我尝试创建一个CSS动画，当你悬停在方框上时，它会显示使用CSS动画的div。我使用了以下站点作为参考。点击这里，但我似乎无法实现EFX。在我的站点上，我使用JqUERY实现了一个show and hide函数，我的addClass和RemoveClass可以正常工作，但总体来说，该函数并没有正常工作。有人能指引我正确的方向吗。

/**HTML**/

div class="box">
        <div class="trigger">hhh</div>
            <div class="overlay">
                <h1>box 1</h1>
            </div>
        </div>

<div class="box">
<div class="trigger">hhh</div>
      <div class="overlay">
            <h1>box 1</h1>
        </div>
    </div>

<div class="box">
<div class="trigger">hhh</div>
    <div class="overlay">
            <h1>box 1</h1>
        </div>
    </div>

/*jquery**/

                     $(".overlay").addClass("visible");
        $(".overlay").removeClass("visible");
            $(".trigger").hover(function(){
                var $this = $(this);
                $this.next(".overlay").addClass("visible");
            }); 

            $(".trigger").mouseleave(function(){
                var $this = $(this);
                $this.next(".overlay").removeClass("visible");
            }); 

/**CSS动画**/

.fadeInDown {
-webkit-animation-name: fadeInDown;
-moz-animation-name: fadeInDown;
-o-animation-name: fadeInDown;
animation-name: fadeInDown;
-webkit-animation-duration: 1s;
-webkit-animation-delay: 2s;
-webkit-animation-timing-function: ease;
-webkit-animation-fill-mode: both;

-moz-animation-duration: 1s;
-moz-animation-delay: 2s;
-moz-animation-timing-function: ease;
-moz-animation-fill-mode: both;

-o-animation-duration: 1s;
-o-animation-delay: 2s;
-o-animation-timing-function: ease;
-o-animation-fill-mode: both;

animation-duration: 1s;
animation-delay: 2s;
animation-timing-function: ease;
animation-fill-mode: both;
    }


     @-webkit-keyframes fadeInDown {
0% {
    opacity: 0;
    -webkit-transform: translateY(-20px);
}

100% {
    opacity: 1;
    -webkit-transform: translateY(0);
}
      }


     .fadeInUp {
-webkit-animation-name: fadeInUp;
-moz-animation-name: fadeInUp;
-o-animation-name: fadeInUp;
animation-name: fadeInUp;
-webkit-animation-duration: 1s;
-webkit-animation-delay: 2s;
-webkit-animation-timing-function: ease;
-webkit-animation-fill-mode: both;

-moz-animation-duration: 1s;
-moz-animation-delay: 2s;
-moz-animation-timing-function: ease;
-moz-animation-fill-mode: both;

-o-animation-duration: 1s;
-o-animation-delay: 2s;
-o-animation-timing-function: ease;
-o-animation-fill-mode: both;

animation-duration: 1s;
animation-delay: 2s;
animation-timing-function: ease;
animation-fill-mode: both;
        }

      @-Webkit-keyframes fadeInUp {
0% {
    opacity: 0;
    -moz-transform: translateY(20px);
}