Style is not being applied to H1 element in CSS
<p>I'm facing a strange problem, the  style is not being applied to the <code>H1</code> element.</p>

<p>Code: </p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true">
<div class="snippet-code">
<pre class="snippet-code-css lang-css prettyprint-override"><code>p h1 {
  color: red;
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;p&gt;
  &lt;h1&gt;This is a header&lt;/h1&gt;
&lt;/p&gt;</code></pre>
</div>
</div>
</p>