MONTGOLFIER — how it was made

Concept

MONTGOLFIER is a fictional dawn-flight instrument for the armchair balloonist — anyone who has watched an envelope rise over a valley and wondered how it is aimed. It is not a page about ballooning; it is a short flight. You lift from Foldgate Meadow at 05:52 with 210 seconds of propane, read five winds stacked overhead like shelves, and set down — feather-soft or graceless — in a named field, logged in a pilot's book that remembers how many times you have flown.

Palette — dawn, from night to day

#1F2438 · pre-dawn

Top of the sky at 05:52. The whole gradient migrates out of this over the flight.

#F4C89A · dawn apricot

First warm light on the horizon; the brand's signal colour for eyebrows and the active wind.

#9CC4D8 · day blue

Where the sky is going. It arrives only if you stay up long enough to see it.

#B3342B · balloon red

The envelope's live gores, the burner, every urgent readout. One red, used sparingly.

#E8DCC8 · cream

The balloon's alternate gores and the header text — soft against the dark sky.

#F1E7D4 · paper

Instruments and logbook: warm cartridge paper, so the readouts feel drawn, not lit.

The palette is argued from the subject, not chosen for taste: the sky is the clock. Rather than a static scheme, three four-stop skies (night, dawn, day) are interpolated by a single day-progress value, so the colour you see is literally the time of the flight.

Type

Fraunces — the wordmark, the huge Lighter than air, every instrument value and the logbook prose. Its optical sizing goes soft and old-almanac at display sizes and crisp at caption sizes; the italic carries the romance the subject asks for.
Source Sans 3 — labels, hints, how-to, this paragraph. A calm, legible grotesque that steps back so the numbers and the sky do the talking. Instrument values use tabular-nums so the readouts never jitter as they count.

Techniques

The signature is altitude-as-steering. Five wind bands are stacked from the valley floor to 2,400 m, each with its own speed and direction — east, then a west return flow, a fast eastbound morning stream, a hard western shear, and the roof rivers. A smoothstep blends one band into the next so there are no hard edges, and the wind column on the right renders the whole stack live: animated glyph flow at each band's true speed, a tick scale, and a marker showing exactly where you are. There is no left/right control anywhere on the page. To go somewhere, you climb or vent into the layer that is already going there — which is precisely how real ballooning works.

Underneath, buoyancy is real-ish: the burner adds heat, heat decays toward ambient, and lift is the gap between envelope temperature and the neutral temperature for your altitude, damped by vertical velocity. Everything else is drawn in one canvas 2D context — a value-noise terrain sampled per-column for hills, rivers (carved where the noise dips below sea level) and field patchwork; parallax ridge layers hazed toward the horizon; villages whose windows light at dawn and whose chimneys trail smoke on the valley breeze; a nine-gore balloon with clipped meridians, a directional sun-shadow, a live flame and a deflation collapse on landing. No libraries, no images — the brief's showcase rule, kept honestly.

Iteration log

Pass 1 · Craft

Read the rendered instruments against the physics. Propane had no urgency until it hit zero, so the fuel bar and its % readout now bloom red under 25% — the same moment the flight hint says "start thinking about a field", so colour and copy land together. Verified body and instrument contrast on paper (#2B2320 on #F1E7D4) sits well past 4.5:1, and confirmed every readout uses tabular figures so the panel doesn't twitch.

Pass 2 · Depth

Two additions for the second read. A soft burner "breathe" — while you sit on the meadow before lift-off, the BURN control pulses a warm ring, so the one thing you must do is legible without reading the hint. And a rare pre-dawn meteor: while the stars still hold, once in a long while a streak crosses the upper sky with a fading tail — most flights never see it, which is the point. Both are gated so they cost nothing when they aren't happening.

Pass 3 · Hardening

Headless QA at 375, 768 and 1440: no horizontal overflow, hero and panel visible, zero console errors. The reduced-motion path renders a settled mid-flight dawn frame — aloft over the Vale, no rAF — and disables cast-off; the rAF loop and day-clock both suspend on document.hidden; DPR is capped at 2 and the scene re-lays on resize. Chanel rule: removed the constant sub-degree balloon sway — the wind-driven basket tilt already gives the envelope life, and the extra oscillation was ornament no one could see.

Honest notes

Flight feel is tuned for a two-to-four-minute dawn hop, not a simulator — the buoyancy constants are chosen for readable, forgiving flight rather than strict physics. The logbook entry count persists in localStorage; clearing site data resets it to Entry Nº 1. The meteor is deliberately rare, so a quick look may not catch it — that is by design.