# ADR-0037 — The Horizon is the Himalaya (/docs/maintain/adr/ADR-0037-the-horizon-is-the-himalaya)

- **Status:** Approved
- **Date:** 2026-11-03
- **Deciders:** [@puncoz](https://github.com/puncoz)
- **Approved by:** [@puncoz](https://github.com/puncoz)
- **Approved on:** 2026-11-03
- **Supersedes:** [ADR-0030](./ADR-0030-the-horizon-rises-over-the-page-and-its-sky-comes-alive.mdx) decision 2
  (in part: the aurora and rim, the clouds' place, the star's place and the observatory's place) and decision 4
  (in part: the light theme's scene)
- **Superseded by:** —
- **Design documents:** [`../app-flow/himalayan-horizon.mdx`](../app-flow/himalayan-horizon.mdx), `DESIGN.md`

## Context [#context]

- The owner asked to see what the logo's mountains and flag could do in the Horizon, creatively. It depends
  on [ADR-0036](./ADR-0036-the-site-is-nepal-dev-verse.mdx), and can be approved or refused without touching it.
- Every page ends with the Horizon (ADR-0030): stars, an aurora on the rim of a bare curved planet, shooting
  stars, the star rising with the scroll, three cloud bands and an observatory. The closing line above it says
  *You've reached the horizon* (ADR-0033). Nothing in it is about Nepal.
- Three things in the logo and the flag already fit this site's language:
  - **The flag holds a moon above a sun.** The sidebar's Use is a sun and Maintain a moon, and each version line
    is a moon. The site's own marks are on the flag.
  - **The logo's red face reads as light.** Red on a peak's sunward side is what alpenglow looks like.
  - **The logo's circuit traces end in ringed nodes,** much like this site's planet marks.
- What the code does now, read from `horizon-sky.ts` and `site.css`: the scene is 170 to 260px tall, in layers on one
  1200 by 260 view with `xMidYMax slice`. At a very wide screen that crops the top of the view, and at 1920px it would
  cut off a flag at the summit. So the summit and flag can't simply be added to that layer.
- A still sketch was drawn outside the repository to check that it reads, in both themes and at phone width.

## Decision [#decision]

1. **The range stands on the planet's edge.** The curve stays, and three ranges rise from it, back to front: a far one
   in haze, a middle one and a near one with the summit at the centre and two shoulders, drawn from the logo's
   silhouette. It is still a planet seen from its edge, and its highest mountains are the ones the site is named for.
2. **The peaks rise out of a sea of cloud.** The three existing cloud bands keep their timing and move between the
   ranges, so the middle range wades through them and the near one stands in front. It is the view from above the
   clouds that anyone who has flown past these mountains knows.
3. **The light comes from the star.** It rises with the scroll as it does now, just right of the summit, so everything
   lit is lit from the right.
4. **Alpenglow: the logo's red is the star's light.** As the star rises, in step with the scroll, the red on the
   sunward faces of the summit and the second peak fades in from nothing to the logo's red. Scrolling back fades it
   out. Only its opacity changes.
5. **The flag is raised when you arrive.** When 40% of the footer is in view, the flag runs up its pole from the summit
   over about 1.2 seconds, once per page view, and then waves slowly.
   - **It is not tied to the scroll, because a flag left part-way up its pole means mourning.** It is either on its way
     up or at the top.
   - It is drawn from the logo's flag, in its own colours in both themes, and is never recoloured, cropped, or placed
     under text or cloud.
6. **The sky repeats the flag.** A thin, still crescent moon stands directly above the star, in the same order as the
   flag's emblems: moon over sun. Nothing points it out, and it is there for anyone who notices.
7. **Every entry is a light on the mountain.** The logo's traces climb the near rock, one per public entry, each ending
   in a ringed light in that entry's ecosystem colour, seeded from its slug so it stays in place. The mountain lights up
   as the community documents more. Today it has one light.
   - **The planet row is still the way in.** The scene stays `aria-hidden`. Hovering or focusing an entry's link in the
     row brightens its light, through CSS only.
   - The lights use a fixed set of spots on the rock. Past that number, the rest appear only in the planet row.
   - The invented private projects get no light.
8. **The aurora and the rim glow go.** Auroras are not a Himalayan sky, and with the alpenglow, the flag and the warm
   glow they would be one colour too many. The site's teal lives on in the traces. The stars, their twinkling and the
   shooting stars stay.
9. **The observatory moves** to the near range's left shoulder, its telescope turned toward the star.
10. **Light theme: the same scene at dawn.** The sky washes warm toward the ranges, the rock is the logo's navy, and the
    far ranges are pale blue. The red and the flag do not change.
11. **The summit and the flag are never cropped, at any width.** The near range has its own layer, anchored at the bottom
    centre and scaled to fit, while the far and middle ranges run wider and fall off the edges. The scene grows to fit
    them, and its height is settled by measuring at 320px, 390px, 860px, 1412px, 1920px and 2560px.
12. **The rules of motion hold** (ADR-0030 decision 3). Only transform and opacity animate, in CSS, with no library. The
    flag's wave is a new, slow loop in the Horizon's exception to *The One Orbit Rule*, and runs only while the footer is
    on screen. Under reduced motion, with no scripts, or with no scroll-driven animations: the star stands risen, the
    alpenglow is full, and the flag stands raised and still.
13. **The sun and moon in the sidebar become the flag's.** `track-switch.tsx`'s two icons take the flag's forms: a sun
    with twelve rays and a crescent moon. It is a small change, and it ties the two sides of every planet to the flag.
14. **Unchanged:** the closing line, *You've reached the horizon. The Verse goes on.*; the dusk edge; the planet row; the
    link row; every URL and Markdown surface. No dependency is added.

