feat 🥁: add no-unitless-values rule

- Disallow unitless numeric values for CSS properties that require units (e.g., width: 100 should be width: 100px)
- Allow zero values and unitless-valid properties (opacity, zIndex, lineHeight)
- Support both numeric literals and string literals with unitless numbers
- Configurable allowlist via 'allow' option

CHANGELOG.md

@@ -5,6 +5,14 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/), and this project adheres to
 [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.16.0] - 2025-12-01
+
+- Add new rule `no-unitless-values` that disallows unitless numeric values for CSS properties that require units ([issue #6](https://github.com/antebudimir/eslint-plugin-vanilla-extract/issues/6))
+  - Flags both numeric literals (e.g., `width: 100`) and string literals with unitless numbers (e.g., `width: '100'`)
+  - Allows zero values without units (valid CSS) and properties that accept unitless values (opacity, zIndex, lineHeight, etc.)
+  - Configurable allowlist via `allow` option to exclude specific properties from checking
+  - Optional rule (not included in recommended config) - teams can enable when they prefer explicit units over vanilla-extract's automatic px conversion
+
 ## [1.15.1] - 2025-11-22
 
 - Fix [issue #7](https://github.com/antebudimir/eslint-plugin-vanilla-extract/issues/7) to prevent false positives for `sprinkles()`/`style()`/`recipe()` calls with non-empty object arguments while continuing to flag bare `({})` calls

README.md

@@ -264,6 +264,7 @@ The recommended configuration enables the following rules with error severity:
 - `vanilla-extract/alphabetical-order`: Alternative ordering rule (alphabetical sorting)
 - `vanilla-extract/custom-order`: Alternative ordering rule (custom group-based sorting)
 - `vanilla-extract/no-px-unit`: Disallows px units with an optional allowlist
+- `vanilla-extract/no-unitless-values`: Disallows unitless numeric values for CSS properties that require units
 - `vanilla-extract/prefer-logical-properties`: Enforces logical CSS properties over physical directional properties
 - `vanilla-extract/prefer-theme-tokens`: Enforces theme tokens instead of hard-coded values for colors, spacing, font sizes, border radius, border widths, shadows, z-index, opacity, font weights, and transitions/animations (optionally evaluates helper functions and template literals)
 
@@ -536,6 +537,77 @@ export const myStyle = style({
 });
 ```
 
+### vanilla-extract/no-unitless-values
+
+This rule disallows unitless numeric values for CSS properties that require units in vanilla-extract style objects. It helps teams that prefer explicit units avoid confusion, as vanilla-extract automatically converts unitless numbers to `px` at runtime.
+
+**Note:** This is an optional rule (not enabled in recommended config). Enable it only if your team prefers explicit units over vanilla-extract's automatic `px` conversion.
+
+Configuration with allowed properties:
+
+```json
+{
+  "rules": {
+    "vanilla-extract/no-unitless-values": ["warn", { "allow": ["width", "height"] }]
+  }
+}
+```
+
+```typescript
+// ❌ Incorrect
+import { style } from '@vanilla-extract/css';
+
+export const myStyle = style({
+  width: 100,
+  margin: 20,
+  padding: 10.5,
+  height: '50',
+  top: '-10',
+});
+
+// ✅ Correct
+import { style } from '@vanilla-extract/css';
+
+export const myStyle = style({
+  width: '100px',
+  margin: '20px',
+  padding: 0,
+  height: '50rem',
+  opacity: 0.5,      // opacity accepts unitless values
+  lineHeight: 1.5,   // line-height accepts unitless values
+  zIndex: 10,        // z-index accepts unitless values
+});
+```
+
+**Properties that require units:**
+
+- **Box model:** `width`, `height`, `minWidth`, `maxWidth`, `minHeight`, `maxHeight`, `min-width`, `max-width`, `min-height`, `max-height`
