Optionalbackgroundfill color behind the content — unset = no fill (a transparent padded group)
Optionalborderborder stroke color — unset = no border
Optionalborderborder stroke width (mm) — default DEFAULT_BOX_BORDER_WIDTH; only used when borderColor is set
Optionalkeepnever split: not enough room = the whole box moves to the next page, and content taller than one full page throws KapomLayoutError — default false (split between children)
Optionalpaddinguniform inner padding (mm) — default DEFAULT_BOX_PADDING
Optionalradiuscorner radius (mm) for the fill/border — default 0 (square corners). A box that splits across pages rounds every segment's own corners (so a mid-break segment is rounded on all sides).
a painted container: fill/border/padding around a vertical stack of blocks. By default it splits across pages at child boundaries, "clone" style — each page's segment closes its own background/border + padding, then a fresh box continues at the top of the next page (a single text node never splits internally — it moves to the next segment whole, so a one-child box effectively keeps together automatically). Children that paginate themselves or force page-breaks (table/section) are rejected fail-fast at build time, same as RowNode.