## Options considered [#options-considered]

| Concern | Option | Pros | Cons | Verdict |
|---|---|---|---|---|
| Scene | The range on the planet's edge, with cloud, alpenglow, flag and lights | Joins the logo to the space theme; grows with the community | The most work; more layers to keep light | Proposed |
| Scene | Only a ridge silhouette and a flag replacing the curve | Quick | Looks like a clip-art swap; nothing means anything | Rejected |
| Scene | The full logo artwork in the footer | Faithful | Reads as a sticker; its wordmark and outline fail on the dark ground (ADR-0036) | Rejected |
| Flag | Raised once on arrival | Marks reaching the end, and never rests part-way | A small script threshold beside `HorizonAwake` | Proposed |
| Flag | Raised in step with the scroll | No script, the same as the star | Can rest at half-mast, which means mourning | Rejected |
| Flag | Standing still, always | The simplest | Misses the one moment that makes the footer memorable | Rejected |
| Community | A light per entry on the rock | The picture grows as people join | A second mark for each entry to keep in step | Proposed |
| Community | A climber or trail that moves | Playful | A second moving focus, and it would tire on every page's end | Rejected |
| Aurora | Removed | Fewer colours and two fewer blurred layers | Drops something the owner approved in ADR-0030 | Proposed |
| Aurora | Kept, dimmed | Keeps ADR-0030 whole | Not a Himalayan sky; competes with the alpenglow | Rejected |
| Prayer flags along a ridge | Left out | Avoids using a sacred object as decoration | Loses a very Himalayan image; the owner may overrule it | Rejected |
| Closing line | Unchanged | Still true, and ADR-0033 was just settled | Says nothing of the summit | Proposed |
| Closing line | "You've reached the summit. The Verse goes on." | Fits the picture | Loses the word the footer is named for | Rejected |
| Share images | Unchanged here | ADR-0035's design stands, and this stays reviewable | Shared links don't show the range | Left for a later ADR |

## Consequences [#consequences]

**Positive**

- The end of every page becomes the site's signature, and only this site could have it: the flag's own emblems in the
  sky, its colour on the snow, the community's lights on the rock.
- The footer now shows the community grow, with no copy and no counter.

**Negative / accepted trade-offs**

- **The scene gets taller**, so every page's footer takes more room.
- With one entry, the light on the mountain looks modest until more arrive.
- More drawn geometry in every page's HTML, so it is checked with the Horizon's cost in mind: the blurred aurora and rim
  layers go, and the ranges are flat fills.
- A national flag carries meaning. It is drawn exactly and treated with care (decision 5), and the owner reviews the
  drawing before it ships.
- Peaks are drawn from the logo, not from any real view, so no peak is named or claimed.

