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 24 0+0+0] [BFC] children: not-inline
    BlockContainer <body> at [8,8] [8+0+0 784 0+0+8] [8+0+0 0 0+0+8] children: not-inline
      Box <div.display_flex> at [8,8] floating flex-container(row) [0+0+0 23.609375 0+0+0] [0+0+0 16 0+0+0] [FFC] children: not-inline
        BlockContainer <div> at [8,8] flex-item [0+0+0 23.609375 0+0+0] [0+0+0 16 0+0+0] [BFC] children: not-inline
          BlockContainer <div> at [8,8] floating [0+0+0 23.609375 0+0+0] [0+0+0 16 0+0+0] [BFC] children: not-inline
            BlockContainer <span> at [8,8] floating [0+0+0 14.265625 0+0+0] [0+0+0 16 0+0+0] [BFC] children: inline
              frag 0 from TextNode start: 0, length: 1, rect: [8,8 14.265625x16] baseline: 12.796875
                  "A"
              TextNode <#text> (not painted)
            BlockContainer <span> at [22.265625,8] floating [0+0+0 9.34375 0+0+0] [0+0+0 16 0+0+0] [BFC] children: inline
              frag 0 from TextNode start: 0, length: 1, rect: [22.265625,8 9.34375x16] baseline: 12.796875
                  "B"
              TextNode <#text> (not painted)

ViewportPaintable (Viewport<#document>) [0,0 800x600]
  PaintableWithLines (BlockContainer<HTML>) [0,0 800x24]
    PaintableWithLines (BlockContainer<BODY>) [8,8 784x0]
      Paintable (Box<DIV>.display_flex) [8,8 23.609375x16]
        PaintableWithLines (BlockContainer<DIV>) [8,8 23.609375x16]
          PaintableWithLines (BlockContainer<DIV>) [8,8 23.609375x16]
            PaintableWithLines (BlockContainer<SPAN>) [8,8 14.265625x16]
            PaintableWithLines (BlockContainer<SPAN>) [22.265625,8 9.34375x16]

SC for Viewport<#document> [0,0 800x600] (z-index: auto)
 SC for BlockContainer<HTML> [0,0 800x24] (z-index: auto)
