Viewport <#document> at (0,0) content-size 800x600 children: not-inline BlockContainer at (0,0) content-size 800x56 [BFC] children: not-inline BlockContainer at (8,8) content-size 784x40 children: inline frag 0 from Box start: 0, length: 0, rect: [28,28 49.71875x0] baseline: 26 Box at (28,28) content-size 49.71875x0 flex-container(row) [FFC] children: not-inline BlockContainer <(anonymous)> at (28,17) content-size 49.71875x22 flex-item [BFC] children: inline frag 0 from TextNode start: 0, length: 5, rect: [28,17 49.71875x22] baseline: 17 "Hello" TextNode <#text> ViewportPaintable (Viewport<#document>) [0,0 800x600] PaintableWithLines (BlockContainer) [0,0 800x56] PaintableWithLines (BlockContainer) [8,8 784x40] PaintableBox (Box

.button) [8,8 89.71875x40] PaintableWithLines (BlockContainer(anonymous)) [28,17 49.71875x22] TextPaintable (TextNode<#text>)