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baseline-ui

Original：🇺🇸 English

Translated

Quickly deslop UI code by fixing spacing, hierarchy, typography, and small layout issues. Use when the interface needs a fast cleanup or polish pass.

1installs

Sourcefellipeutaka/leon

Added on2026-07-27

NPX Install

npx skill4agent add fellipeutaka/leon baseline-ui

Tags

Translated version includes tags in frontmatter

frontend-ui-guidelines tailwind-css ui-components animation-standards layout-best-practices

SKILL.md Content

View Translation Comparison →

Baseline UI

Enforces an opinionated UI baseline to prevent AI-generated interface slop.

How to use

```
/baseline-ui
```
Apply these constraints to any UI work in this conversation.
```
/baseline-ui <file>
```
Review the file against all constraints below and output:
- violations (quote the exact line/snippet)
- why it matters (1 short sentence)
- a concrete fix (code-level suggestion)

Stack

MUST use Tailwind CSS defaults unless custom values already exist or are explicitly requested
MUST use
```
motion/react
```
(formerly
```
framer-motion
```
) when JavaScript animation is required
SHOULD use
```
tw-animate-css
```
for entrance and micro-animations in Tailwind CSS
MUST use
```
cn
```
utility (
```
clsx
```
+
```
tailwind-merge
```
) for class logic

Components

MUST use accessible component primitives for anything with keyboard or focus behavior (
```
Base UI
```
,
```
React Aria
```
,
```
Radix
```
)
MUST use the project’s existing component primitives first
NEVER mix primitive systems within the same interaction surface
SHOULD prefer
```
Base UI
```
for new primitives if compatible with the stack
MUST add an
```
aria-label
```
to icon-only buttons
NEVER rebuild keyboard or focus behavior by hand unless explicitly requested

Interaction

MUST use an
```
AlertDialog
```
for destructive or irreversible actions
SHOULD use structural skeletons for loading states
NEVER use
```
h-screen
```
, use
```
h-dvh
```
MUST respect
```
safe-area-inset
```
for fixed elements
MUST show errors next to where the action happens
NEVER block paste in
```
input
```
or
```
textarea
```
elements

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 avoid animating paint properties (
```
background
```
,
```
color
```
) except for small, local UI (text, icons)
SHOULD use
```
ease-out
```
on entrance
NEVER exceed
```
200ms
```
for interaction feedback
MUST pause looping animations when off-screen
SHOULD respect
```
prefers-reduced-motion
```
NEVER introduce custom easing curves unless explicitly requested
SHOULD avoid animating large images or full-screen surfaces

Typography

MUST use
```
text-balance
```
for headings and
```
text-pretty
```
for body/paragraphs
MUST use
```
tabular-nums
```
for data
SHOULD use
```
truncate
```
or
```
line-clamp
```
for dense UI
NEVER modify
```
letter-spacing
```
(
```
tracking-*
```
) unless explicitly requested

Layout

MUST use a fixed
```
z-index
```
scale (no arbitrary
```
z-*
```
)
SHOULD use
```
size-*
```
for square elements instead of
```
w-*
```
+
```
h-*
```

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

Design

NEVER use gradients unless explicitly requested
NEVER use purple or multicolor gradients
NEVER use glow effects as primary affordances
SHOULD use Tailwind CSS default shadow scale unless explicitly requested
MUST give empty states one clear next action
SHOULD limit accent color usage to one per view
SHOULD use existing theme or Tailwind CSS color tokens before introducing new ones