.card-hover {
    position: relative;
    width: 300px; /* ajustá */
    overflow: hidden;
}

.card-hover img {
    width: 100%;
    display: block;
    transition: opacity 0.3s ease;
}

.img-hover {
    position: absolute;
    top: 0;
    left: 0;
    opacity: 0;
}

.card-hover:hover .img-hover {
    opacity: 1;
}

.card-hover:hover .img-normal {
    opacity: 0;
}