continue. FIX ROUND 10, one item: make the shading NOTICEABLE on the parts where it is still faint. Design decided, just implement. Keep your reasoning short and in plain sentences; if your thoughts turn into symbols or repeats, stop thinking and edit. Stop at about 40 tool calls and wait for 'continue'.

Three independent reviewers checked your round-9 render. Verdict: the ports are fixed (no tooth at either mouth, continuous passages), the chamber is fixed (valve faces flush with the roof, no gas notch beside or between the valves, plug embedded with its electrode, spark and flame stay inside, dots still on the heads, cam timing and poppet valves hold, no colour shift), and shading is clearly visible on the piston, crank disc, valve stems, plug and rollers. ONE miss: the large grey head-casting band (engine x 770-1030, y 256-362) has a gradient of only a few grey levels (headGrad runs #A9B4BF to #7C8794 over the WHOLE 136 px block including the hatch bands, so the visible band gets a sliver of it), and the hatch bands, the teal water jackets, the crankcase tubes, the outer crank disc and the dark crank ring are still flat. The owner asked for noticeable shading on all parts, flat-colour style kept.

DO THIS (index.html defs and fills; keep every outline, tint and hue rule; no blue, yellow, orange or red on metal):
 1. headGrad: change to gradientUnits="userSpaceOnUse" x1=0 y1=256 x2=0 y2=362 so the visible casting band spans the WHOLE range, with stops 0 #CBD5DF, 0.5 #98A3AE, 1 #5F6A77 (about a 35 percent lightness range). Make sure every element that uses headGrad still shows correctly (the band is a rect y 240-376; the hatch bands drawn over it keep their pattern).
 2. Add a 2 px highlight line along the top edge of the casting band (y 256-258, fill #E3EAF0, opacity 0.55) and a 2 px shadow line along its bottom edge (y 360-362, fill #3E4753, opacity 0.5), x 768-1032, drawn before the valve train and the plug so nothing is covered.
 3. Crankcase tubes (the two rects x 780-820 and 980-1020, y 376-694): horizontal cylindrical gradient, edges #7F8996, centre #BAC4CE (new def tubeGrad, userSpaceOnUse per tube or two defs).
 4. Outer crank disc (the r=160 circle) and the pan: radial turned-metal like crankGrad but centred up-left: centre #B5C0CB, mid #8E99A6, rim #66707C.
 5. Dark crank ring / flywheel (the #2B3038 dimmed disc and ring, and the counterweight): radial or linear from #3C444E to #1E232A so they read as shaded dark metal (keep their light outline).
 6. Water jackets (teal #4C6A73 bands): left-to-right gradient, #5F8190 to #3B555D (still teal, not a gas colour).
 7. Cam towers and bearing rings: the same vertical light-to-dark as the new headGrad (use headGrad with userSpaceOnUse is fine only if it looks right; otherwise a copy towerGrad y 204-240).
 Extend the outline CSS rule to any new fill so outlines stay.

CHECK: (a) node measure_engine.mjs --times 5.5,7.33,8,11.5,16,21.5,24,27.5,31 --shots workspace/meas10 : all checks pass. (b) A NUMBER, not a vision look: from the live-page screenshot of the tool (or a new headless screenshot of the edited page at t=6), print the mean grey of the casting band at engine px (800, 262) and (800, 356): their difference must be at least 35 levels (0-255), and the same kind of top-to-bottom or left-to-right difference of at least 25 levels on a crankcase tube cross-section, on the outer crank disc (upper-left versus lower-right of its visible rim) and on a water jacket. Print the numbers in your report. (c) Then ONE look at a 4x head crop from that screenshot: shading visible at 1x, no banding, no coloured metal.
THEN: BEFORE rendering back up the round-9 renders: final.mp4 -> final_v9.mp4 and review.mp4 -> review_v9.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 10 to REVIEW.md, REPORT.md, NOTES.md. Final report: done or not done with the numbers, the gate, files written, anything imperfect. Two reviewer remarks to list in REPORT.md as accepted, not fixed: the gas crossfade from red to blue passes through purple for a few frames around t=15.9 (a blend between the two phases; you did not change it), and the spark glow is a hard-edged pale disc (as before).