Small CSS edit not working in clientareahome.tpl

[Logman]

We use a theme called Hexa. In clientareahome.tpl I'm trying to change the colors of the INVOICES box to green and ORDER NOW to purple. The box is governed by bg-info-dark in city.min.css. I added:

.bg-info-purple{background:#8175C7!important;}

And in clientareahome.tpl:

<div class="col-md-4">
 <a title="{$LANG.ordernowbutton}" href="cart.php">
  <div class="info-box bg-info text-white">
   <div class="info-icon bg-info-purple">
    <span aria-hidden="true" class="icon icon-plus"></span>
  </div>

But doesn't work. Any ideas?