Centre the text in the fixed width/height div

Question

How can I centre the text in the div. The height and width of the div is fixed and the text is dynamic. I want to centre that text

   <div id="summary" class="productSummary"></div>
   .productSummary { 
   font-family:: "Proxima Nova Bold", Helvetica, Arial, sans-serif;
   display: inline-block;
   width: 296px;
   max-height: 69px;
   height: auto !important;
   min-height: 69px;
   font-size: 15px;
   color: #000000;
   }