Chart Prompts

Restyle my chart in the "Polar Night" 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 expedition almanac read by lamplight. Deep polar blue, one warm gold line glowing softly, a darker starlit band for the long night, and thin rules at the turning points of the year.

Colors (use these exact values):
- Page: #0C1628 (deep polar blue).
- Primary series: #F2C66D (pale gold), also for the eyebrow and key callouts.
- Secondary series: #7D93BD (faint twilight blue).
- Dark period band: #050B17, with stars in #FFFFFF.
- Ink: #E8ECF4. Secondary text: #8C99B3. Gridlines: #1C2A44.

Typography (Google Fonts):
- Montserrat Alternates throughout. Eyebrow 11.5px 600 uppercase with 2.6px letter-spacing in gold. Title 29px 600 #E8ECF4 stating the finding. Subtitle 14.5px 400 #8C99B3. Band name 14px 700 uppercase with 3px letter-spacing; band dates 12px #8C99B3. Tick labels 12px; month labels 11.5px 500 uppercase with 1.4px letter-spacing. Callouts 11.5px gold. Rule labels 11px ink at 80% opacity. Source 11.5px.

Layout:
- 56px left margin for text; plot from x 84 to 900 and about 320px tall. Title block at the top with a two-item legend right-aligned on the subtitle row.
- Label the shaded band inside itself near the bottom, centered; label vertical rules with short text beside them.

Axes and grid:
- Horizontal gridlines 0.8px #1C2A44 (1.2px at zero) with labels like "12h" right-aligned 12px left of the plot. No vertical grid; month names centered in each month with 5px ticks at month starts.
- Thin vertical rules for notable dates (solstices): 0.8px #E8ECF4 at 45% opacity, full plot height.

Marks:
- Line chart: the primary series as a 2.8px #F2C66D line with a soft glow (Gaussian blur stdDeviation 5 merged under the line, filter region covering the whole canvas), over a gold area fill fading from 12% to 2% opacity. The secondary series as a 1.6px #7D93BD dotted line (1 on, 4 off, round caps). Key points as 4px circles with page fill and a 1.8px gold stroke, labeled in gold on the open side of the curve.
- Bar chart: vertical bars in #F2C66D with 2px top corners and a faint glow, a second series as #7D93BD outlined bars; periods of darkness or zero values fall inside the #050B17 band.
- Dark band: a #050B17 rectangle over the zero period with about 70 tiny stars (radius 0.6, a few at 1.1) at 25 to 70% opacity scattered in its upper part.

Avoid: bright blues, multiple glows, heavy gridlines, clutter inside the dark band, and a second y axis.

When you're done, render the chart and check that the glow is not clipped, the band labels sit clear of the lines, gold callouts do not cross the dotted secondary line, and the title's day count matches the data.