OptionalchildrenOptionalclassClass for the marquee visuals (devtools identification).
OptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalonOptionalstyleStyle for the layer's boundary div — e.g. display: 'none' or opacity to hide or fade a layer.
The boundary's own placement (position, inset, pointer-events: none) comes from the grid;
overriding it here breaks the layer's containment.
OptionalzExplicit stacking override, read by normalizeLayers off the grid-child element to sort the
layer list (higher sorts later = on top; omitted ⇒ declaration order). It is honored ONLY at the
grid-children level — the layer's actual dispatch slot always comes from the resulting order
index (via LayerOrderContext), never from this raw number, so paint order and event
order can never disagree.
The layer's content — VirtualDivs,
RangeRects, floats — hosted inside the layer's boundary div. Children stack by DOM order within the layer (law 1).