title: Prevent flex items from stretching
body: <p>Sample:
  <div class="snippet" data-lang="js" data-hide="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>div {
    display: flex;
    height: 200px;
    background: tan;
  }
  span {
    background: red;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div&gt;
    &lt;span&gt;This is some text.&lt;/span&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p>I have two questions, please:</p>
  
  <ol>
  <li>Why does it basically happen to the <code>span</code>?</li>
  <li>What is the right approach to prevent it from stretching without affecting other flex items in a flex container?</li>
  </ol>