:root {
    --bg-color-from: rgb(64, 64, 64);
    --bg-color-to: rgb(12, 12, 12);

    --app-width: 640;
    --app-height: 640;
}
html, body, * {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
html, body {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    background-color: var(--bg-color-to);
}
body {
    /* background-image: linear-gradient(to bottom,
        var(--bg-color-from) 25%,
        var(--bg-color-to) 75%
    ); */
    padding: 1rem;
    background-image: linear-gradient(to bottom,
        var(--bg-color-from),
        var(--bg-color-to)
    );
}
body main canvas {
    width: 100% !important;
    height: 100% !important;
    object-fit: contain;

    max-width: calc(var(--app-width) * 1px);     
    max-height: calc(var(--app-height) * 1px);
    aspect-ratio: calc(var(--app-width) / var(--app-height));
}