Make divs in a row stack on top when screen size is smaller
<p>So i Have two divs that I have figured out how to display horizontally next to eachother in a row with two columns. Once I shrink the screen size they seem to just over lap eachother. I was wondering if there is a quick way to make them stack on top of eachother once the screen size shrinks smaller than a certain size. Really I need the left item to stack on top of the right item. </p>

<p>Here is the html code: </p>

<pre><code>&lt;div id="video-section" align="center"&gt;
      &lt;div class="video"&gt;
        &lt;iframe src="some-video-url" width="100%" height="100%"&gt;&lt;/iframe&gt;
      &lt;/div&gt;
      &lt;div class="bullets"&gt;
        &lt;p&gt; &lt;h4 align="center"&gt;Text&lt;/h4&gt;
        &lt;ul&gt;
        &lt;li&gt;Text&lt;/li&gt;
        &lt;li&gt;Text&lt;/li&gt;
        &lt;li&gt;Text&lt;/li&gt;
        &lt;/ul&gt;
        &lt;/p&gt;
      &lt;/div&gt;
      &lt;div class="clearfix"&gt;&lt;/div&gt;
&lt;/div&gt;
</code></pre>

<p>Here is the css:</p>

<pre><code>#video-section {
        max-width: 1000px;
        margin: 0 auto;
        vertical-align: center;
      }

      .video {
        width: 50%;
        height: auto;
        display: inline-block;
        float: left;
      }

      .bullets {
        width: 50%;
        text-align: left;
        display: inline-block;
        float: right;
      }
</code></pre>

<p>Here are images of what this looks like: </p>

<p><a href="https://i.stack.imgur.com/VNdII.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/VNdII.png" alt="desktop"></a></p>

<p><a href="https://i.stack.imgur.com/bIqXs.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bIqXs.png" alt="mobile"></a></p>

<p>Any help is appreciated, the main goal is to stack these on top of each other once the screen size is smaller. If my code is all wrong as well I am very open to changing all of it if someone thinks that there is a more efficient way of doing this. </p>

<p>To give all information necessary, I am doing this in sublime text, using the polymer library with paper elements, and deploying this to a firebase hosting server. </p>