animation-reverde

<div class="intro-wrapper">
  <div id="intro" class="intro"></div>
  <a href="#" id="arrow-link"><span class="arrow"></span></a>
</div>
<div id="content" class="content">
  <div class="menu-centered primary">
    <ul class="menu">
      <li><a href="#">About</a></li>
      <li><a href="#">Portfolio</a></li>
      <li><a href="#">Contact</a></li>
    </ul>
  </div>
  <div class="portfolio row small-up-1 medium-up-3">
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
    <div class="portfolio-item column">
      <img src="https://placehold.it/600x600?text=portfolio+item">
    </div>
  </div>
</div>