Viewport <#document> at [0,0] [0+0+0 800 0+0+0] [0+0+0 600 0+0+0] children: not-inline BlockContainer at [0,0] [0+0+0 800 0+0+0] [0+0+0 16 0+0+0] [BFC] children: not-inline Box at [8,8] flex-container(column) [8+0+0 0 0+0+792] [8+0+0 0 0+0+8] [FFC] children: not-inline ViewportPaintable (Viewport<#document>) [0,0 800x600] PaintableWithLines (BlockContainer) [0,0 800x16] PaintableBox (Box) [8,8 0x0] SC for Viewport<#document> [0,0 800x600] [children: 1] (z-index: auto) SC for BlockContainer [0,0 800x16] [children: 0] (z-index: auto)