Scale element when zoom - HTML/CSS

I have an scrollbar which height is 31.25em. Now this looks fine as it is on screen but if I zoom in via the web browser like from 100% to 110%, the scroll bar seems to increase in size. My question is how to scale the scroll bar so that it looks correct after zoom?

.scrollText{

   max-height: 31.25em;
   overflow: auto;
   padding-right: 1em;
   padding-bottom: 2em;
 }