Where the tradition has to yield.

Rules

• :focus-visible, not :focus. Mouse users do not get a ring on click; keyboard users always do.
• Never outline: none without an equivalent replacement in the same declaration.
• Focus is never colour alone. A border colour change is not a focus indicator — it fails for anyone who cannot see the difference.
• Focus order follows reading order. If it does not, the DOM is wrong; do not repair it with tabindex values above zero.
• Focus is restored after any overlay closes, to the element that opened it.

Implementation

The stylesheet collapses all durations under the media query, and the generator checks the same query in JavaScript before running its draw-on. Two mechanisms because the animation is not purely declarative — and a CSS-only guard would leave the JS path running.

@media (prefers-reduced-motion: reduce) {
  * { transition-duration: .001ms !important;
      animation-duration:  .001ms !important; }
}

Limits

• Nothing loops indefinitely except an explicit loading indicator, which stops when loading stops.
• No parallax, no auto-play, no motion tied to scroll position.
• Nothing flashes more than three times per second — the draw-on staggers segments but never blinks.
• Duration ceiling of 600ms for anything a user is waiting on.

Hard limits

• Density ≤ 10% of any viewport at any breakpoint. Kolam belongs to empty states, onboarding, brand moments and print — never behind body text, never in table chrome, never as a persistent page ground at full strength.
• Never the sole carrier of meaning. A motif may reinforce a state; it may not encode one. Every state needs text plus a non-pattern cue.
• 3:1 for line art. Kolam strokes are non-text graphics. At --kambi-1 on a busy ground they will not clear it — raise the weight or lower the density.
• Always aria-hidden when decorative, which is nearly always. A generated pattern has no informational content to announce.
• Never behind text without a solid surface between them. Not at reduced opacity, not blurred.

What this system requires

• Name the source. Tamil terminology is used with glosses throughout, never as exotic labelling. The README credits kolam practice and the formal-grammar research — Gift Siromoney and colleagues at Madras Christian College, from the 1970s — that established kolams as a generable picture language and made this engine possible. The rationale for choosing this tradition at all, its contested chronology, and the threshold traditions elsewhere that arrived at the same constraints are set out in 01 · Origins.
• Avoid the sacred set. Some kolams are tied to specific festivals, to mourning, and to temple thresholds. The generator produces secular looped patterns only, and a denylist of ritual configurations ships alongside it.
• Assess fit before adoption. This language carries meaning. For a product with no relationship to that context it risks reading as ornament borrowed for texture. Say so in your own README rather than letting your users be the ones who point it out.
• Route credit and, where there is revenue, resources back toward the practice and the communities that sustain it. Kolam is authored by generations of women and is largely uncredited; an open-source system built on it should not repeat that.

What this system does not claim

• Not authoritative. This is one reading of the form by a design system, not a documentation of the tradition. Regional practice varies enormously and this engine captures a narrow slice.
• Not complete. The tile decomposition covers square kolams. Diamond grids, padi kolams, freehand rangoli and coloured-powder forms are outside it.
• Not a substitute for consultation. If you are shipping this to an audience for whom kolam is a living daily practice, ask them. The engine will not tell you what is appropriate on a given morning.

Automated — runs in CI

• Recompute every published contrast figure from the palette; fail on drift.
• axe-core on every documented component in both themes and all three densities.
• Assert no outline: none without a replacement in the same rule.
• Assert every interactive element resolves to ≥ 24px of its own geometry at P = 6, and ≥ 44px once the target expander is counted. Assert the expander is present on every control below --alavu-md.
• Assert generated kolams have zero open endpoints.
• Lint for length literals outside tokens.css.

Manual — every release

• Keyboard-only pass through every flow: reachable, visible, escapable, focus restored.
• Screen reader pass on forms, tabs and modals — VoiceOver and NVDA at minimum.
• 200% zoom and 400% reflow with no horizontal page scroll.
• Reduced-motion pass: confirm removal, not shortening.
• Greyscale pass: does every status still read?
• Pattern density screenshot at the smallest viewport.