html, body {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
    overflow: hidden;
}

/* The surface colour of the theme the app is about to draw in, so the page it loads on does not
   flash white before a dark app. data-theme is the choice made in Settings, set by index.html;
   without one, or with System, the device decides. */
body {
    background: #F5FAFD;
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="Light"]) body {
        background: #0F1416;
    }
}

:root[data-theme="Dark"] body {
    background: #0F1416;
}