Chart Prompts

Restyle my chart in the "Endowment Payout" 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 exhibit in a report to a foundation's trustees. Sober, precise and old-fashioned in the good way: white paper, a classic book serif title over a thin double rule, two disciplined colors and a scholarly margin note.

Colors (use these exact values):
- Page: #FFFFFF (paper white).
- Primary series: #1F4D3A (dark green). Secondary series: #B7862F (gold). Each panel's axis labels and title are in its series color, so each axis is keyed to its series.
- Shaded periods (downturns, recessions, bad years): #EDEDEB.
- Ink #1E1E1C for the title and double rule; secondary text #6B6A66; gridlines and the margin-note divider #DCDCD8.

Typography (Google Fonts):
- Libre Caslon Text: title 400 27px ink in sentence case stating the finding; the margin note heading in italic 17px; the footer exhibit number in italic 12px.
- Source Sans 3 for everything else: eyebrow 600 11px uppercase with 2.4px letter-spacing in #6B6A66; subtitle 400 15px #6B6A66 naming the organization, measures, unit and period; axis labels 600 12px in the series color; panel titles 700 10px uppercase with 1.4px letter-spacing above each panel at the 64px margin; direct labels 700 13px; margin note body 13px #6B6A66 on 19px lines; key text 12px.

Layout:
- 64px side margins. Eyebrow at y 50, title baseline at 94, then a double rule: 1px ink at y 110 and 0.6px ink at y 114, full width. Subtitle at y 140.
- Plot area from x 104 to 680, split into two stacked panels on one shared year axis: the primary panel from y 196 to 356 and the secondary panel from y 404 to 508, with about 48px of clear space between them holding the lower panel's title. Each panel has its own axis labels right-aligned 10px left of the plot; never a right-hand second axis.
- A margin column from x 754 to the right margin, separated by a 1px #DCDCD8 vertical rule: an italic heading ("The 5% rule"), a short explanatory note of five or six lines, then a key (line swatches and the shaded-period swatch) that stays inside the right margin.
- Footer: a 1px #DCDCD8 rule at y 552, "Source: ..." left and an italic "Exhibit 3" right.

Axes and grid:
- Each panel starts at zero with its own round ticks (for example 0 to 400 in the endowment panel, 0 to 20 in the payout panel, with a little headroom above the top tick). Label only the top tick with its unit ($400M, $20M). Never scale one measure against the other: two lines on one plot with different axes imply a fixed ratio that isn't there.
- Gridlines 0.8px #DCDCD8; a 1px ink zero line in each panel; 5px ink ticks below the lower panel every four years plus the last year, labeled in 12px #6B6A66.
- Shade whole year slots in #EDEDEB, the full height of both panels, behind everything, and tag the most important shaded period with a tiny 10px 700 label at the top.

Marks:
- Line chart: the primary series as a 2.75px #1F4D3A line with straight segments and round joins, points at mid-year, a 4px dot on the last point with a direct label above it ("Endowment $404M"). The secondary series in the lower panel as a 2.5px #B7862F stepped line that holds flat across each year slot (like a policy amount set once a year), labeled at its end and at its start.
- Bar chart: slender square-cornered #1F4D3A bars (about 55% of the slot) on the left axis, with the secondary measure as the stepped #B7862F line in its own lower panel; the same #EDEDEB shaded slots behind.

Labels and annotation:
- Explain the rule or method behind the numbers in the margin note, in plain prose, not on the chart itself.

Avoid: bright colors, gradients, markers on every point, a boxed legend inside the plot, rounded bars and decorative icons.

When you're done, render the chart and check that the title's claim is arithmetically true, both panels start at zero with clear space between them, the stepped line has flat treads for each period, and the title fits inside the margins.