Ui4 review
Review UI4 CSS migrations for proper token usage. Checks that CSS variables are used instead of hardcoded values.From its SKILL.md
npx -y skills add payloadcms/payload --skill ui4-reviewAssembled from the repository path, not quoted from the project. Check it against their README if it does not work.
SKILL.md
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UI4 Review
Reviews CSS changes and auto-fixes token violations.
Important: Palette vs Semantic Tokens
--ramp-* tokens are the raw color palette (e.g., --ramp-white-1000, --ramp-blue-500). These are used only in colors.css to define semantic tokens.
--color-* tokens are context-aware semantic tokens (e.g., --color-bg, --color-text-brand). These handle light/dark theming automatically.
Components and elements should ALWAYS use --color-* semantic tokens, never --ramp-* palette tokens directly.
/* ❌ BAD - using raw palette */
background: var(--ramp-white-1000);
/* ✅ GOOD - using semantic token */
background: var(--color-bg);
Process
Step 1: Get Changed CSS Files
git status --porcelain | grep '\.css$'
Or if a specific file is provided, use that directly.
Step 2: Parallel Violation Detection
Run these grep searches IN PARALLEL to detect all violation types at once:
# 1. SCSS Nesting Violations (BEM patterns that don't work in CSS)
grep -n '&__\|&--' "$FILE"
# 2. Hardcoded Spacing (px/rem values that should be tokens)
grep -nE ':\s*[0-9]+px|:\s*[0-9.]+rem' "$FILE"
# 3. Hardcoded Colors (hex, rgb, rgba - includes box-shadow)
grep -nE '#[0-9a-fA-F]{3,8}|rgba?\(' "$FILE"
# 4. Legacy Theme Variables
grep -nE 'var\(--theme-|var\(--style-|var\(--base\)' "$FILE"
# 5. Old Token Names (pre-UI4 naming)
grep -nE '\-\-bg-default|\-\-bg-secondary|\-\-text-default|\-\-text-secondary|\-\-icon-default|\-\-icon-secondary|\-\-border-default|\-\-border-strong' "$FILE"
# 6. Raw Palette Usage (should use semantic tokens instead)
# Skip this check for colors.css which defines the semantic tokens
grep -nE 'var\(--ramp-' "$FILE"
Invoke all 6 grep commands in a single parallel batch, then analyze results.
Note: Raw --ramp-* violations are only flagged in component CSS files, not in colors.css where they're used to define semantic tokens.
Step 3: Auto-Fix by Priority
- SCSS Nesting (breaks CSS entirely) — Fix first
- Legacy Variables (deprecated) — Replace with new tokens
- Old Token Names (pre-UI4) — Convert to
--color-*naming - Raw Palette Usage (
--ramp-*in components) — Replace with semantic--color-*tokens - Hardcoded Values (spacing, colors, radius) — Replace with tokens
Step 4: Report
After fixing, report:
- Total violations found
- Violations auto-fixed
- Violations that need manual review (no clear token match)
Violation Reference
SCSS Nesting (BREAKS CSS)
| Pattern | Issue | Fix |
|---|---|---|
&__element | BEM element concat | Use flat .block__element selector |
&--modifier | BEM modifier concat | Use flat .block--modifier selector |
.child { .parent--mod & } | Parent reference | Move to .parent--mod .child |
What DOES work: &:hover, &:focus, &::before, & .child
Spacing Tokens
| Value | Token |
|---|---|
| 4px / 0.25rem | --spacer-1 |
| 8px / 0.5rem | --spacer-2 |
| 12px / 0.75rem | --spacer-2-5 |
| 16px / 1rem | --spacer-3 |
| 24px / 1.5rem | --spacer-4 |
| 32px / 2rem | --spacer-5 |
| 40px / 2.5rem | --spacer-6 |
Rounding rules — ALWAYS round to nearest token:
| Pixel Range | Token | Notes |
|---|---|---|
| 0-2px | --spacer-0 | Use 0 |
| 3-6px | --spacer-1 (4px) | 5-6px rounds to 4px |
| 7-10px | --spacer-2 (8px) | 10px rounds DOWN to 8px |
| 11-14px | --spacer-2-5 (12px) | 13.33px rounds to 12px |
| 15-20px | --spacer-3 (16px) | 15px, 20px both round to 16px |
| 21-28px | --spacer-4 (24px) | |
| 29-36px | --spacer-5 (32px) | 30px rounds to 32px |
| 37-48px | --spacer-6 (40px) |
Rule: For values ≤ 40px, ALWAYS use a single token (no calc()). For values > 40px, use calc() with a spacer token.
