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

/* Compose's canvas lets the browser pan it (touch-action: pan-x pan-y), and a gesture the browser
   takes (e.g. one started sideways, locked to a pan with nothing to move) is lost to Compose's own
   scrolling. Touch-action narrows down the tree, so none on the viewport's container (the body's
   only div) leaves every gesture to Compose. */
body > div {
    touch-action: none;
}