Tail layer at fixed px width (was stretching to 100% — x misalign); head at top:0 with cy=24; date rows render active rails so pills sit beside an unbroken graph; 5px card gaps; mobile keeps vertical card padding so alignment holds. tools/timeline-verify.js is the browser geometric lint: 0 violations on all three demo repos at 1280 and 375. check-in: 994815316c user: dmestas tags: trunk