Chart Prompts

Restyle my chart in the "Day-N Retention" 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 dark mobile product-analytics screen. Calm midnight canvas, jewel-toned cohort curves, and a floating card that reads like a hover tooltip.

Colors (use these exact values):
- Background: #0C1427 (midnight blue). Chips and cards: #121C33 with a #2A3A5E 1px border.
- Series ramp, oldest to newest: #BAE6FD (ice), #A78BFA (violet), #F472B6 (pink), #FB923C (orange). Keep this cool-to-warm order so time reads as temperature.
- Text #E8EEF9; secondary #8C9AB8; captions and axis labels #5D6B8A; gridlines #1D2945; key-day verticals #24345A.

Typography (Google Fonts):
- Urbanist for the title (700, 27px, -0.3px letter-spacing, stating the finding), the subtitle (500, 15px) and big card numbers (700, 20px).
- Azeret Mono for chips (11.5px 500), axis labels (11 to 11.5px), end labels (11.5px 600 in the series color), card captions (10.5px) and the source.

Layout:
- 40px margins. Title at y 58, subtitle at y 86 carrying the measure and the lift versus the oldest cohort.
- A cohort selector row at y 112: 30px-tall fully rounded chips; an inactive "All" chip (no fill, #1D2945 border), then one active chip per series with a 9px color dot and "May · 18.4K installs"-style text. A right-aligned range note on the same row.
- Plot from x 76 to 806, y 196 to 522; the space right of the plot holds direct end labels.

Axes and grid:
- Horizontal gridlines 1px #1D2945, dashed 2 4 except the solid zero line; percent labels right-aligned 12px left of the plot.
- Solid 1px #24345A verticals at the key days (D1, D7, D30), with those day labels in 600 #8C9AB8 and other ticks in 400 #5D6B8A. No axis lines.

Marks:
- Line chart: monotone-smoothed curves, 2.25px, the best series 3px with a soft glow (the same path at 6px, 35% opacity, Gaussian blur 5, filter region the full canvas). Hollow ring markers (r 4.5, 2px series stroke, background fill) at Day 1, Day 7 and Day 30 on every curve. End labels "Aug 13.4%" nudged apart by at least 17px.
- Floating card: 214 x 92, 12px radius, #121C33, drop shadow 0 10px 12px black at 45%, a 3px color bar at its left edge, a mono eyebrow in the series color ("BEST COHORT · AUG") and three stats (Day 1, Day 7, Day 30). Float it over empty space just above the best curve with no leader line: its stats span several points, so a leader to any one point would misattribute them. The color bar and eyebrow tie it to the series.
- Bar chart: grouped vertical bars per key day, one bar per cohort in the ramp colors, 4px top radius, with the same chips, card and mono labels; hollow rings sit on the bar tops.

Avoid: pure black, neon saturation beyond these values, legends detached from the data (the chips and end labels do that job), and a card that covers any curve.

When you're done, render the chart and check that the ramp order matches the cohort order, ring values and card numbers match the data, the stated lift equals the rounded values shown, and end labels do not overlap.