sleak

Sleak

Better design decisions for interfaces that feel intentional, not assembled from defaults.

Works for designers reviewing work, engineers implementing UI, and agents assisting either. The rules are craft and hierarchy, not tool-specific. Read them directly or load this skill when you want a structured audit.

Core principles

These rules define this skill. Check them first on every audit.

1. Concentric corner radius

Nested rounded elements must follow one relationship:

parent − padding = child
parent − child   = padding
child  + padding = parent

Either the parent or child radius drives; padding is the gap between curves. Never reuse the same radius on both layers when padding > 0.

→ Full rules, CSS, and audit: references/concentric-radius.md

2. Section eyebrows

Small kickers above section headings ("Features", "About", pills, overlines). Fine on one section; weak when repeated on every block. Hero: almost never, only a rare release/status callout, and even then prefer a badge, not an eyebrow.

→ Limits and fixes: references/section-eyebrows.md

3. Intentional accent use

Full accent color is scarce. Use it to pull the eye to the most important task on the page, not to decorate icons, borders, headings, or every card.

• One primary focal point at full saturation (main CTA or critical action)
• Secondary controls → neutral or outline
• Opacity tints of the accent → only where they support that primary path (selected, focus, progress)
• Extra full-chroma accent dilutes brand impact and scatters attention

→ Full tiers, tokens, and audit: references/color.md

Strength of guidance

Read every Sleak rule at the right strength:

• Invariant: correctness, accessibility, semantics, or broken geometry. Do not violate it without a concrete platform constraint.
• Strong default: Sleak's opinionated starting point. Depart when the product, content, or established system gives a better reason, and preserve the intent behind the rule.
• Contextual heuristic: a diagnostic, not a pass/fail law. Verify it on the rendered result.