[ jquery ] 같은 제이쿼리 순서 찾기 ( eq / idx )

$(".con>ul>li").on("click",function(){
         var idx = $(".con>ul>li").index(this);
       $(".con .pop>div").stop().fadeOut(500);
       $(".con .pop>div").eq(idx).stop().fadeIn(500);
       return false;
       });

$(".close").click(function(){
  $(".bk").stop().fadeOut(500);
return false;
});​

<div> 
<section class="con">
    <h3>Click ↓</h3>
    <ul>
        <li><a href="">a</a></li>
        <li><a href="">b</a></li>
        <li><a href="">c</a></li>
        <li><a href="">d</a></li>
    </ul>
    <div class="pop">
      <div class="bk">1<button class="close">닫기</button></div>
        <div class="bk">2<button class="close">닫기</button></div>
        <div class="bk">3<button class="close">닫기</button></div>
        <div class="bk">4<button class="close">닫기</button></div>
     </div>
           
  <div>
</section> 
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>