title: Trouble aligning items with flexbox
body: <p><code>enter code here</code>I can't really explain it better than this code example.</p>
  
  <p><a href="https://codepen.io/anon/pen/BYeger" rel="nofollow noreferrer">https://codepen.io/anon/pen/BYeger</a></p>
  
  <p>I want to make <code>#thing_down_here</code> touch <code>#thing_up_here</code>, but I can't figure out the right combination.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>html, body {
    margin: 0;
    padding: 0;
  }
  
  * {
    box-sizing: border-box
  }
  
  #parent {
    width: 100vw;
    height: 100vh;
    background: cornsilk;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
  }
  
  #thing_up_here {
    flex: 1 0 100%;
    background: skyblue;
    height: 80px;
  }
  
  #thing_down_here {
    flex: 0 0 50%;
    background: lightgreen;
    height: 100px;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div id="parent"&gt;
  &lt;div id="thing_up_here"&gt;&lt;/div&gt;
  &lt;div id="thing_down_here"&gt;&lt;/div&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>