body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
}

header, footer {
    background: #1eff00;
    color: white;
    text-align: center;
    width: 100%;
    padding: 10px;
}

.gallery {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 10px;
    padding: 20px;
}

.image-box {
    width: 400px;
    height: 300px;
    overflow: hidden;
    position: relative;
    border-radius: 10px;
}

.image-box img {
    width: 100%;
    height: 100%;
    position: absolute;
    top: 0;
    left: 0;
    transition: opacity 0.3s ease-in-out;
}

.image-box img:first-child {
    opacity: 1;
}

.image-box img:last-child {
    opacity: 0;
    transition: opacity 0.3s ease-in-out;
}

.image-box:hover img:first-child {
    opacity: 0;
}

.image-box:hover img:last-child {
    opacity: 1;
}