title: Header, hr and btn at the same line
body: <p>I'm trying to display a header with a hr and a button at the same line. Something like this:</p>
  <p>Header ------------------------------------ Button</p>
  <p><a href="https://i.stack.imgur.com/cYT8W.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/cYT8W.png" alt="See image" /></a>
  I've tried with display flex, but the hr changed for a vertical line.</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>.flex-header {
    display: flex;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="flex-header"&gt;
  &lt;h2&gt; Des habitations pour tous &lt;/h2&gt;
  &lt;hr/&gt;
  &lt;button&gt; Collections &lt;/button&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>