/* Sticky stack — one viewport of scroll per layer until L6 is on top */
:root {
  --stack-nav: 2.5rem;
  --stack-stick: 3rem;
  --stack-tab-h: 1.72rem;
  --stack-step: 1.75rem;
  --stack-gap: 0.35rem;
  /* ~one folder body of scroll between layers (not a full viewport each) */
  --stack-scroll-slot: 1.5rem;
}