my index.html body
<body>
  <div id='game'>
    <div id='top'>
      <div id='pane1'>
        <div><img src='images/computer.png'></div>
        <div id='computer'>0</div>
      </div>
      <div id='pane2'>
        <div id='grid'>
          <script>squares(); setup();</script>
        </div>
      </div>
      <div id='pane3'>
        <div><img src='images/player.png'></div>
        <div id='player'>0</div>
      </div>
    </div>
    <div id='bottom'>
      <div id='message'>the first to make XXX loses</div>
    </div>
  </div>
</body>
additions to my styles.css
#top, #pane1, #pane2, #pane3, #bottom {
  display:flex;
  justify-content:center;
  align-items:center;
}
#pane1, #pane3 {
  flex-direction:column;
}
#pane1 img, #pane3 img {
  height:20vmin;
}
#game {
  font-size:4vmin;
}
#pane2 {
  padding:2vmin;
}