inline-block vertical centering css

css inline-block fixed height container unknown height content centering

HTML

<svg class="polu" preserveAspectRatio="xMidYMid meet" viewBox="0 0 100 100">
       <a class="polu2" xlink:href="deviantart.com" >
         <polygon class="polu3" fill="red" stroke="brown" points="45,2 2,45 45,88 88,45"/>
       </a>
     </svg>

CSS

.polu {
width: 100px;
height: 100px;
}

JavaScript

(function(){

       "use strict";

       window.onload = function() {
         polygoChk();
       };

       function polygoChk() {
         var polu = document.getElementsByClassName('polu3')[0];
         
         var polyHeight = polu.getAttribute('width');
         
         console.log(polyHeight+ " polygon width");
       };

     })();