Ankhena

position: absolute;
  top: 50%;
  transform: translateY(-50%);

$('.catalog_box h3').click(function () {
    $('.menur').slideToggle('slow');
    $(this).toggleClass("active")
});

<span contenteditable="true">0</span>

span {
  display: inline-block;
  min-width: 70px;
  outline: 1px solid #999;
}
span::after {
  display: inline-block;
  content: "i";
  width: 15px;
  height: 15px;
  line-height: 15px;
  background: skyblue;
  text-align: center;  
}