.portfolio-item {
    width: 100%;
}

.image-container {
    width: 100%;
    height: 400px; /* Initial visible height */
    overflow: hidden;
    position: relative;
}

.image-container img {
    width: 100%;
    position: absolute;
    top: 0;
    left: 0;
    transition: top 3s ease;
}