Viewport <#document> at (0,0) content-size 800x600 children: not-inline
  BlockContainer <html> at (1,1) content-size 798x0 [BFC] children: not-inline
    BlockContainer <body> at (10,10) content-size 93.59375x19 positioned [BFC] children: not-inline
      BlockContainer <nav> at (11,11) content-size 91.59375x17 children: inline
        frag 0 from TextNode start: 0, length: 10, rect: [11,11 91.59375x17] baseline: 13.296875
            "border box"
        TextNode <#text>

ViewportPaintable (Viewport<#document>) [0,0 800x600]
  PaintableWithLines (BlockContainer<HTML>) [0,0 800x2]
    PaintableWithLines (BlockContainer<BODY>) [9,9 95.59375x21]
      PaintableWithLines (BlockContainer<NAV>) [10,10 93.59375x19]
        TextPaintable (TextNode<#text>)
