title: justify-content-md-center not working?
body: <p>I'm following a tutorial and I want to use justify-content-md-center when it reaches medium screen size. But it doesnt seem to work.</p>
  
  <pre><code> &lt;div class="container"&gt;
      &lt;div class="row" style="background:lightblue"&gt;
        &lt;div class="col-md-2"&gt;col-sm-6&lt;/div&gt;
        &lt;div class="col-md-8"&gt;col-sm-6&lt;/div&gt;
        &lt;div class="col-md-2"&gt;col-sm-6&lt;/div&gt;
      &lt;/div&gt;
        &lt;div class="row justify-content-md-center"&gt;
          &lt;div class="col-md-2"&gt;col-sm-2&lt;/div&gt;
          &lt;div class="col-md-2"&gt;col-sm-2&lt;/div&gt;
          &lt;div class="col-md-2"&gt;col-sm-2&lt;/div&gt;
        &lt;/div&gt;
  
    &lt;/div&gt;
  </code></pre>
  
  <p>I appreciate the help thanks</p>