How do I disable the border on bootstrap 4 cards : <p>A grey outline keeps appearing on the img section of my bootstrap card, which I would like to remove. 
 <a href="https://i.stack.imgur.com/sIpIR.png" rel="noreferrer"><img src="https://i.stack.imgur.com/sIpIR.png" alt="Bootstrap card"></a></p>

<pre><code>    &lt;!-- Card deck --&gt;
                &lt;div class="card-deck"&gt;
                    &lt;!-- Card --&gt;
                    &lt;div class="col-md-6 col-lg-4 col-xl-3"&gt;
                        &lt;div class="card mb-4"&gt;
                            &lt;!--Card image--&gt;
                            &lt;div class="view overlay"&gt;&lt;img alt="Work eyewear" class="card-img-top img-fluid" src="img/clothing-1.jpg"&gt;&lt;/div&gt;&lt;!--Card content--&gt;
                            &lt;div class="card-body"&gt;
                                &lt;!--Title--&gt;
                                &lt;h4 class="card-title"&gt;PPE&lt;/h4&gt;&lt;!--Text--&gt;
                                &lt;p class="card-text"&gt;PPE is equipment that will protect the user against health or safety risks at work...&lt;/p&gt;&lt;!-- Provides extra visual weight and identifies the primary action in a set of buttons --&gt;
                                &lt;a class="" href="https://shop.spartansafety.co.uk/personal-protection-s/1820.htm"&gt;SHOP NOW &lt;i class="fas fa-arrow-right fa-xs"&gt;&lt;/i&gt;&lt;/a&gt;
                            &lt;/div&gt;
                        &lt;/div&gt;
                    &lt;/div&gt;&lt;!-- Card --&gt;
</code></pre>
