title: why my css flexbox isn't affecting my div even though it worked on other section
body: <p>I'm trying to align a text <code>div</code> and picture <code>div</code> next to each other using flexbox and, even though I did the same thing before and it worked perfectly, this time for some reason it's not working.</p>
  
  <p>This my HTML and CSS code:</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>.hero-introduction {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    flex: 1 1 40rem;
  }
  
  .hero-images {
    flex: 1 1 40rem;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;section class="hero"&gt;
    &lt;div class="hero-introduction"&gt;
      &lt;h2&gt;Elena Joy &lt;br&gt; Photography&lt;/h2&gt;
      &lt;p&gt;paragraphe here&lt;/p&gt;
      &lt;a href="#gallery"&gt;Gallery&lt;/a&gt;
    &lt;/div&gt;
    &lt;div class="hero-images"&gt;
      &lt;img class="hero-elena" src="images/elena-joy.png" alt="picture of elena joy"&gt;
    &lt;/div&gt;
  
  &lt;/section&gt;</code></pre>
  </div>
  </div>
  </p>