+- **Spacing:** `margin`, `marginTop`, `marginRight`, `marginBottom`, `marginLeft`, `marginBlock`, `marginBlockStart`, `marginBlockEnd`, `marginInline`, `marginInlineStart`, `marginInlineEnd`, `margin-top`, `margin-right`, `margin-bottom`, `margin-left`, `margin-block`, `margin-block-start`, `margin-block-end`, `margin-inline`, `margin-inline-start`, `margin-inline-end`, `padding`, `paddingTop`, `paddingRight`, `paddingBottom`, `paddingLeft`, `paddingBlock`, `paddingBlockStart`, `paddingBlockEnd`, `paddingInline`, `paddingInlineStart`, `paddingInlineEnd`, `padding-top`, `padding-right`, `padding-bottom`, `padding-left`, `padding-block`, `padding-block-start`, `padding-block-end`, `padding-inline`, `padding-inline-start`, `padding-inline-end`
+- **Positioning:** `top`, `right`, `bottom`, `left`, `inset`, `insetBlock`, `insetBlockStart`, `insetBlockEnd`, `insetInline`, `insetInlineStart`, `insetInlineEnd`, `inset-block`, `inset-block-start`, `inset-block-end`, `inset-inline`, `inset-inline-start`, `inset-inline-end`
+- **Border:** `borderWidth`, `borderTopWidth`, `borderRightWidth`, `borderBottomWidth`, `borderLeftWidth`, `borderBlockWidth`, `borderBlockStartWidth`, `borderBlockEndWidth`, `borderInlineWidth`, `borderInlineStartWidth`, `borderInlineEndWidth`, `border-width`, `border-top-width`, `border-right-width`, `border-bottom-width`, `border-left-width`, `border-block-width`, `border-block-start-width`, `border-block-end-width`, `border-inline-width`, `border-inline-start-width`, `border-inline-end-width`, `borderRadius`, `borderTopLeftRadius`, `borderTopRightRadius`, `borderBottomLeftRadius`, `borderBottomRightRadius`, `borderStartStartRadius`, `borderStartEndRadius`, `borderEndStartRadius`, `borderEndEndRadius`, `border-radius`, `border-top-left-radius`, `border-top-right-radius`, `border-bottom-left-radius`, `border-bottom-right-radius`, `border-start-start-radius`, `border-start-end-radius`, `border-end-start-radius`, `border-end-end-radius`
+- **Typography:** `fontSize`, `font-size`, `letterSpacing`, `letter-spacing`, `wordSpacing`, `word-spacing`, `textIndent`, `text-indent`
+- **Layout:** `gap`, `rowGap`, `columnGap`, `row-gap`, `column-gap`, `flexBasis`, `flex-basis`
+- **Outline:** `outlineWidth`, `outline-width`, `outlineOffset`, `outline-offset`
+- **Other:** `blockSize`, `inlineSize`, `minBlockSize`, `maxBlockSize`, `minInlineSize`, `maxInlineSize`, `block-size`, `inline-size`, `min-block-size`, `max-block-size`, `min-inline-size`, `max-inline-size`
+
+**Properties that accept unitless values:**
+
+- **Common:** `opacity`, `zIndex`, `z-index`, `lineHeight`, `line-height`, `flexGrow`, `flex-grow`, `flexShrink`, `flex-shrink`, `order`, `fontWeight`, `font-weight`, `zoom`
+- **Animation:** `animationIterationCount`, `animation-iteration-count`
+- **Layout:** `columnCount`, `column-count`, `orphans`, `widows`
+- **Grid:** `gridColumn`, `grid-column`, `gridColumnEnd`, `grid-column-end`, `gridColumnStart`, `grid-column-start`, `gridRow`, `grid-row`, `gridRowEnd`, `grid-row-end`, `gridRowStart`, `grid-row-start`
+- **SVG:** `fillOpacity`, `fill-opacity`, `strokeOpacity`, `stroke-opacity`, `strokeMiterlimit`, `stroke-miterlimit`
+
+**Why use this rule?**
+
+While vanilla-extract safely converts unitless numbers to `px`, some teams prefer explicit units because:
+
+1. It makes the intended unit clear (px, rem, em, %, etc.)
+2. It prevents accidental use of px when rem or other units are preferred
+3. It aligns with CSS best practices of being explicit about units
+
+**Auto-fix:** Not available. Since different teams prefer different units (px, rem, em, %), you must manually add your preferred unit.
+
 ### vanilla-extract/no-unknown-unit
 
 This rule enforces the use of valid CSS units in vanilla-extract style objects. It prevents typos and non-standard units
@@ -835,10 +907,7 @@ The roadmap outlines the project's current status and future plans:
 - `no-px-unit` rule to disallow use of `px` units with configurable whitelist.