Exceptions: 0, percentages, auto, inherit, -1px (for clip offsets)
Stroke Width Tokens
| Value | Token |
|---|---|
| 1px | --stroke-width-small |
Radius Tokens
| Value | Token |
|---|---|
| 2px / 0.125rem | --radius-small |
| 5px / 0.3125rem | --radius-medium |
| 13px / 0.8125rem | --radius-large |
| 9999px | --radius-full |
Elevation Tokens (Box Shadows)
Defined in packages/ui/src/css/elevations.css.
Never use hardcoded rgba() for box-shadows. Use elevation tokens instead:
| Token | Use Case |
|---|---|
--elevation-300-tooltip | Tooltips, small floating elements |
--elevation-400-menu-panel | Menus, dropdowns, floating panels |
--elevation-500-modal-window | Modals, dialogs, full overlays |
/* ❌ BAD - hardcoded shadow */
box-shadow: 0 -2px 16px -2px rgba(0, 0, 0, 0.2);
/* ✅ GOOD - elevation token */
box-shadow: var(--elevation-400-menu-panel);
Elevations automatically adjust for light/dark themes.
Semantic Color Tokens (UI4 Naming)
All semantic colors use the --color- prefix. The default category and variant are implicit.
| Old Name | New Name (UI4) |
|---|---|
--bg-default | --color-bg |
--bg-secondary | --color-bg-secondary |
--bg-hover | --color-bg-hover |
--bg-selected | --color-bg-selected |
--bg-brand | --color-bg-brand |
--bg-danger | --color-bg-danger |
--bg-success | --color-bg-success |
--bg-warning | --color-bg-warning |
--text-default | --color-text |
--text-secondary | --color-text-secondary |
--text-tertiary | --color-text-tertiary |
--text-brand | --color-text-brand |
--text-danger | --color-text-danger |
--text-success | --color-text-success |
--icon-default | --color-icon |
--icon-secondary | --color-icon-secondary |
--icon-tertiary | --color-icon-tertiary |
--icon-brand | --color-icon-brand |
--icon-danger | --color-icon-danger |
--border-default | --color-border |
--border-strong | --color-border-strong |
--border-selected | --color-border-selected |
--border-brand | --color-border-brand |
Legacy Variables (Replace Immediately)
| Legacy | Replacement |
|---|---|
--theme-elevation-0 | --color-bg |
--theme-elevation-50 | --color-bg-secondary |
--theme-elevation-100 | --color-border |
--theme-text | --color-text |
--style-radius-m | --radius-medium |
var(--base) Conversion: Legacy token = 20px. Convert using:
| Original | Pixels | Replacement |
|---|---|---|
var(--base) * 0.4 | 8px | var(--spacer-2) |
var(--base) * 0.5 | 10px | calc(var(--spacer-1) * 2.5) |
var(--base) * 0.6 | 12px | var(--spacer-2-5) |
var(--base) | 20px | calc(var(--spacer-4) * 0.833) |
var(--base) * 2 | 40px | var(--spacer-6) |
See ui4 skill Step 1 for full conversion table.
Behavior
DO NOT just report violations. FIX THEM immediately using replace_string_in_file or multi_replace_string_in_file.
When a violation has no clear token match (e.g., 3px or an unusual rem value), flag it for manual review but don't guess.
For each violation:
- Identify the exact line and value
- Determine the correct token replacement
- Use
replace_string_in_fileto fix it immediately - Report what was fixed
Only flag (don't fix) when:
- No matching token exists (e.g., 18px badge size)
- Value is intentional (e.g.,
1pxborder,0) - Ambiguous replacement
Empty CSS files: If a component's CSS file becomes empty after migration (all styles now handled by shared components like Button), delete the CSS file and remove its import from the component.
Output Format
After auto-fixing, report:
## Auto-Fixed
✅ Collapsible/index.css:9 — `height: 2rem` → `height: var(--spacer-5)`
✅ Collapsible/index.css:120 — `width: 2rem` → `width: var(--spacer-5)`
## Flagged (Manual Review)
⚠️ ErrorPill/index.css:15 — `height: 1.125rem` (18px) — no matching token
Summary
After all fixes, provide a simple summary:
| File | Fixed | Flagged |
|---|---|---|
| Collapsible/index.css | 2 | 1 |
| ErrorPill/index.css | 0 | 2 |