Viewport <#document> at [0,0] [0+0+0 800 0+0+0] [0+0+0 600 0+0+0] [BFC] children: not-inline
  BlockContainer <html> at [0,0] [0+0+0 800 0+0+0] [0+0+0 200 0+0+0] [BFC] children: not-inline
    Box <body> at [0,0] flex-container(column) [0+0+0 400 0+0+400] [0+0+0 200 0+0+0] [FFC] children: not-inline
      ImageBox <img> at [0,0] flex-item [0+0+0 400 0+0+0] [0+0+0 200 0+0+0] children: not-inline

ViewportPaintable (Viewport<#document>) [0,0 800x600]
  PaintableWithLines (BlockContainer<HTML>) [0,0 800x200]
    PaintableBox (Box<BODY>) [0,0 400x200]
      ImagePaintable (ImageBox<IMG>) [0,0 400x200]

SC for Viewport<#document> [0,0 800x600] [children: 1] (z-index: auto)
 SC for BlockContainer<HTML> [0,0 800x200] [children: 0] (z-index: auto)
