ade-right-big</h2>
      <button ng-click="dn_fade_right_big=!dn_fade_right_big">Toggle Class</button>
      <div class="element" ng-class="{'dn-fade-right-big':dn_fade_right_big}">
        ...
      </div>
    </section>

    <section>
      <h2>.dn-flip-x</h2>
      <button ng-click="dn_flip_x=!dn_flip_x">Toggle Class</button>
      <div class="element" ng-class="{'dn-flip-x':dn_flip_x}">
        ...
      </div>
    </section>

    <section>
      <h2>.dn-flip-y</h2>
      <button ng-click="dn_flip_y=!dn