Design & UX

> Master web font loading optimization — font-display strategies for FOIT/FOUT control, Unicode range subsetting, variable fonts for multi-weight reduction, WOFF2 compression, preloading critical fonts, self-hosting versus CDN delivery, and the Font Loading API for programmatic control.

> Measure and prevent unexpected layout shifts — elements visually moving after being rendered — by reserving space for dynamic content, handling font loading, setting explicit dimensions, and understanding the CLS scoring formula.

> Prevent cascading failures with circuit breaker, half-open state, and fallback logic.

> LLM-judgment-based design ceiling-raiser. Three branchable phases — CRITIQUE finds what's mediocre, POLISH applies high-craft moves, BENCHMARK scores against curated exemplars. The ceiling counterpart to harness-design (declared-intent enforcement, rule-based) and the design-pipeline floor audits.

> Clone objects using prototype registry and structured clone for deep copy scenarios.

> Detect design-system drift — hardcoded values where tokens exist, and raw HTML primitives where registered components exist. The rule-based floor of design-pipeline (detect half). Reports findings; never modifies source. Pairs with a separate align-design-system fixer skill (deferred to a sibling sub-project).

> Space as a design element — macro vs. micro whitespace, breathing room, density control, and whitespace as a signal of quality and luxury

> Directing attention through size, color, contrast, position, isolation, and motion — the system that tells the eye where to go first, second, and third

> Anatomy of type — x-height, ascenders, descenders, counters, serifs, stroke contrast, optical sizing, and how anatomy affects readability

> Establishing reading order through type — size, weight, color, spacing, case, and position as hierarchy signals

> Mathematical type scales — modular, major third, perfect fourth, golden ratio, custom scales, and when each is appropriate

> Temporal design — enter/exit asymmetry, stagger patterns, easing functions (ease-out for enter, ease-in for exit), duration by element size, interruptibility

> Token taxonomy covering primitive, semantic, and component tokens with naming conventions, aliasing chains, theme switching, and the token-to-code pipeline.

> UI state inventory — empty, loading, partial, error, success, offline, disabled, read-only, and how each state communicates system status

> Responsive as a design decision — content-first breakpoints, progressive disclosure, and treating every viewport as a first-class design target

> Optimizing for reading — line length (measure), line height (leading), paragraph spacing, text alignment, hyphenation, and reading patterns (F-pattern, Z-pattern)

> Building functional palettes — primary/secondary/accent selection, neutral scales, semantic colors, and tint/shade generation for production design systems

> Design system nomenclature for semantic and descriptive names, color naming, size naming, and maintaining consistent vocabulary across design and code.

> Purposeful animation — Disney's 12 principles adapted for UI, easing curves, duration guidelines, choreography, motion as feedback vs decoration, reducing motion

> Small moments that delight — trigger, rules, feedback, loops/modes (Dan Saffer's framework), when micro-interactions aid usability vs decoration

> Google's adaptive design language covering dynamic color extraction from wallpaper, HCT-based tonal palettes, elevation through tonal surface color rather than drop shadows, shape theming with corner families, and choreographed motion with shared-axis transitions.

> Image in design — art direction, aspect ratios, focal point composition, image treatments (duotone, overlay, blur), placeholder strategy, and the role of image as hero vs. supporting element

> Illustration system design — style consistency, spot vs. hero illustrations, illustration as brand voice, abstract vs. representational choices, and illustration tokens for systematic production

> Icon design principles — optical sizing, stroke consistency, pixel grid alignment, metaphor clarity, icon families, filled vs outlined states, and icon as a systematic visual language