The text reference render is not byte-identical after all: a declared rel or rest length is applied by the span and then again inside SetSize, so .width(rel(0.5)) draws its child at a quarter. Also replaces the example that measured one-pixel lines with what the tests now say, since a span short of room overlaps its fixed lengths rather than collapsing them. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>