Chart Prompts

Restyle my chart in the "Circadian Rhythm" 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: a figure from a sleep laboratory paper. Clean white page, one confident navy trace, and a black and white light/dark bar under the plot like an actogram. Scientific, quiet and exact.

Colors (use these exact values):
- Page: #FFFFFF.
- Primary ink, the data line, titles and marker outlines: #22325A (dark navy).
- Darkness periods in the light/dark bar: #111111. Lights-on periods: #FFFFFF with a 1px #111111 outline.
- Night tint behind the plot during darkness: #F3F4F7.
- Gridlines: #D8DBE2. Secondary text: #6B7080.

Typography (Google Fonts):
- Lusitana 400 for the title, 34px, #22325A, sentence case, stating the finding.
- Cantarell for everything else: eyebrow 11px 700 uppercase with 2.4px letter-spacing in #6B7080 ("SLEEP LABORATORY · PARTICIPANT 07"); subtitle 15px 400 #6B7080 with measure, unit, sampling and period; axis labels 12px 400 #6B7080; marker labels 12px 700 navy with the value on a second line in 12px 400 #6B7080; day labels 11px 700 uppercase with 2px letter-spacing in navy; source 12px.

Layout:
- 56px left margin. Eyebrow at y 70, title at y 110, subtitle at y 138. Plot from x 96 to 900, y 176 to 440.
- The light/dark bar sits 22px under the plot, 14px tall, spanning the full x range. Time labels (12:00, 18:00, 00:00...) 20px under it, then day labels ("DAY 1", "DAY 2") centered on each calendar day 20px lower.
- Bottom row at y 565: a small key for the bar (16 x 9 swatches: "Lights on", "Lights off, 23:00 to 07:00") on the left, "Source: illustrative data" right-aligned.

Axes and grid:
- Horizontal gridlines only, 0.8px #D8DBE2, every 0.2 units. Y labels right-aligned 12px left of the plot, with the unit ("°C") in 700 above the top label. No axis lines.
- Small 5px tick marks under the plot every 6 hours in #6B7080.
- A dotted 0.8px navy reference line (2 on, 4 off, 60% opacity) at the overall mean, labeled "48 h mean 36.91 °C" in 11px #6B7080 at its left end.

Marks:
- Line chart: a single smooth monotone-cubic line, 2.6px #22325A, round joins and caps, no fill and no point markers. The daily minimum of each cycle gets an open circle (r 6, white fill, 1.8px navy stroke) with "Minimum 04:30" and the value centered below it. Shade darkness periods behind the plot in #F3F4F7.
- Bar chart: slim square-cornered navy #22325A bars (about 55% of the band) on white, with the lowest bar in each cycle drawn as an outlined bar (white fill, 1.8px navy stroke) and labeled underneath; keep the black and white light/dark bar under the category axis whenever the categories are times.

Labels and annotation:
- Compute the title's time and values from the data. Label only the extremes; everything else reads off the grid.

Avoid: colored series, gradients, drop shadows, point markers along the line, heavy axis lines and any second y axis.

When you're done, render the chart and check that the black segments of the light/dark bar line up exactly with the tinted night columns above, that the minimum circles sit on the true lowest samples, and that the marker labels do not touch the line or the bar.