The previous pass approximated the reference with utility guesses
(rounded-2xl, p-4, shadow-xl, dark ring). The actual spec is a hairline
border ring composed with a soft 0 8px 24px drop shadow, 10px radius,
12x14 padding, and an 80ms left/top glide. Tailwind shadow utilities
can't compose a ring with a custom drop shadow, so the surface moves
into the design system as .chart-tooltip (theme-aware: dark swaps the
ring to alpha-white and lets it carry the edge).
Money/numeric figures also pick up the reference's mono treatment:
font-mono + tabular-nums on every value across time-series, sankey,
and goal-projection, so digits don't jitter while the scrubber moves.
One visual contract for all three D3 tooltip surfaces, matching the
design reference: p-4, rounded-2xl, shadow-xl, no edge ring in light
mode. Dark mode keeps a 1px alpha-white ring since a shadow alone
disappears against dark surfaces.
- goal_projection_chart_controller drops its hand-copied class string
(it still carried the old bordered recipe — the drift this util
exists to prevent) and builds its two lines through the shared
factory: secondary date line, tabular value line.
- New content conventions exported alongside the container contract:
context line = text-xs text-secondary, values = font-medium
tabular-nums. Time-series and sankey adopt them.
- Sankey node titles now escape before .html(); user-named categories
were previously interpolated raw into the tooltip markup.
Closes#2011.
time-series and sankey each created their cursor-following tooltip with a
duplicated className literal that had already drifted apart: time-series was
missing `text-primary` and `z-50`. Move the visual contract into
app/javascript/utils/chart_tooltip.js as CHART_TOOLTIP_CLASSES and have both
controllers reference it. Each keeps its own behavioural classes (time-series
its initial `opacity-0`; both `top-0`; sankey toggles opacity via inline
style). `privacy-sensitive` stays bundled so future copies can't drop it.
Also exports a createChartTooltip factory for the raw-DOM idiom.
goal_projection_chart_controller is not in main yet (it lands with the goals
work in #1798); it migrates to the same symbol there.
