ui-design

# UI Design Patterns Reference for intentional visual design. Every choice must be justified. Sources in `references/sources.md`. ## Iron Law > **AESTHETICS MUST HAVE INTENT** [4][11] > > Every visual choice must be justified. Default styles, copied gradients, and > "looks modern" are not justifications. If you cannot explain why a specific > font, color, or animation exists, it's design debt. Good design is invisible > because it serves purpose — it satisfies mental models, not trends. > — Don Norman, *The Design of Everyday Things* [11]; Laws of UX [4] ## When This Skill Activates - Creating/styling UI components; reviewing CSS, Tailwind, or styled-components - Discussing typography, color schemes, layouts, or design systems --- ## 1. Typography [6][7][10][19] Font choice must match product personality: developer tools → monospace (precision), documentation → serif (readability), marketing → distinctive display. [6][7][27] Use a **mathematical type scale** (1.25 major third ratio). All sizes relate harmonically. [10] Line length: 45–75 characters for body text; `line-height: 1.7` for prose, `1.2` for headings. [6][7] Heading levels must differ in weight, tracking, and size — not size alone. [7][15] See `references/patterns.md` for scale values, font pairs, and heading styles. --- ## 2. Color System [1][9][12][14] **Three-layer token architecture** (Material Design 3 [1] + W3C Design Tokens spec [9]): ```css :root { --blue-600: #2563eb; /...