body {
    margin: 0;
    text-align: center;
    background-color: black;
    color: white;
    font-family: Helvetica, Arial, sans-serif;
    padding-bottom: 100px;
}
img {
    max-width: 600px;
    max-height: 600px;
    height: auto;
    margin: 250px auto;
    display: block;
}
a {
    color: white;
}
@media screen and (max-width: 768px) {
    img {
        max-width: 90vw;
        height: auto;
    }
}