title: how to avoid the top: -30px in bootstrap?
body: <p>I use a spinner</p>
  <pre><code>&lt;div class=&quot;module-loader2&quot; style=&quot;position: relative; top: -30px; margin: 0 auto;&quot; &gt;
     &lt;div class=&quot;loader-bubble loader-bubble-primary d-block&quot;&gt;&lt;/div&gt;
  &lt;/div&gt;
  </code></pre>
  <p>I would like to avoid the following properties:</p>
  <pre><code>style=&quot;position: relative; top: -30px; margin: 0 auto;&quot; &gt;
  </code></pre>
  <p>What is the property in bootsrap to replace <code>top:-30</code> and <code>margin: 0 auto</code>, please?</p>