Button will not react to padding or margin in CSS

I'm having an issue getting one of my buttons to react to either padding or margin in CSS. The button stays at the very bottom of the div and does not react to any type of padding or margin within the class I assigned to the div.

HTML

<div class="topBorder">
<h1>Matt</h1>
<a href="#" class="aboutButton">ABOUT</a>
</div>

CSS

.aboutButton {
      color: white;
      padding: 800px;
      font-size: 20px;
      font-family: 'Ubuntu';
}

Current Look