Viewport <#document> at (0,0) content-size 800x600 children: not-inline
  BlockContainer <html> at (0,0) content-size 800x66 [BFC] children: not-inline
    BlockContainer <body> at (8,8) content-size 784x50 children: inline
      line 0 width: 89.71875, height: 50, bottom: 50, baseline: 16.921875
        frag 0 from Box start: 0, length: 0, rect: [28,38 49.71875x0]
      Box <div.button> at (28,38) content-size 49.71875x0 flex-container(row) [FFC] children: not-inline
        BlockContainer <(anonymous)> at (28,27.078125) content-size 49.71875x21.84375 flex-item [BFC] children: inline
          line 0 width: 49.71875, height: 21.84375, bottom: 21.84375, baseline: 16.921875
            frag 0 from TextNode start: 0, length: 5, rect: [28,27.078125 49.71875x21.84375]
              "Hello"
          TextNode <#text>

ViewportPaintable (Viewport<#document>) [0,0 800x600]
  PaintableWithLines (BlockContainer<HTML>) [0,0 800x66]
    PaintableWithLines (BlockContainer<BODY>) [8,8 784x50]
      PaintableBox (Box<DIV>.button) [8,18 89.71875x40]
        PaintableWithLines (BlockContainer(anonymous)) [28,27.078125 49.71875x21.84375]
          TextPaintable (TextNode<#text>)
