Viewport <#document> at [0,0] [0+0+0 800 0+0+0] [0+0+0 600 0+0+0] children: not-inline
  BlockContainer <html> at [1,1] [0+1+0 798 0+1+0] [0+1+0 42 0+1+0] [BFC] children: not-inline
    BlockContainer <body> at [10,10] [8+1+0 780 0+1+8] [8+1+0 24 0+1+8] children: not-inline
      BlockContainer <div.first> at [11,11] [0+1+0 778 0+1+0] [0+1+0 22 0+1+0] children: inline
        frag 0 from Box start: 0, length: 0, rect: [22,22 0x0] baseline: 22
        Box <span.second> at [22,22] flex-container(row) [0+1+10 0 10+1+0] [0+1+10 0 10+1+0] [FFC] children: not-inline
          BlockContainer <(anonymous)> at [22,22] [0+0+0 0 0+0+0] [0+0+0 0 0+0+0] [BFC] children: inline
            TextNode <#text> (not painted)

ViewportPaintable (Viewport<#document>) [0,0 800x600]
  PaintableWithLines (BlockContainer<HTML>) [0,0 800x44]
    PaintableWithLines (BlockContainer<BODY>) [9,9 782x26]
      PaintableWithLines (BlockContainer<DIV>.first) [10,10 780x24]
        PaintableBox (Box<SPAN>.second) [11,11 22x22]
          PaintableWithLines (BlockContainer(anonymous)) [22,22 0x0]

SC for Viewport<#document> [0,0 800x600] [children: 1] (z-index: auto)
 SC for BlockContainer<HTML> [1,1 798x42] [children: 0] (z-index: auto)
