Visual finish of interfaces - alignment, border radii, shadows and borders, icon consistency, typography usage, text contrast, state and focus styling - and avoiding the looks that read as AI-generated. Use when a screen feels off, before shipping UI, or when polishing details. For whether states exist at all, keyboard reach and alt text use ux-check; for words use ux-writing; for any duration or easing value use motion; for creating color and spacing variables use design-tokens.