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

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

    <section>
      <h2>.dn-f