body {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100vh;
}

div.page {
    display: flex;
    align-items: center;
}

.pic {
    background-image: url("404.png");
    min-width: 512px;
    min-height: 512px;
    background-size: contain;
}