Chart Prompts

Restyle my chart in the "Assay Marks" style described below. Keep my data, chart type, title meaning and units; change only the presentation. Use the charting library this project already uses (plain SVG if there is none). If the library can't express a detail, draw it in a custom layer instead of dropping it. Measurements assume a 960 x 600 chart; scale them proportionally.

Mood: an assay office register engraved on a silver plate. Quiet, exacting and precise: one dark gunmetal line, tiny engraved ticks and hallmark stamps punched into the metal as markers.

Colors (use these exact values):
- Page: #F4F4F2 (soft silver-white), with a very gentle diagonal sheen from #FAFAF9 at the top left to #E9E9E6 at the bottom right. A 0.8px #C9CBCC hairline frame inset 20px from the canvas edges.
- Ink and the data line: #2F343A (gunmetal). Secondary text and leader lines: #7C8289 (steel gray). Gridlines and rules: #C9CBCC.
- Stamp faces: #FBFBFA, outlined in gunmetal.

Typography (Google Fonts):
- Cormorant Garamond with lining figures (font-variant-numeric: lining-nums): title 600 38px gunmetal stating the finding; an italic 500 26px second line in steel gray finishing the thought; stamp letters 700 16px; the end value 700 20px.
- Karla for everything else: eyebrow 700 11px uppercase with 3px letter-spacing in steel gray; subtitle 14px steel gray (measure, unit, period); axis labels 12px (x labels 500 with 1px letter-spacing in gunmetal, y labels 400 in steel gray); annotations 12px, the first line 700 gunmetal, the second 400 steel gray; source 11px.

Layout:
- 56px left margin. Eyebrow at y 66, title at y 108, italic line at y 142, subtitle at y 170.
- An assay stamp block in the top right corner (188 x 104 at x 716, y 44): #FBFBFA fill, 1.2px gunmetal border with 3px radius and a second 0.5px border inset 4px, "ASSAY OFFICE" in Karla 700 10px with 3px letter-spacing, the invented office name in Cormorant Garamond 700 26px with 5px letter-spacing, a 0.5px rule, then a row of three miniature stamps (shield, rosette, cartouche with a lowercase date letter).
- Plot from x 104 to 890, y 208 to 488. A footer rule at y 546 with the source at the left and a stamp key ("Date-letter stamps mark every fifth year" beside three 7px miniatures) at the right.

Axes and grid:
- Gridlines 0.6px #C9CBCC dotted (1 on, 3 off). A thin 0.7px gunmetal y-axis line 8px left of the plot with 6px ticks and labels right-aligned 20px left of the plot.
- Engraved baseline 10px below the plot: a 0.8px gunmetal line with a 0.35px line 3px under it. Tick marks hang from the lower line: 4px and 0.5px for every year, 9px and 0.9px for every fifth year, which also gets a label 38px below the plot.

Marks:
- Line chart: a single 2.2px gunmetal line with straight segments and round joins. Every ordinary point is a tiny ring (r 2, #F4F4F2 fill, 1px gunmetal). Every fifth period gets a punched hallmark stamp (half-size 14px) centered on the point, cycling shield, rosette (8-lobed outline, r = s(0.86 + 0.14 cos 8t)) and cartouche (octagon with clipped corners). Each stamp is a #FBFBFA face, 1.3px gunmetal outline, a second 0.6px outline at 78% size, and a date letter in Cormorant Garamond 700 16px (uppercase for the first 25-year cycle, lowercase once a new cycle starts; the letter cycle skips J). A small white 0.6px blurred highlight offset 1px down and right gives the punched feel.
- Bar chart: slender square-cornered gunmetal bars (about 40% of the band) with the same engraved baseline and ticks; every fifth bar (or the highlighted ones) carries a hallmark stamp centered 20px above its top, and ordinary bars carry a 12px Karla value.
- Multiple series: keep gunmetal for the lead series and steel gray #7C8289 for others, each labeled at its end.

Labels and annotation:
- Label the peak to its right with "2008 peak" (Karla 700 12px) and the value underneath (12px steel gray). Label the low beneath the stamp with a 0.6px steel leader. Give the latest value in Cormorant 700 20px with a "% below peak" note above it.

Avoid: color, gradients on marks, drop shadows beyond the faint punch highlight, heavy gridlines, rounded plot boxes and any more than one line weight for the data.

When you're done, render the chart and check that the stamps are legible at thumbnail size, that their letters sit centered in each shape, that no annotation collides with a stamp or the line, and that the "below peak" percentage matches the data.