/moai-ref-ui-polish

name: moai-ref-ui-polish
description: >
  UI polish and interface-completion reference: the small visual details — concentric
  border radius, optical alignment, shadow-vs-border, motion easing, typography
  smoothing, tabular numbers, icon stroke weight, hit areas — that separate polished
  interfaces from generic ones. Agent-extending skill that amplifies frontend/UI domain
  work with production-grade "interface taste" rules.
  NOT for: backend logic, database design, DevOps, security audits, non-UI work.

when_to_use: >
  Use for UI polish and design-completion work: building UI components, reviewing
  frontend code, implementing animations, hover/active states, shadows, borders,
  typography, icons, micro-interactions, enter/exit animations, or any visual detail
  work. Amplifies frontend domain work (manager-develop, Agent(general-purpose) with
  frontend instructions) with interface-design taste rules. Implementation examples are
  Web/CSS; the design principles are platform-neutral (apply to native mobile/desktop UI too).

user-invocable: false
metadata:
  version: "1.2.0"
  category: "domain"
  status: "active"
  updated: "2026-08-19"
  tags: "ui, polish, design, animation, typography, motion, frontend, accessibility, audit, reference"

# MoAI Extension: Progressive Disclosure
progressive_disclosure:
  enabled: true
  level1_tokens: 100
  level2_tokens: 5000

UI Polish Reference

Target Agents

• `manager-develop` - Applies polish rules during frontend/UI component implementation (`cycle_type=tdd` or `cycle_type=ddd` context)
• `/moai review` - UI-design review surface; equivalently available as a per-spawn `Agent(general-purpose)` frontend specialist per `archived-agent-rejection.md` §C

Core Philosophy

Great interfaces are a collection of small details that compound into a great experience. AI agents frequently miss these details — an `ease-in` easing on an enter animation (should be `ease-out`), a solid border where a semi-transparent shadow reads better, or mismatched radii on nested elements. None of these is catastrophic; together they separate "polished" from "generic".

Before suggesting polish changes, identify the project's existing styling system (design tokens, spacing scale, motion library). Never introduce a second styling system for polish fixes — extend the existing one.

Geometry and Alignment

| Principle | Rule | Rationale | |-----------|------|-----------| | Concentric Border Radius | `outerRadius = innerRadius + padding` | Mismatched radii on nested elements is the most common cause of an interface "feeling off" | | Optical over Geometric Alignment | When geometric centering looks wrong, align optically | Buttons with icons, play triangles, and asymmetric icons need a manual nudge; geometric center is visually off-center for these shapes |

Elevation and Structure

| Element | Use | Avoid | |---------|-----|-------| | Semi-transparent layered `box-shadow` | Depth, elevation, floating surfaces | Solid borders for depth (they read heavy and flat) | | Borders | Structure, dividers, separators, selected/focus state | Using shadows for structural separation (ambiguous) |

Motion

| Pattern | Rule | Common Mistake | |---------|------|----------------| | Enter animation easing | `ease-out` (decelerate) — element arrives calmly | `ease-in` on enter (element appears to slam into place) | | Exit animation easing | `ease-in` (accelerates away), mirroring the enter curve (small fixed `translateY`) | Full-height collapse, or harsher-than-enter motion | | Interruptible state changes | CSS `transition` (can be interrupted mid-animation) | `keyframes` for interactive states (cannot interrupt) | | Staged entrances | Stagger semantic chunks ~100ms — only for infrequent staged entrances | Staggering routine, high-frequency interactions (feels sluggish) | | Contextual icon animation | `opacity`/`scale`/`blur` cross-fade (scale 0.25→1, opacity 0→1, blur 4px→0) | Toggling `visibility` (jarring, no transition) | | Press feedback | `scale(0.96)` on click — always 0.96 | Smaller than 0.95 (reads as a bug, not a press) | | First-render enter | Skip with `initial={false}` on `AnimatePresence` (or equivalent) | Enter animation fires on page load (disorienting) | | Motion restraint | No custom animation on high-frequency interactions; motion is never the only feedback channel | Animating everything (noise, performance cost, accessibility) |

Motion Easing Values (Web/CSS)

| Case | Value | |------|-------| | With motion library (Framer Motion et al.) | `transition: { type: "spring", duration: 0.3, bounce: 0 }` | | Without motion library (CSS) | `cubic-bezier(0.2, 0, 0, 1)` for the standard "decelerate" curve | | Never | `transition: all` — always specify exact properties (`transition-property: scale, opacity`) |

Motion Accessibility and Cost

| Rule | Detail | |------|--------| | Reduced-motion branch (required) | Every non-decorative animation needs a `prefers-reduced-motion: reduce` path. Vestibular-disorder users are physically harmed by large-displacement and parallax motion. Reduce to an opacity cross-fade or remove the animation — never merely shorten it. The branch is authored at the same time as the animation, not retrofitted | | Animate the compositor, not the layout | `transform` and `opacity` are composited and skip layout and most paint. `width`, `height`, `top`, `left`, `margin`, and `padding` trigger layout on every frame (thrashing), which is why the same visual effect janks when driven by the wrong property. Move with `translate`, resize with `scale` |

> Motion principles behind these rules — the three decision passes, motion layers, the > 1/3 rules, stagger budgets, personality archetypes, Disney-adapted ranges, and the > emotion-to-motion map — live in `references/motion-principles.md` (L3, load on demand > when motion is the substance of the work).

Typography

| Rule | Implementation (Web/CSS) | When | |------|------------------