:root {
  @media (prefers-color-scheme: dark) {
    --room-list-background-overlay: hsla(0, 0%, 4%, .8);
    --space-list-background-overlay: hsla(0, 0%, 4%, .7);
    --room-list-background: linear-gradient(in hsl longer hue, red 0 0, magenta);
  }
}