将类别添加到Wordpress上的切换复选框父级

Question

我目前正在Wordpress网站上工作，但无法获得有效的复选框JS代码，无法向自己的父元素添加checked类。

该代码段运行良好，但是为什么在我的Wordpress网站上却不起作用？

$(":checkbox").on('click', function() {
  $(this).parent('span').toggleClass("checked");
});

span.cb-style input[type=checkbox] {
  cursor: pointer;
  background: 0 0;
  position: relative;
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  float: left;
  border: none;
  opacity: 0;
}

span.cb-style {
  cursor: pointer;
  display: inline-block;
  width: 18px;
  height: 18px;
  position: relative;
  top: 4px;
  border: 3px solid #ddd;
  background: #fff;
  visibility: visible;
  margin-right: 10px
}

span.cb-style:hover {
  background: #ddd
}

.checked {
  background-color: #ff0000!important;
  border-color: #ff0000!important;
}

.checked:after {
  font-family: "Font Awesome 5 Free";
  content: 'x';
  color: white;
  position: absolute;
  font-size: 25pt;
  left: 0;
  right: 0;
  bottom: 0;
  top: 0;
  margin: -75% auto;
  pointer-events: none;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="tnp-field tnp-field-checkbox tnp-field-privacy">
  <span class="cb-style">
    <input type="checkbox" name="ny" required="" class="tnp-privacy" id="tnp-privacy">
  </span>
  <label for="tnp-privacy">
    <a target="_blank" href="#">Checkbox Sample Text Bla.</a>
  </label>
</div>