 - `prefer-logical-properties` rule to enforce use of logical properties.
 - `prefer-theme-tokens` rule to enforce theme tokens instead of hard-coded values for colors, spacing, font sizes, border radius, border widths, shadows, z-index, opacity, font weights, and transitions/animations (optionally evaluates helper functions and template literals).
-
-### Current Work
-
-- `no-unitless-values` rule that disallows numeric literals for CSS properties that are not unitless in CSS.
+- `no-unitless-values` rule to disallow unitless numeric values for CSS properties that require units.
 
 ### Upcoming Features
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@antebudimir/eslint-plugin-vanilla-extract",
-  "version": "1.15.1",
+  "version": "1.16.0",
   "description": "Comprehensive ESLint plugin for vanilla-extract with CSS property ordering, style validation, and best practices enforcement. Supports alphabetical, concentric and custom CSS ordering, auto-fixing, and zero-runtime safety.",
   "author": "Ante Budimir",
   "license": "MIT",

src/css-rules/no-trailing-zero/index.ts

@@ -1 +1,3 @@
-export { default } from './rule-definition.js';
+import noTrailingZeroRule from './rule-definition.js';
+
+export default noTrailingZeroRule;

src/css-rules/no-unitless-values/_tests_/no-unitless-values.test.ts

@@ -0,0 +1,472 @@
+import tsParser from '@typescript-eslint/parser';
+import { run } from 'eslint-vitest-rule-tester';
+import noUnitlessValuesRule from '../rule-definition.js';
+
+run({
+  name: 'vanilla-extract/no-unitless-values',
+  rule: noUnitlessValuesRule,
+  languageOptions: {
+    parser: tsParser,
+    parserOptions: {
+      ecmaVersion: 2022,
+      sourceType: 'module',
+    },
+  },
+  valid: [
+    // Zero values are allowed
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          margin: 0,
+          padding: 0,
+          width: 0,
+        });
+      `,
+      name: 'should allow zero values without units',
+    },
+
+    // String values with units
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          width: '100px',
+          margin: '20px',
+          padding: '1rem',
+          fontSize: '16px',
+        });
+      `,
+      name: 'should allow string values with units',
+    },
+
+    // String zero values
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          margin: '0',
+          padding: '0',
+        });
+      `,
+      name: 'should allow string zero values without units',
+    },
+
+    // Unitless-valid properties
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          opacity: 0.5,
+          zIndex: 10,
+          lineHeight: 1.5,
+          flexGrow: 1,
+          flexShrink: 0,
+          order: 2,
+          fontWeight: 700,
+          zoom: 1.2,
+        });
+      `,
+      name: 'should allow unitless values for properties that accept them',
+    },
+
+    // Recipe with valid values
+    {
+      code: `
+        import { recipe } from '@vanilla-extract/css';
+        const myRecipe = recipe({
+          base: {
+            margin: '0',
+            padding: 0,
+            opacity: 0.8,
+          },
+          variants: {
+            size: {
+              small: {
+                height: '10px',
+                width: '10px',
+                zIndex: 1,
+              },
+            },
+          },
+        });
+      `,
+      name: 'should allow valid values in recipe',
+    },
+
+    // Template literals (not checked)
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          margin: \`\${someValue}px\`,
+          padding: someVariable,
+        });
+      `,
+      name: 'should ignore template literals and variables',
+    },
+
+    // Nested selectors with valid values
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          width: '100px',
+          ':hover': {
+            margin: '20px',
+            opacity: 0.8,
+          },
+        });
+      `,
+      name: 'should allow valid values in nested selectors',
+    },
+
+    // Media queries with valid values
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          margin: 0,
+          '@media': {
+            '(min-width: 768px)': {
+              padding: '20px',
+              zIndex: 10,
+            }
+          }
+        });
+      `,
+      name: 'should allow valid values in media queries',
+    },
+
+    // globalStyle with valid values
+    {
+      code: `
+        import { globalStyle } from '@vanilla-extract/css';
+        globalStyle('html', {
+          margin: '0',
+          padding: 0,
+          lineHeight: 1.5,
+        });
+      `,
+      name: 'should allow valid values in globalStyle',
+    },
+
+    // fontFace with valid values
+    {
+      code: `
+        import { fontFace } from '@vanilla-extract/css';
+        fontFace({
+          src: 'url(...)',
+          fontWeight: 400,
