html,body{
    width:100%;
    height:100%;
    margin:0;
    padding:0;
    background:#fff;
    color:#222;
}

body{
    display: flex;
    align-items: center;
    justify-content: center;
}
div{
    padding:1em;
}
img{
    width:20em;
    margin:2em;
}
@media screen and (max-width: 480px) {
    img{
        width:16em;
    }
}