Viewport <#document> at (0,0) content-size 800x600 children: not-inline
  BlockContainer <html> at (0,0) content-size 800x154 [BFC] children: not-inline
    BlockContainer <body> at (8,8) content-size 784x138 children: not-inline
      BlockContainer <details> at (68,68) content-size 664x18 children: not-inline
        ListItemBox <summary> at (92,68) content-size 640x18 children: inline
          frag 0 from TextNode start: 0, length: 5, rect: [92,68 36.84375x18] baseline: 13.796875
              "hello"
          ListItemMarkerBox <(anonymous)> at (68,68.5) content-size 12x17 children: not-inline
          TextNode <#text>
        BlockContainer <slot> at (68,86) content-size 664x0 children: not-inline

ViewportPaintable (Viewport<#document>) [0,0 800x600]
  PaintableWithLines (BlockContainer<HTML>) [0,0 800x154]
    PaintableWithLines (BlockContainer<BODY>) [8,8 784x138]
      PaintableWithLines (BlockContainer<DETAILS>) [8,8 784x138]
        PaintableWithLines (ListItemBox<SUMMARY>) [92,68 640x18]
          MarkerPaintable (ListItemMarkerBox(anonymous)) [68,68.5 12x17]
          TextPaintable (TextNode<#text>)
        PaintableWithLines (BlockContainer<SLOT>) [68,86 664x0]
