d); 
  
  [type=checkbox]:checked + .check-label & {
    @include transform(rotateX(90deg));
    @include transition(all 0.45s $ease-in-out-back);
  }
}

.check-off, .check-on {
  display: inline-block;
  font-size: 1.5em;
  position: absolute;
  backface-visibility: hidden;
}

.check-off {
  color: $box-color;
  @include transform(translateZ(0.5em));
}

.check-on {
  color: $check-color;
  @include transform(rotateX(-90deg) translateZ(0.5em));
}

/* demo styles: */
* {
  box-sizing: border-box;
}

body {
  margin: 2em 0;
}

.check-container {
  width: 500px;
  margin: 0 auto;
  padding: 1em;
  border-radius: 0.5em;
  border: 4px solid lighten($color,10);
  background: $color;
  color: white;
  
  h1 {
    margin: 0;
    text-align: center;
  }
}

.check-row {  
  padding: 0.5em;
  border-bottom: 1px solid lighten($color,10);
  font-size: 2em;
  
  &:last-child {
    border: none;
  }
}

.check-on {
  text-shadow: 0 0 20px green;
}