What problem does it solve? UI implementation in Spec Kit projects often drifts into generic one-off styling that ignores the product's design system, and teams ship interface changes without visual or accessibility evidence. This Skill gates UI work against a committed DESIGN.md contract and requires platform-appropriate proof before closeout. ## Core Features & Use Cases - Design System Gate: Checks for DESIGN.md before substantive UI work and routes missing or thin design contracts to the sp-design workflow instead of inventing ad-hoc styling. - UI Reference Input Gate: Handles screenshots, Figma exports, mockups, and reference URLs through a ui-reference lane producing ui-brief.md and fidelity modes (approximate, high, inspiration). - Platform Rules & Evidence: Defines requirements for web, mobile, desktop, TUI, and CLI surfaces, including component state coverage and viewport screenshot evidence. - Use Case: When adding a new settings screen to a CLI tool, the Skill verifies DESIGN.md exists, requires a ui-brief.md for substantive changes, and demands terminal captures at narrow and normal widths before closeout. ## Quick Start Review this UI change against our DESIGN.md design system and tell me what evidence I need before closing out the task.
