.back {
    position: relative;
    height: auto;
}

.image {
    display: block;
    width: 100%;
    height:100%;
    object-fit: cover;/*bu background-size ga oxshagan property, bu rasmni moslashtitrib beradi*/
}

.overlay {
    position: absolute;
    bottom:20%;
    left: 0;
    right: 0;
    overflow: hidden;
    width: 100%;
    height: 0;
    opacity: 0;
    transition: .5s ease;
    z-index: 1;
}
.hover{
    position: absolute;
    bottom:0;
    left: 0;
    right: 0;
    overflow: hidden;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    opacity: 0;
    transition: .5s ease;
}
.back:hover .overlay{
    height: 70%;
    opacity: 1;
}
.back:hover .hover{
    opacity: 1;
}


.overlay-text {
    color: white;
    font-size: 20px;
    position: absolute;
    top: 50%;
    left: 50%;
    -webkit-transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
    text-align: center;
}