.customCard{
 width: 15rem;
 height: 7rem;
 background-color: blue;
 color:#eee;
}

<div class="card-deck">
    <div class="card-block ">
      <div class="card customCard  mt-2 customCursorPointer">
        <div class="card-body">
        <div class="container d-flex r h-100">
          <div class="row justify-content-center mx-auto align-items-center">
              <h4 class="card-title">AAAA</h4>
          </div>
        </div>
        </div>
      </div>
    </div>
</div>