anchor.diff:          </a>
         </div>
         <div class="card-reveal">
  -        explanation
  +        <span class="card-title grey-text text-darken-4">
  +          Why is this important?
  +          <i class="material-icons right">close</i>
  +        </span>
         </div>
       </div>
     </div>
  
positive.code:     <div class="card">
        <div class="card-content">
          <div class="card-title">N-syllable words</div>
          <div id="graph-n-syllable-words"></div>
        </div>
      </div>
    </div>
  
negative.code:         </a>
        </div>
        <div class="card-reveal">
          <span class="card-title grey-text text-darken-4">
            Why is this important?
            <i class="material-icons right">close</i>
          </span>
        </div>
      </div>
    </div>
  