+        });
+      `,
+      name: 'should allow valid values in fontFace',
+    },
+
+    // keyframes (animation values are strings)
+    {
+      code: `
+        import { keyframes } from '@vanilla-extract/css';
+        const spin = keyframes({
+          '0%': { transform: 'rotate(0deg)' },
+          '100%': { transform: 'rotate(360deg)' }
+        });
+      `,
+      name: 'should allow keyframes with string values',
+    },
+
+    // allow option
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          width: 100,
+          margin: '20px',
+        });
+      `,
+      options: [{ allow: ['width'] }],
+      name: 'should allow properties specified in allow option',
+    },
+
+    // Kebab-case unitless-valid properties
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          'z-index': 10,
+          'line-height': 1.5,
+          'flex-grow': 1,
+        });
+      `,
+      name: 'should allow unitless values for kebab-case unitless-valid properties',
+    },
+  ],
+
+  invalid: [
+    // Basic unitless values
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          width: 100,
+          margin: 20,
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'width', value: '100' } },
+        { messageId: 'noUnitlessValue', data: { property: 'margin', value: '20' } },
+      ],
+      name: 'should flag unitless numeric values for length properties',
+    },
+
+    // Decimal values
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          padding: 10.5,
+          fontSize: 16.5,
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'padding', value: '10.5' } },
+        { messageId: 'noUnitlessValue', data: { property: 'fontSize', value: '16.5' } },
+      ],
+      name: 'should flag decimal unitless values',
+    },
+
+    // Recipe with unitless values
+    {
+      code: `
+        import { recipe } from '@vanilla-extract/css';
+        const myRecipe = recipe({
+          base: {
+            margin: 10,
+          },
+          variants: {
+            size: {
+              small: {
+                height: 20,
+              },
+            },
+          },
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'margin', value: '10' } },
+        { messageId: 'noUnitlessValue', data: { property: 'height', value: '20' } },
+      ],
+      name: 'should flag unitless values in recipe',
+    },
+
+    // Nested selectors with unitless values
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          width: 100,
+          ':hover': {
+            margin: 20,
+          },
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'width', value: '100' } },
+        { messageId: 'noUnitlessValue', data: { property: 'margin', value: '20' } },
+      ],
+      name: 'should flag unitless values in nested selectors',
+    },
+
+    // Media queries with unitless values
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          '@media': {
+            '(min-width: 768px)': {
+              padding: 20,
+            }
+          }
+        });
+      `,
+      errors: [{ messageId: 'noUnitlessValue', data: { property: 'padding', value: '20' } }],
+      name: 'should flag unitless values in media queries',
+    },
+
+    // Multiple levels of nesting
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          margin: 10,
+          nested: {
+            object: {
+              padding: 20,
+              deeper: {
+                width: 30
+              }
+            }
+          }
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'margin', value: '10' } },
+        { messageId: 'noUnitlessValue', data: { property: 'padding', value: '20' } },
+        { messageId: 'noUnitlessValue', data: { property: 'width', value: '30' } },
+      ],
+      name: 'should flag unitless values in deeply nested objects',
+    },
+
+    // globalStyle with unitless values
+    {
+      code: `
+        import { globalStyle } from '@vanilla-extract/css';
+        globalStyle('html', {
+          margin: 10,
+          padding: 20,
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'margin', value: '10' } },
+        { messageId: 'noUnitlessValue', data: { property: 'padding', value: '20' } },
+      ],
+      name: 'should flag unitless values in globalStyle',
+    },
+
+    // Various length properties
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          width: 100,
+          height: 200,
+          minWidth: 50,
+          maxWidth: 500,
+          top: 10,
+          left: 20,
+          borderWidth: 2,
+          borderRadius: 5,
+          gap: 15,
+          fontSize: 16,
+        });
+      `,
+      errors: 10,
+      name: 'should flag all unitless values for various length properties',
+    },
+
+    // Kebab-case properties
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          'margin-top': 10,