## Content invariants [#content-invariants]

None is touched. The footer is not part of any Markdown surface. §6.1: the lights come only from public catalogue entries,
which are already on the page; the invented private projects are never drawn.

## Security considerations [#security-considerations]

None beyond this: this change touches no endpoint and no secret, and reads only public catalogue fields. The scene is
static inline SVG with no user input.

## Implementation notes [#implementation-notes]

- [x] `src/lib/horizon-sky.ts`, pure and tested: the three ranges, the snow and red faces, the flag's place, the moon, and
  the lights' fixed spots and seeded assignment.
- [x] `src/components/horizon-footer.tsx`: the layers, with `entries` passed to the scene. A `src/components/horizon-flag.tsx`
  drawn from the logo's flag paths. `src/components/horizon-awake.tsx`: the arrival threshold, setting `data-summit`.
- [x] `src/app/site.css`: the scene's height, the alpenglow on `--horizon`, the flag's raise and wave, the lights through
  `:has`, both themes, reduced motion. `src/components/docs/track-switch.tsx`: the two icons.
- [x] Tests (ADR-0007): every light stands on rock and no two collide; the same slug gets the same spot; more entries than
  spots draw no extra light; no private project is drawn; the summit and flag fit at every measured width; the scene
  renders with no entries; the flag stands raised without scripts. `HorizonAwake`'s threshold and the CSS are not
  unit-tested; checked in Chrome instead.
- [x] Looked at, in Chrome on localhost against `bunx next build`: both themes at the widths of decision 11; the flag raised
  once, and on a page short enough that the footer shows at load; reduced motion; a planet link lighting its node; the dusk
  edge over the docs sidebar; a temporary folder with several entries, removed afterwards.
- [x] Departures found while building, each smaller than the decision it serves:
  - the flag lives in `src/components/nepal-flag.tsx`, shared with the brand mark, not a `horizon-flag.tsx`, and is redrawn
    by hand because the logo's flag is 83 auto-traced paths;
  - arrival is measured on 40% of `.horizon-scene`, not of the footer, because the scene's top holds the flag;
  - a page whose summit already shows at load keeps the flag raised with no animation, measured on the 404 with 45% of
    the scene in view;
  - sixteen light spots; past them an entry has no light, though its link stays in the planet row;
  - the scene is `clamp(230px, 28vw, 360px)` tall;
  - the observatory stands on a flat top added to the left shoulder at x=395, in the rock's colour, because at x=372 it hung
    over the ridge and a 320px screen cut it in half;
  - the larger red face ends in a point rather than a flat foot.
- [x] Measured in Chrome against `bunx next build`: light and dark at about 1412px; light at 320px, 390px and 860px (in same-origin
  frames, because the window would not shrink), with no sideways scroll. The window also measured 2371px wide, where the scene
  is 360px tall. 1920px and 2560px were not looked at separately. The flag lowered, then raised, on reaching the footer. A
  focused planet link lit only its own node, with eight entries from temporary folders `content/zz-temp-a` to `g`, removed
  afterwards. The dusk edge took the docs sidebar. The reduced-motion rules were read from the built CSS rather than seen.

- [x] `bun run test`, `bun run types:check` and `bunx next build` pass; `bun run lint` is reported while it stays blocked.

## Docs to update on implementation [#docs-to-update-on-implementation]

- [x] [`../app-flow/himalayan-horizon.mdx`](../app-flow/himalayan-horizon.mdx): Current;
  [`../app-flow/living-horizon.mdx`](../app-flow/living-horizon.mdx) with its Archify views.
- [x] `DESIGN.md`: the Horizon footer, *The One Orbit Rule*, the track switch. `.impeccable/design.json`.
- [x] `AGENTS.md` §1 and §5, [`../architecture/system.mdx`](../architecture/system.mdx).
- [x] "Superseded by" in ADR-0030; [`./index.mdx`](./index.mdx).