CSS: Shadow in a triangle
<p>I have this triangle in CSS:</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>.triangle {
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 200px 200px 0 0;
  border-color: #007bff transparent transparent transparent;
}</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;div class="triangle"&gt;&lt;/div&gt;</code></pre>
</div>
</div>
</p>

<p>How can I apply a 1px shadow on the hypotenuse line?</p>