.card{
    border: none;
}

.card-img-overlay {
 position: relative;
}

#Portfolio .card::before{
    content: "";
    background: rgba(0, 0, 0, 0.5);
    position: absolute;
    top: 0;
    width: 100%;
    height: 100%;
}

#Portfolio .card:hover::before{
   content:none ;
}