.gallery__slider-card a {

}

.gallery__slider-card a::before  {
    content: "";
    display: block;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.5);
    position: absolute;
    bottom: 100%;
    left: 0;
    z-index: 1;
    transition: all .3s ease;
}

.gallery__slider-card span  {
    position: absolute;
    bottom: 100%;
    left: 0;
    z-index: 2;
    text-align: center;
    display: block;
    width: 100%;
    font-style: normal;
    font-weight: 700;
    font-size: 2rem;
    line-height: 140%;
    transition: all .3s ease;
}

.gallery__slider-card a:hover {

}

.gallery__slider-card a:hover::before {
    bottom: 0;
}

.gallery__slider-card a:hover span {
    bottom: 20px;
}