html, body {
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
    /*
     * No min-width — the WebMainScreen Compose composable picks a
     * Portrait or Landscape layout based on actual viewport aspect
     * ratio at runtime, so a narrow mobile browser gets a vertical
     * spinner UX rather than a horizontally-scrolled desktop layout.
     */
    overflow: hidden;
}