ui-ux-design-principles

# ui-ux-design-principles Canon for decisions about the USER's experience. The third of the design-principles trio: - `software-design-principles` – how a unit of code is written (SOLID, DRY, clean code). - `architectural-design-principles` – how the system is shaped (layers, twelve-factor, fitness functions). - **`ui-ux-design-principles`** – how the product looks, behaves, and is navigated, kept testable. The project's `design-guide.{md,json}` and `ia.md` are the per-project *instantiation* of this canon, the way `architecture.json` instantiates the layering rules. Markdown only, no scripts: consulted, not invoked. Like the architecture canon, it points each rule at how it's enforced (the E2E/Playwright layer, the design-adherence check against `design-guide.json`, a11y checks). A rule no test defends is advisory; one a check defends is part of the build. ## When to use - The `lakebase-sftdd-workflows` UX Designer imports it to author `design-guide.{md,json}` + `ia.md` and define the adherence gate. - The Driver imports it when building UI that must adhere to the design guide. - You're reviewing a user-facing change and need a shared vocabulary (heuristics, hierarchy, accessibility) rather than taste. - You're choosing how the UI is built and need the testability rules (framework choice, stable seams). ## UX review checklist (mandatory before promote/merge) Confirm each row before declaring the design done. A blank row is fine when scope justifies it; an unconsidered row is a smell. | Property | The rule | Enforced by | |---|---|---| | Feedback | Every data-changing action shows success AND failure feedback; no silent failures | E2E asserts the visible confirmation | | Accessibility | Keyboard-navigable, semantic HTML, sufficient contrast, labelled controls | a11y check (axe / equivalent) at the E2E layer | | Visual hierarchy | The primary action is most prominent; the eye is guided | design-adherence (tokens) + review | | Consistency | Reuses design-guide tokens + standard components; one pattern per job | design-adherence against `design-guide.json` | | Information architecture | Screens, navigation, primary flows defined before styling | `ia.md` present + E2E flows trace it | | Testable seams | Interactive elements expose stable selectors (`data-testid` / role) | E2E addresses elements by seam, not brittle CSS | | Loading / latency | Any action over ~200ms shows a loading state; feedback causes no layout shift | E2E + design-adherence | A property with no owner or no check: resolve it before merging. ## References - [Usability heuristics](references/usability-heuristics.md) – Nielsen's ten, condensed, each with its violation smell. - [Visual hierarchy](references/visual-hierarchy.md) – type scale, spacing, color, contrast, alignment: guiding the eye. - [Accessibility](references/accessibility.md) – WCAG essentials, semantic HTML, ARIA, keyboard, focus, contrast. Not optional. - [Interaction and feedback](references/interaction-and-feedback.md) – affordances, feedback rules, loading states, error prevention/recovery, progressive disclosure. - [Information architecture](references/information-architecture.md) – screens, navigation, flows, mental models. The source of `ia.md`. - [Design systems and tokens](references/design-systems-and-tokens.md) – tokens as source of truth, consistency, component reuse, the `design-guide.md` / `.json` relationship. - [Testable UI](references/testable-ui.md) – testable frameworks, stable seams, deterministic rendering, boundary-layer rendering, design-adherence at the E2E layer. ## Hard rules 1. **No silent failures, no unacknowledged success.** Every data-changing action shows visible success and failure feedback; feedback never shifts layout. 2. **Accessibility is not optional.** Keyboard-navigable, screen-reader-friendly, sufficient contrast, labelled controls, defended by an a11y check. 3. **Consistency over novelty.** Reuse the design-guide tokens and standard components; one pattern per job. `design-guide.json` is the source of truth. 4. **Visual hierarchy guides the eye.** The most important action is the most prominent; importance maps to weight, size, position. 5. **Information architecture before pixels.** Screens, navigation, and flows are defined (`ia.md`) before styling. 6. **The UI is testable by construction.** Modern framework, deterministic render, stable seams; rendering lives in the boundary layer. See [testable-ui](references/testable-ui.md). 7. **Progressive disclosure.** Show what the user needs now; defer complexity behind intent. ## Composition - **`lakebase-sftdd-workflows`** – UX Designer authors `design-guide.{md,json}` + `ia.md` and sets the adherence contract; Test Strategist writes E2E scenarios + a11y checks against it (see [test-strategy](../lakebase-sftdd-workflows/references/test-strategy.md)); Driver builds UI that adheres. - **`architectural-design-principles`** – [testable-ui](references/testable-ui.md) shares the boundary-layer rule (templating is a boundary adapter) and the fitness-function model. - **`software-design-principles`** – clean-code naming applies to components and template partials too.