# swarm-ui design guide

Scope: **swarm-ui only** (the swarm-level Preact app — not the per-hive
dashboard, which has its own older visual language). This doc is the
*why*: the principles behind how swarm-ui looks and behaves, and the
concrete rules that follow from them. It deliberately doesn't show what
things look like — that's `ComponentsPage` (`/components`), the living,
always-current demo of every primitive in `src/ui/`. Code can't go stale
the way a doc's screenshots can, so treat `ComponentsPage` as the source
of truth for appearance and this doc as the source of truth for intent.
Colour variables specifically are `docs/web-ui/css-vars.md`'s job, not
repeated here.

Distilled from the design-language discussion in issue #3444 — read that
thread for the full reasoning behind any rule below that needs more
context than fits here.

## Visual language

- **Basis: Material Design, the Material You generation** (Android's
  current design language) — but swarm-ui strays fairly far from its
  theming approach; base16/stylix (below) is the actual colour contract,
  not Material's dynamic-colour system.
- **Frosted / tinted glass** where it fits — translucency over flat
  panels, not a hard rule for every surface.
- **Playful use of the multiple accent colours**, without tipping into
  visual noise — the base16 palette has several accent slots
  (`--purple`, `--cyan`, `--pink`, …); use more than one where it adds
  distinction, not decoration for its own sake.
- **Whimsy** — small, delightful touches are welcome (the per-hive
  dashboard's home-page matrix-rain background, `packages/dashboard/src/
  home.js`, is the reference example — currently in the dashboard
  package, not swarm-ui itself, but the pattern it sets applies here
  too). Whimsy still has to clear the accessibility bar below (motion,
  in particular).
- **Efficient navigation** — minimize clicks/hops for a common task.
- **Avoid junk drawers.** A control belongs next to the thing it
  affects, not tucked into a catch-all menu. Concrete anti-example (not
  swarm-ui, but the standard to avoid): the per-hive agent terminal's
  model selector living in a three-dot overflow menu instead of next to
  the thing that shows the current model.

## Motion

**General rule, not case-by-case: every non-essential CSS animation
gates on `prefers-reduced-motion` and pauses when its tab/section is
hidden.** The dashboard's matrix-rain background (`packages/dashboard/
src/home.js`/`.css`) is the existing reference implementation of this
pattern — genuinely does both today, confirmed by reading it — even
though it lives in the dashboard package rather than swarm-ui; every
future swarm-ui animation follows the same pattern, not just whimsy
pieces.

An in-app override (independent of the OS-level media query, for
someone who wants motion on despite a system-wide reduced-motion
setting, or vice versa) is tracked separately — see #3456, which needs
the client-settings surface from #3453 first.

Prefer CSS-driven animation over JS-driven where possible, and avoid
jarring content swaps (layout shift, hard cuts) where a transition can
smooth them instead.

## Theming

The mechanical contract (base16 slots, semantic vars, what a page's CSS
is and isn't allowed to reference) lives in `docs/web-ui/css-vars.md` —
read that for the how. This section is the *policy* layered on top:

- **User-theming compatible by construction.** The whole point of the
  base16/`colors.css` swap contract is that a user's own theme (stylix
  today) takes over with zero swarm-ui code changes — a generator
  replaces exactly one file. Don't build anything that assumes a
  specific palette's exact colours (contrast ratios, "this accent is
  always purple") beyond what the semantic var names promise.
- **stylix wins outright when it's active, no in-between state.**
  `nix/host-modules/hive-c0re/theme.nix` decides at *build time* whether
  a hive is stylix-themed; when it is, that palette is authoritative —
  swarm-ui's own light/dark logic (below) doesn't run at all rather than
  trying to negotiate with it. This is a deliberate simplification, not
  a limitation to fix: a stylix-using operator has already made their
  choice.
- **Light theme is accessibility, not a cosmetic extra** — confirmed
  position on #3444/#3452: some people need light for contrast/low-vision
  reasons, others need dark for photosensitivity, so "OS preference by
  default + explicit override" is the right shape, same as motion above.
  **Not shipped yet** — tracked as #3452 (light palette itself), #3453
  (the client-settings surface an override setting needs), #3454 (the
  override setting). Until #3452 lands, swarm-ui is dark-only.

## Data freshness & refresh

The governing question for anything that shows time-sensitive data:
**would a user returning to this tab expect current data?** If yes, it
needs a refresh story; a value that's silently gone stale with no way to
tell is worse than one that's visibly stale.

