body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    margin: 20px;
    padding: 20px;
}

#content {
    animation: bounce 0.5s infinite alternate;
}

@keyframes bounce {
    0% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-20px);
    }
    100% {
        transform: translateY(0);
    }
}