Viewport <#document> at (0,0) content-size 800x600 children: not-inline
BlockContainer at (0,0) content-size 800x200 [BFC] children: not-inline
Box at (0,0) content-size 400x200 flex-container(column) [FFC] children: not-inline
ImageBox ![]()
at (0,0) content-size 400x200 flex-item children: not-inline
ViewportPaintable (Viewport<#document>) [0,0 800x600]
PaintableWithLines (BlockContainer) [0,0 800x200]
PaintableBox (Box) [0,0 400x200]
ImagePaintable (ImageBox![]()
) [0,0 400x200]