microw8/web/src/run-web.css

html, body, canvas {
    padding: 0;
    margin: 0;
    background-color: #202024;
}

html {
    height: 100%;
}

body {
    height: 100%;
    display: grid;
    grid-template-rows: 1fr;
}

#screen {
    align-self: center;
    justify-self: center;
    image-rendering: pixelated;
    border: 4px solid #303040;
}

#message {
    position: absolute;
    width: calc(100% - 16px);
    background-color: rgba(0, 0, 0, 0.4);
    color: #c64;
    padding: 8px;
    font: bold 12pt sans-serif;
    z-index: 2;
}

@media (min-width: 648px) and (min-height: 488px) {
    #screen {
        width: 640px;
        height: 480px;
    }
}

@media (min-width: 968px) and (min-height: 728px) {
    #screen {
        width: 960px;
        height: 720px;
    }
}