+          'padding-left': 20,
+          'font-size': 16,
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'margin-top', value: '10' } },
+        { messageId: 'noUnitlessValue', data: { property: 'padding-left', value: '20' } },
+        { messageId: 'noUnitlessValue', data: { property: 'font-size', value: '16' } },
+      ],
+      name: 'should flag unitless values for kebab-case properties',
+    },
+
+    // Logical properties
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          marginBlock: 10,
+          paddingInline: 20,
+          insetBlockStart: 5,
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'marginBlock', value: '10' } },
+        { messageId: 'noUnitlessValue', data: { property: 'paddingInline', value: '20' } },
+        { messageId: 'noUnitlessValue', data: { property: 'insetBlockStart', value: '5' } },
+      ],
+      name: 'should flag unitless values for logical properties',
+    },
+
+    // styleVariants
+    {
+      code: `
+        import { styleVariants } from '@vanilla-extract/css';
+        const variants = styleVariants({
+          small: { width: 10 },
+          large: { width: 100 },
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'width', value: '10' } },
+        { messageId: 'noUnitlessValue', data: { property: 'width', value: '100' } },
+      ],
+      name: 'should flag unitless values in styleVariants',
+    },
+
+    // globalKeyframes
+    {
+      code: `
+        import { globalKeyframes } from '@vanilla-extract/css';
+        globalKeyframes('slide', {
+          '0%': { left: 0 },
+          '100%': { left: 100 }
+        });
+      `,
+      errors: [{ messageId: 'noUnitlessValue', data: { property: 'left', value: '100' } }],
+      name: 'should flag unitless values in globalKeyframes',
+    },
+
+    // Negative values
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          margin: -10,
+          top: -5,
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'margin', value: '-10' } },
+        { messageId: 'noUnitlessValue', data: { property: 'top', value: '-5' } },
+      ],
+      name: 'should flag negative unitless values',
+    },
+
+    // String unitless values
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          width: '100',
+          margin: '20',
+          padding: '10.5',
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'width', value: '100' } },
+        { messageId: 'noUnitlessValue', data: { property: 'margin', value: '20' } },
+        { messageId: 'noUnitlessValue', data: { property: 'padding', value: '10.5' } },
+      ],
+      name: 'should flag string unitless values',
+    },
+
+    // String negative unitless values
+    {
+      code: `
+        import { style } from '@vanilla-extract/css';
+        const myStyle = style({
+          margin: '-10',
+          top: '-5.5',
+        });
+      `,
+      errors: [
+        { messageId: 'noUnitlessValue', data: { property: 'margin', value: '-10' } },
+        { messageId: 'noUnitlessValue', data: { property: 'top', value: '-5.5' } },
+      ],
+      name: 'should flag string negative unitless values',
+    },
+  ],
+});

src/css-rules/no-unitless-values/index.ts

@@ -0,0 +1,3 @@
+import noUnitlessValuesRule from './rule-definition.js';
+
+export default noUnitlessValuesRule;

src/css-rules/no-unitless-values/rule-definition.ts

@@ -0,0 +1,40 @@
+import type { Rule } from 'eslint';
+import { createUnitlessValueVisitors } from './unitless-value-visitor-creator.js';
+import type { NoUnitlessValuesOptions } from './unitless-value-processor.js';
+
+const noUnitlessValuesRule: Rule.RuleModule = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      description: 'disallow unitless numeric values for CSS properties that require units',
+      category: 'Stylistic Issues',
+      recommended: false,
+    },
+    schema: [
+      {
+        type: 'object',
+        properties: {
+          allow: {
+            type: 'array',
+            items: {
+              type: 'string',
+            },
+            uniqueItems: true,
+            default: [],
+          },
+        },
+        additionalProperties: false,
+      },
+    ],
+    messages: {
+      noUnitlessValue:
+        'Property "{{ property }}" has unitless value {{ value }}. Add an explicit unit (e.g., "{{ value }}px", "{{ value }}rem").',
+    },
+  },
+  create(context) {
+    const options: NoUnitlessValuesOptions = (context.options[0] as NoUnitlessValuesOptions | undefined) || {};
+    return createUnitlessValueVisitors(context, options);
+  },
+};
+
+export default noUnitlessValuesRule;

src/css-rules/no-unitless-values/unitless-value-processor.ts

@@ -0,0 +1,371 @@
+import type { Rule } from 'eslint';
+import { AST_NODE_TYPES, TSESTree } from '@typescript-eslint/utils';
+
+/**
+ * CSS properties that require units for length/dimension values.
