.sec_inner .box_list{display: flex;flex-wrap: wrap; gap: 50px; padding: 50px 0;}
.sec_inner .box_list .box {flex: 1 1 30%;}
.sec_inner .img_box {position: relative;overflow: hidden;}
.sec_inner ul li.bottom {margin-top: 100px;}
.sec_inner ul li a {
  position: relative;
  z-index: 1;
  top: 0;
  visibility: hidden;
  opacity: 0;
  -webkit-transition: all 0.6s cubic-bezier(.4,0,.2,1);
  -moz-transition: all 0.6s cubic-bezier(.4,0,.2,1);
  -o-transition: all 0.6s cubic-bezier(.4,0,.2,1);
  transition: all 0.6s cubic-bezier(.4,0,.2,1);
}
.sec_inner ul li.active a {visibility: visible;opacity:1;}

.sec_inner ul li .img_box .back_box {
  width: 100%;
  height: 0;
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 2;
  background-color: #f6f6f6;
  -webkit-transition: all 0.6s 0.6s cubic-bezier(0.165, 0.840, 0.440, 1.000);
  -moz-transition: all 0.6s 0.6s cubic-bezier(0.165, 0.840, 0.440, 1.000);
  -o-transition: all 0.6s 0.6s cubic-bezier(0.165, 0.840, 0.440, 1.000);
  transition: all 0.6s 0.6s cubic-bezier(0.165, 0.840, 0.440, 1.000);
}

.sec_inner ul li.active .img_box .back_box.active{height:100%;top:0!important;}
.sec_inner ul li .img_box .thumb_img {
  position: absolute;
  top: 100%;
  left: 0;
  width: 100%;
  min-width: 100%;
  min-height: 100%;
  display: inline-block;
  -webkit-transition-delay: 1.2s;
  transition-delay: 1.2s;
  -webkit-transition-duration: .7s;
  transition-duration: .7s;
  transition-timing-function: cubic-bezier(0.000, 0.870, 0.000, 0.915);
}
.sec_inner ul li .img_box .thumb_img.active {top: 0 !important;z-index: 2;}