title: How to set a custom size to FAB in Ionic v4?
body: <p>I'm creating a floating action button using Ionic 4, and I want to make it bigger.
  If I give the button a class and go to the scss file to change the height and width, the position is messing up (I use center both horizontally and vertically), it changes the size but makes the button START at the center of the screen and drop down from there and not actually centered (hope it made sense right there)</p>
  
  <p>How do I do this correctly? All of the answers on the web are irrelevant to v4 unfortunately</p>
  
  <p>here is my code for the html:</p>
  
  <pre class="lang-html prettyprint-override"><code>  &lt;ion-fab vertical="center" horizontal="center" slot="fixed"&gt;
      &lt;ion-fab-button color="primary" [routerLink]="['/timer']" class="start-btn"&gt;&lt;p&gt;Start&lt;/p&gt;
      &lt;/ion-fab-button&gt;
    &lt;/ion-fab&gt;
  </code></pre>
  
  <p>And the code for the css file:</p>
  
  <pre class="lang-css prettyprint-override"><code>  .start-btn {
      width: 100px;
      height: 100px;
    }
  
  </code></pre>
  
  <p>I need the size to change AND the position to stay as expected</p>
  
  <p>Thanks in advance!</p>