+ * These properties should not have unitless numeric values (except 0).
+ */
+const PROPERTIES_REQUIRING_UNITS = new Set([
+  // Box model
+  'width',
+  'height',
+  'minWidth',
+  'maxWidth',
+  'minHeight',
+  'maxHeight',
+  'min-width',
+  'max-width',
+  'min-height',
+  'max-height',
+
+  // Spacing
+  'margin',
+  'marginTop',
+  'marginRight',
+  'marginBottom',
+  'marginLeft',
+  'marginBlock',
+  'marginBlockStart',
+  'marginBlockEnd',
+  'marginInline',
+  'marginInlineStart',
+  'marginInlineEnd',
+  'margin-top',
+  'margin-right',
+  'margin-bottom',
+  'margin-left',
+  'margin-block',
+  'margin-block-start',
+  'margin-block-end',
+  'margin-inline',
+  'margin-inline-start',
+  'margin-inline-end',
+
+  'padding',
+  'paddingTop',
+  'paddingRight',
+  'paddingBottom',
+  'paddingLeft',
+  'paddingBlock',
+  'paddingBlockStart',
+  'paddingBlockEnd',
+  'paddingInline',
+  'paddingInlineStart',
+  'paddingInlineEnd',
+  'padding-top',
+  'padding-right',
+  'padding-bottom',
+  'padding-left',
+  'padding-block',
+  'padding-block-start',
+  'padding-block-end',
+  'padding-inline',
+  'padding-inline-start',
+  'padding-inline-end',
+
+  // Positioning
+  'top',
+  'right',
+  'bottom',
+  'left',
+  'inset',
+  'insetBlock',
+  'insetBlockStart',
+  'insetBlockEnd',
+  'insetInline',
+  'insetInlineStart',
+  'insetInlineEnd',
+  'inset-block',
+  'inset-block-start',
+  'inset-block-end',
+  'inset-inline',
+  'inset-inline-start',
+  'inset-inline-end',
+
+  // Border
+  'borderWidth',
+  'borderTopWidth',
+  'borderRightWidth',
+  'borderBottomWidth',
+  'borderLeftWidth',
+  'borderBlockWidth',
+  'borderBlockStartWidth',
+  'borderBlockEndWidth',
+  'borderInlineWidth',
+  'borderInlineStartWidth',
+  'borderInlineEndWidth',
+  'border-width',
+  'border-top-width',
+  'border-right-width',
+  'border-bottom-width',
+  'border-left-width',
+  'border-block-width',
+  'border-block-start-width',
+  'border-block-end-width',
+  'border-inline-width',
+  'border-inline-start-width',
+  'border-inline-end-width',
+
+  'borderRadius',
+  'borderTopLeftRadius',
+  'borderTopRightRadius',
+  'borderBottomLeftRadius',
+  'borderBottomRightRadius',
+  'borderStartStartRadius',
+  'borderStartEndRadius',
+  'borderEndStartRadius',
+  'borderEndEndRadius',
+  'border-radius',
+  'border-top-left-radius',
+  'border-top-right-radius',
+  'border-bottom-left-radius',
+  'border-bottom-right-radius',
+  'border-start-start-radius',
+  'border-start-end-radius',
+  'border-end-start-radius',
+  'border-end-end-radius',
+
+  // Typography
+  'fontSize',
+  'font-size',
+  'letterSpacing',
+  'letter-spacing',
+  'wordSpacing',
+  'word-spacing',
+  'textIndent',
+  'text-indent',
+
+  // Flexbox/Grid
+  'gap',
+  'rowGap',
+  'columnGap',
+  'row-gap',
+  'column-gap',
+  'flexBasis',
+  'flex-basis',
+
+  // Outline
+  'outlineWidth',
+  'outline-width',
+  'outlineOffset',
+  'outline-offset',
+
+  // Other
+  'blockSize',
+  'inlineSize',
+  'minBlockSize',
+  'maxBlockSize',
+  'minInlineSize',
+  'maxInlineSize',
+  'block-size',
+  'inline-size',
+  'min-block-size',
+  'max-block-size',
+  'min-inline-size',
+  'max-inline-size',
+]);
+
+/**
+ * CSS properties that accept unitless numeric values.
