continue. FIX ROUND 7, one small item, design already decided, just implement. Keep your reasoning short: one edit, run the measuring tool, look at two crops.

Three fresh independent reviewers checked your round-6 final.mp4 at 24 different times. Result: ALL 14 part pairs now read as separate parts (cam lobe | tower, roller | lobe, barrel | stem | head, spring | retainer, spring | casting, plug | background, piston | wall, rings and pin | piston, crank pin | disc, counterweight | flywheel, valve head | seat), no metal looks like a gas colour, and every earlier fix still holds (leaders, dial halo, last-frame caption, piston, springs, symmetry). Well done.

ONE weak spot all three found: the CONNECTING ROD where it lies over the light crank disc / web (visible at t=13, 18, 19.5, 21, 26, 28, 29 and others). Rod and disc are nearly the same steel grey and only a 1.5 px dark line separates them. Kavan's rule was: if parts are the same colour, tint one of them slightly. So:

THE FIX (index.html, rod group around lines 66-72): tint the rod family a step lighter than the crank and casting steel, using ONE flat colour #B4BEC9 (cool light grey; the valves are #C5CDD5, keep that different) on: rodPoly, rodBig, rodSmall. Keep their existing dark outline (stroke #0E1116, stroke-width 2) on all three; rodBig and rodSmall currently get their outline from the CSS rule keyed on fill="url(#steelGrad)", so after you change their fill you must add them (by id) to that outline rule, or give them stroke attributes directly. Do not change the crank disc, crank pin disc, counterweight, piston or anything else. No blue, yellow, orange or red hue on the rod.

CHECK: node measure_engine.mjs --times 5.5,7.33,8,11.5,16,21.5,24,27.5,31 --shots workspace/meas7 (all 17 must still pass). Then look (lower crop = crop=500:640:650:370 then scale 2x, from ffmpeg -ss T of the NEW final.mp4) at t=13, 19.5, 26 and 29: the rod must read as a lighter part than the crank disc where they overlap, with its outline still visible, and the rod must still look like one part with its big-end boss and small end.

THEN: BEFORE rendering back up the round-6 renders: final.mp4 -> final_v6.mp4 and review.mp4 -> review_v6.mp4 (do not overwrite older backups). Render review.mp4 and final.mp4; ffprobe gate (h264, 1 video stream, 1920x1080, 30/1, 32.0 s +/-0.05, no audio); append round 7 to REVIEW.md, REPORT.md, NOTES.md. Final report: done or not done with evidence, the gate, files written. Two things the reviewers noted that you should list in REPORT.md as accepted and not fixed: (a) the callout leader runs down the valve axis and covers the roller, spring and stem for the 2.2 s of each callout (this is the approved design), (b) the last coil of each spring ends in a small diagonal tick on the stem axis at the retainer (by design, it seats on the stem).