jQuery实现鼠标移入显示蒙版效果

<ul id="fourth_tab">
  <li>
   <img src="img/camera_green.png" alt="绿色相机" class="camera">
   <p class="title"><span>摄影小白成长记</span></p>
   <p>The best preparation for tomorrow is doing your best today.</p>
  </li>
  <li style="background-color: red">
   <div class="show_more"><a href="html/test.html" >点击查看更多</a></div>
   <img src="img/bus.webp" alt="公交车">
  </li>
  <li style="background-color: red">
   <div class="show_more"><a href="html/test.html" >点击查看更多</a></div>
   <img src="img/life.png" alt="落叶">
  </li>
 </ul>

#fourth_tab li{
 position: relative;
 border-radius: 6px;
}
.show_more{
 width: 100%;
 height: 100%;
 line-height: 230px;
 background-color: #9f594d;
 position: absolute;
 display: none;
 font-size: 22px;
 font-weight: bolder;
 letter-spacing: 4px;
 cursor: pointer;
}
.show_more a{
 text-decoration: none;
 color: #fbfff9;
}

$('#fourth_tab li').mouseenter(function(){
 $(this).find('.show_more').slideDown(200);
});

$('#fourth_tab li').mouseleave(function(){
 $(this).find('.show_more').slideUp(200);
});