:root {
  --layer-legacy: 2000;
  --layer-imagery: 2010;
  --layer-reader: 2025;
  --layer-legacy-foreground: 2050;
  --layer-notices: 2060;
  --layer-screens: 2070;
  --layer-surfaces: 2075;
  --layer-hud: 2100;
  --layer-transitions: 3000;
  --layer-panels: 4000;
  --layer-system: 100000;
  --ui-space-small: 0.5rem;
  --ui-space: 1rem;
  --ui-control: 2.75rem;
  --ui-text: 1rem;
  --ui-label: 0.875rem;
  --ui-panel-duration: 180ms;
}