html, body {
    display: flex;
    width: 100%;
    height: 100%;
    background-color: transparent;
    margin: 0;
}
article {
    min-height: 100%;
    min-width: 100%;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    justify-content: center;
}
main {
    flex-grow: 1;
}
header, main, footer {
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
}
button {
    min-height: 32px;
}
audio {
    width: 100%;
}
img {
    object-fit: contain;
    height:0;
    min-height:100%;
}