title: How to use display:block properly with buttons in css?
body: <p>When I use <strong>display:block</strong> it doesn't want to work which was working before. When I inspect it shows me strike through on <strong>display:block</strong>. Now the buttons are positioned on the right side of the col, I'd need them to be positioned in the middle under the image.</p>
  
  <p><strong>html</strong></p>
  
  <pre><code>&lt;div class="sectionLight"&gt;
    &lt;div class="row"&gt;
      &lt;div class="col-sm-12"&gt;
        &lt;div class="row"&gt;
          &lt;div class="col-sm-12 col-lg-4"&gt;
            &lt;img class="img-fluid imgCenter" src="images/square.png"&gt;
            &lt;div class="row"&gt;
              &lt;div class="col-sm-12"&gt;
                &lt;button type="button" class="btn btn-danger btn-lg btnCenter" data-toggle="modal" data-target=".square-modal-lg"&gt;Prime&lt;/button&gt;
              &lt;/div&gt;
            &lt;/div&gt;
          &lt;/div&gt;
          &lt;div class="col-sm-12 col-lg-4"&gt;
            &lt;img class="img-fluid imgCenter" src="images/fibo.png"&gt;
            &lt;div class="row"&gt;
              &lt;div class="col-sm-12"&gt;
                &lt;button type="button" class="btn btn-danger btn-lg btnCenter" data-toggle="modal" data-target=".fibo-modal-lg"&gt;Fibo&lt;/button&gt;
              &lt;/div&gt;
            &lt;/div&gt;
          &lt;/div&gt;
          &lt;div class="col-sm-12 col-lg-4"&gt;
            &lt;img class="img-fluid imgCenter" src="images/square_copy.png"&gt;
            &lt;div class="row"&gt;
              &lt;div class="col-sm-12"&gt;
                &lt;button type="button" class="btn btn-danger btn-lg btnCenter" data-toggle="modal" data-target=".prime-modal-lg"&gt;Square&lt;/button&gt;
              &lt;/div&gt;
            &lt;/div&gt;
          &lt;/div&gt;
        &lt;/div&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p><strong>CSS</strong></p>
  
  <pre><code>.btnCenter {
    display: block;
    margin: auto;
    margin-top: 15px;
    margin-bottom: 20px;
    width: 50%;
  }
  </code></pre>