title: flexbox positioning, one item at top one at bottom
body: <p>I have a container with 2 items.
  I used flexbox to center them, but I want one of them on the middle, and another one on the bottom, but he has to be center also.</p>
  
  <pre><code>&lt;section class="primary__section"&gt;
      &lt;img class=" primary__section__logo " src=../img/logo_png.png alt=" "&gt;
      &lt;img class=" primary__section__scroll " src=../img/scroll.png alt=" "&gt;
  &lt;/section&gt;
  
  .primary__section {
      background: url("../img/photo_up.png") no-repeat;
      background-size: cover;
      background-position: 50%;
      min-height: 100vh;
      width: 100%;
      display: flex;
      justify-content: center;
      align-items: center;
      flex-direction: column;
  
  &amp;__logo {
      width: 260px;
  }
  </code></pre>