title: full width div in bootstrap 4
body: <p>Why is my bottom border in the inside div not full width?</p>
  
  <pre><code>    &lt;div class="container-fluid"&gt;
          &lt;div class="row"&gt;
              &lt;div class="col-12 col-md-2 bg-light mh-100"&gt;
                  &lt;div class="d-flex justify-content-center border-bottom w-100"&gt;
                      &lt;img class="my-3" src="img/img.png" alt="" srcset="" style="height:18px; width:110px;"&gt;
                  &lt;/div&gt;
              &lt;/div&gt;
              &lt;div class="col-12 col-md-10 bg-dark mh-100"&gt;
                  &lt;p&gt;sfsdfsdfsd&lt;/p&gt;
              &lt;/div&gt;
          &lt;/div&gt;
      &lt;/div&gt;
  </code></pre>