.pro_category li a .img{
    position: relative;
    overflow: hidden;
    width: 100%;
    padding-bottom: 80%;
    background-color: #fff;
}
.pro_category li a .img img{
    position: absolute;
    top: 50%;
    left: 50%;
    display: block;
    width: 95%;
    height: 95%;
    transform: translate(-50%,-50%);
    -o-object-fit: contain;
    object-fit: contain;
    -webkit-transition: all 0.3s;
    -o-transition: all 0.3s;
    -moz-transition: all 0.3s;
    transition: all 0.3s;
}