- **Relative-time labels must actually tick.** A `StatusChip`-style
  "fresh (5s ago)" computed once at fetch and never updated again reads
  as current when it isn't. Tracked as #3445 (`RelativeTime` component:
  takes a UTC datetime, not a precomputed age, and re-renders itself on
  an internal interval; pauses while its tab is hidden).
- **Pages that poll get a refresh-interval control, not silent
  staleness and not push.** SSE/WebSocket push was considered and
  rejected for now — "overkill, leads to the same mess we have in
  core." Instead: a small, Grafana-like "refresh every: off / 10s / 30s
  / 1m / …" control the operator sets per page, paused while the tab is
  backgrounded and resumed on foreground. Tracked as #3446
  (`OverviewPage`'s hive-status roster is the first real caller).
- **A refresh must never clobber input the operator is mid-edit on.**
  Any future polling component's contract needs to make this the
  caller's problem to opt out of correctly, not something the next
  adopter discovers by shipping a bug.

## Errors

**`ApiErrorPanel` + the RFC 9457 `ProblemDetails` shape it renders is
the canonical error surface** for every API failure in swarm-ui, not
just its original callers — nobody should build a softer/quieter error
UI later. Concretely: full untruncated `detail`, a copy button, no
"something went wrong, try reloading."

This follows from **power-user-first**, one of the standing principles:
swarm-ui instances are mostly self-hosted and operators are techies, so
errors should give them what they need to actually diagnose a problem
rather than a friendly wall. Power-user-first doesn't mean
newcomer-hostile — the UI should still be self-explanatory, warn or ask
for confirmation before a destructive/dangerous action, and offer
helpful hints — it just shouldn't get in the way of someone who already
knows what they're doing.

## Empty states

Graceful fallbacks, always — a table with zero rows should show
something that represents "no rows" (a real empty-state message), not
just bare column headers floating over nothing.

## Layout & viewport

- **swarm-ui adapts to screen size and fully supports touch** — this is
  not a desktop-only app. Concrete floor: every interactive control from
  the shared `ui/` kit (buttons, inputs, selects) carries a minimum
  touch target (`2.75em` ≈ 44px, WCAG 2.5.5) by default, so this isn't
  something each page has to remember. Tracked follow-through:
  #3447 (page-level layout — nav wrap, no fixed-width assumptions).
- **Phone is a second-class citizen for now, not an unsupported one.**
  Things must not *break* at phone width, but don't over-invest in phone
  optimization beyond that yet. A PWA manifest (installable, basic
  status-check/interaction use case) is wanted eventually but is its own
  future slice, not implied by "supports touch" today.
- **A narrow viewport isn't only a phone** — a tiling-window-manager
  user with swarm-ui in a narrow tile hits the same layout constraints a
  phone does. Design for the constraint (narrow viewport), not the
  device.

## Component-first design

When something needs a table, a form field, a button — build (or adopt)
a `src/ui/` primitive that enforces consistent theming and behaviour,
rather than styling it inline on the page that happens to need it first.
`Panel`/`StatusChip`/`Table`/`TextField`/`SelectField`/`Button` are the
primitives that exist as of this writing, each with its own
`/components` demo; `/components` always has the current, complete list
— this doc won't try to keep a duplicate inventory in sync.

Default heuristic for *when* to promote page-scoped styling into a
shared primitive: the day a second real page needs the same thing, not
speculatively ahead of one. (Exception: when a peer explicitly asks for
a primitive ahead of a second caller, as happened with the form kit —
that's a judgement call each time, not a rule change.)

**Every new `ui/` component gets a demo section on `/components` the
same day it lands** — no primitive without a place to see it. One
deliberate exception exists today: `FormField`, the internal label+
control wrapper `TextField`/`SelectField` share, isn't itself a
primitive a page reaches for directly, so it has no demo of its own —
that's a real, considered exception (see its own doc comment), not an
oversight this rule missed.

## Attention

"Attention-optimized" here means the system should lead the operator's
attention to where it actually matters (an error, a state change worth
noticing) — not attention-optimized in the engagement/growth sense of
maximizing time-on-page.

## Open questions

Tracked separately rather than asserted here as settled:

| Question | Tracked in |
| --- | --- |
| Light theme (palette + `prefers-color-scheme` default) | #3452 |
| Client-local settings surface (page + storage) | #3453 |
| Theme override setting | #3454 |
| Reduced-motion override setting | #3456 |
| PWA manifest / installable phone experience | not yet filed — mentioned in #3444, no concrete scope agreed |