cal-ui-skills

Cal 的 UI 设计系统。适用于在构建界面时，以 Cal 的美学风格为灵感——采用浅色模式、Inter 字体、4px 网格。

SKILL.md

--- frontmatter

name: cal-ui-skills
description: Cal's UI design system. Use when building interfaces inspired by Cal's aesthetic - light mode, Inter font, 4px grid.
license: MIT
metadata:
  author: design-skills
  version: "1.0.0"
  source: https://cal.com

Cal UI Skills

Opinionated constraints for building Cal-style interfaces with AI agents.

When to Apply

Reference these guidelines when:

•Building light-mode interfaces
•Creating Cal-inspired design systems
•Implementing UIs with Inter font and 4px grid

Colors

•SHOULD use light backgrounds for primary surfaces
•MUST use #FDFDFD as page background (surface-base)
•SHOULD reduce color palette (currently 16 colors detected)
•MUST maintain text contrast ratio of at least 4.5:1 for accessibility

Semantic Tokens

Token	HEX	RGB	Usage
`surface-base`	#FDFDFD	rgb(253,253,253)	Page background
`surface-raised`	#EDEDED	rgb(237,237,237)	Cards, modals, raised surfaces
`surface-overlay`	#1C1C1C	rgb(28,28,28)	Overlays, tooltips, dropdowns
`text-primary`	#6B6B6B	rgb(107,107,107)	Headings, body text
`text-secondary`	#A1A1A1	rgb(161,161,161)	Secondary, muted text
`text-tertiary`	#404040	rgb(64,64,64)	Additional text
`border-default`	#E5E5E5	rgb(229,229,229)	Subtle borders, dividers
`destructive`	#FCC9C1	rgb(252,201,193)	Error states, delete actions

Typography

•MUST use Inter as primary font family
•SHOULD use single font family for consistency
•MUST use 70px / 700 for primary headings
•MUST use 16px / 400 for body text
•SHOULD reduce font weights (currently 5 detected)
•MUST use text-balance for headings and text-pretty for body text
•SHOULD use tabular-nums for numeric data
•NEVER modify letter-spacing unless explicitly requested

Text Styles

Style	Font	Size	Weight	Color	Count
`heading-1`	Inter	70px	700	#2A2A2A	1
`text-23px`	Inter	23px	semi_bold	#C1C1C1	1
`text-22px`	Inter	22px	semi_bold	#494949	1
`text-21px`	Inter	21px	500	#676767	1
`text-21px`	Inter	21px	semi_bold	#383838	1
`text-19px`	Inter	19px	500	#2C2C2C	1
`text-19px`	Inter	19px	500	#3C3C3C	1
`text-19px`	Inter	19px	500	#D4D4D4	1
`text-18px`	Inter	18px	500	#404040	1
`body`	Inter	16px	400	#A4A4A4	1

Typography Reference

Font Families:

•Inter (used 65x)

Font Sizes: 8px, 9px, 10px, 11px, 12px, 13px, 14px, 15px, 16px, 18px, 19px, 21px, 22px, 23px, 70px

Spacing

•MUST use 4px grid for spacing
•SHOULD use spacing from scale: 1px, 2px, 3px, 4px, 5px, 6px, 7px, 9px
•SHOULD use 5px as default gap between elements
•NEVER use arbitrary spacing values (use design scale)
•SHOULD maintain consistent padding within containers

Borders

•MUST use border-radius from scale: 1px, 2px, 3px, 4px, 6px, 7px, 8px, 9px, 10px, 11px
•SHOULD limit border widths to: 1px, 3px
•SHOULD use 3px as default border-radius
•NEVER use arbitrary border-radius values (use design scale)
•SHOULD use subtle borders (1px) for element separation

Border Radius Reference

Scale: 1px, 2px, 3px, 4px, 6px, 7px, 8px, 9px, 10px, 11px

Layout

•MUST design for 1920px base viewport width
•SHOULD use consistent element widths: 16px, 8px, 11px, 10px, 52px
•SHOULD maintain text-heavy layout with clear hierarchy
•NEVER use h-screen, use h-dvh for full viewport height
•MUST respect safe-area-inset for fixed elements
•SHOULD use size-* for square elements instead of w-* + h-*

Detected Layout Patterns

•Main Content: width: 1565px, height: 814px
•Main Content: width: 1920px, height: 1080px
•Main Content: width: 1180px, height: 717px
•Main Content: width: 1178px, height: 701px

Components

Buttons

Variant	Background	Text	Border	Height	Radius
Ghost	transparent	#6B6B6B	none	-	-

Interactive States

Focus

•MUST use 2px outline with accent color (#5E6AD2)
•MUST use 2px outline-offset
•NEVER remove focus indicators

Hover

•Buttons (primary): lighten background by 10%
•Buttons (secondary): use #EDEDED background
•List items: use #EDEDED background

Disabled

•MUST use opacity: 0.5
•MUST use cursor: not-allowed

Interaction

•MUST use an AlertDialog for destructive or irreversible actions
•SHOULD use structural skeletons for loading states
•MUST show errors next to where the action happens
•NEVER block paste in input or textarea elements
•MUST add an aria-label to icon-only buttons

Animation

•NEVER add animation unless it is explicitly requested
•MUST animate only compositor props (transform, opacity)
•NEVER animate layout properties (width, height, top, left, margin, padding)
•SHOULD use ease-out on entrance animations
•NEVER exceed 200ms for interaction feedback
•SHOULD respect prefers-reduced-motion

Performance

•NEVER animate large blur() or backdrop-filter surfaces
•NEVER apply will-change outside an active animation
•NEVER use useEffect for anything that can be expressed as render logic