Chart Prompts

Restyle my chart in the "Bond Coupon" 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 engraved bond certificate from a harbor or municipal authority. Ivory paper, sepia ink, a pale green guilloche border, a burgundy ribbon banner and a strip of detachable coupons along the bottom. Formal, archival, trustworthy.

Colors (use these exact values):
- Paper: #F4EDDA, with a soft radial lift to #F8F3E4 near the center.
- Sepia ink for the headline, data line, baseline and big numerals: #3B2A1C.
- Brown ink for the subtitle, axis labels, coupon small print, frame hairline and perforations: #5A4030.
- Guilloche green for the border band, border rules, corner medallions and coupon inner frames: #9BBB98.
- Ribbon burgundy: #7A2B35 (gradient from #8E3743 at the top), tails #5E1F28, fold shadows #3E1219. Burgundy is also used for the rosette marker cores and the peak value label.
- Gridlines: #CDBF9E. Coupon strip backing: #EFE5CC.

Typography (Google Fonts):
- Cinzel 700 for the ribbon text: 21px, 3px letter-spacing, ivory on burgundy, naming the issuer or series. Cinzel 600 at 7.5px (1px letter-spacing) for "COUPON No. n" and Cinzel 400 at 6.5px for "DUE 1 JANUARY" on each coupon.
- Old Standard TT for everything else: headline 25px 700 sepia, centered, stating the finding; subtitle 15px italic brown with measure, unit and period; axis labels 14px; value labels 14px (the peak 18px 700 in burgundy); coupon years 18px 700; source 12px italic. Write rates with vulgar fractions (4½%, 3¼%, 8¾%) as a certificate would.

Layout:
- Border band between insets 14 and 40px: five interlaced sine lines (0.7px green, amplitude 9px, wavelength about 57px, phases 72 degrees apart) running around all four sides, framed by 1.6px green rules at insets 12 and 42, then a 0.6px brown hairline at inset 48.
- Corner medallions on the band at each corner: r 19 ivory disc with a 1.2px green ring and a small woven rosette (six phase-shifted rings, radius 12, 10 lobes, amplitude 4, 0.5px).
- Ribbon banner centered at the top (470 x 40 px at y 64) with a 0.6px pale gold (#E8D3A8) inner frame 5px in, tails 44px wide dropping 10px behind each end with a V notch, and small dark fold triangles where ribbon meets tail.
- Headline at y 148 and subtitle at y 172, centered. Plot from x 130 to 850, y 196 to 420.

Axes and grid:
- Horizontal gridlines at round values, 0.8px #CDBF9E; y labels right-aligned 14px left of the plot with a % sign. A 1.2px sepia baseline with 6px ticks at each coupon year.
- The x-axis is a perforated coupon strip 26px below the baseline: a #EFE5CC backing with a 0.6px brown outline, and one coupon per labeled period (84 x 58 px, ivory, 0.9px brown border, 0.6px green inner frame 3px in) centered on its tick, reading "COUPON No. n", the year, and "DUE 1 JANUARY". Between coupons, a perforation of round dots (1.6px, 4.5px apart) in brown running the full strip height.

Marks:
- Line chart: a stepped line, 2.4px sepia with mitered corners, holding each value until the next reset, with a 6% sepia fill beneath. At each reset a rosette marker: an ivory circle r 7.5 with a 1.1px sepia ring and three interlaced burgundy rings inside (radius 4.3, 6 lobes, 0.6px). Label each reset with its rate, above the marker when the rate rose and below it when it fell, so labels sit in the open side of the step.
- Bar chart: square-cornered bars in sepia at 88% opacity, 50% of the band width, each topped by a rosette marker centered on its top edge and a fractional value label above; the peak bar's label in burgundy 18px 700. Use the same coupon strip as the x-axis.

Avoid: modern sans-serif type, saturated colors, rounded bars, drop shadows beyond the ribbon's fold, decimal rates where a fraction reads naturally, and more than one accent (burgundy) on the data.

When you're done, render the chart and check that every coupon is centered on its tick, the perforations sit exactly midway between coupons, no rate label touches the line, and the ribbon tails sit behind the banner.