+ * These properties should NOT be flagged when they have numeric values.
+ */
+const UNITLESS_VALID_PROPERTIES = new Set([
+  'opacity',
+  'zIndex',
+  'z-index',
+  'lineHeight',
+  'line-height',
+  'flexGrow',
+  'flex-grow',
+  'flexShrink',
+  'flex-shrink',
+  'order',
+  'fontWeight',
+  'font-weight',
+  'zoom',
+  'animationIterationCount',
+  'animation-iteration-count',
+  'columnCount',
+  'column-count',
+  'gridColumn',
+  'grid-column',
+  'gridColumnEnd',
+  'grid-column-end',
+  'gridColumnStart',
+  'grid-column-start',
+  'gridRow',
+  'grid-row',
+  'gridRowEnd',
+  'grid-row-end',
+  'gridRowStart',
+  'grid-row-start',
+  'orphans',
+  'widows',
+  'fillOpacity',
+  'fill-opacity',
+  'strokeOpacity',
+  'stroke-opacity',
+  'strokeMiterlimit',
+  'stroke-miterlimit',
+]);
+
+export interface NoUnitlessValuesOptions {
+  allow?: string[];
+}
+
+/**
+ * Checks if a property name requires units for numeric values.
+ */
+const requiresUnits = (propertyName: string, allow: string[] = []): boolean => {
+  if (allow.includes(propertyName)) {
+    return false;
+  }
+
+  if (UNITLESS_VALID_PROPERTIES.has(propertyName)) {
+    return false;
+  }
+
+  return PROPERTIES_REQUIRING_UNITS.has(propertyName);
+};
+
+/**
+ * Gets the property name from a Property node.
+ */
+const getPropertyName = (property: TSESTree.Property): string | null => {
+  if (property.key.type === AST_NODE_TYPES.Identifier) {
+    return property.key.name;
+  }
+  if (property.key.type === AST_NODE_TYPES.Literal && typeof property.key.value === 'string') {
+    return property.key.value;
+  }
+  return null;
+};
+
+/**
+ * Recursively processes a style object, reporting instances of unitless numeric values for properties that require units.
+ *
+ * @param ruleContext The ESLint rule context.
+ * @param node The ObjectExpression node representing the style object to be processed.
+ * @param options Rule options including allow list.
+ */
+export const processUnitlessValueInStyleObject = (
+  ruleContext: Rule.RuleContext,
+  node: TSESTree.ObjectExpression,
+  options: NoUnitlessValuesOptions = {},
+): void => {
+  const allow = options.allow || [];
+
+  node.properties.forEach((property) => {
+    if (property.type !== AST_NODE_TYPES.Property) {
+      return;
+    }
+
+    const propertyName = getPropertyName(property);
+    if (!propertyName) {
+      return;
+    }
+
+    // Skip special nested structures like @media, selectors, etc.
+    // These will be processed recursively
+    if (propertyName.startsWith('@') || propertyName.startsWith(':') || propertyName === 'selectors') {
+      if (property.value.type === AST_NODE_TYPES.ObjectExpression) {
+        if (propertyName === '@media' || propertyName === 'selectors') {
+          property.value.properties.forEach((nestedProperty) => {
+            if (
+              nestedProperty.type === AST_NODE_TYPES.Property &&
+              nestedProperty.value.type === AST_NODE_TYPES.ObjectExpression
+            ) {
+              processUnitlessValueInStyleObject(ruleContext, nestedProperty.value, options);
+            }
+          });
+        } else {
+          // For pseudo-selectors and other nested objects, process directly
+          processUnitlessValueInStyleObject(ruleContext, property.value, options);
+        }
+      }
+      return;
+    }
+
+    // Check if this property requires units
+    if (!requiresUnits(propertyName, allow)) {
+      // Still need to process nested objects for non-CSS properties
+      if (property.value.type === AST_NODE_TYPES.ObjectExpression) {
+        processUnitlessValueInStyleObject(ruleContext, property.value, options);
+      }
+      return;
+    }
+
+    // Check for unitless numeric literal values (e.g., width: 100)
+    if (property.value.type === AST_NODE_TYPES.Literal && typeof property.value.value === 'number') {
+      // Allow 0 without units (valid CSS), including -0
+      if (property.value.value === 0 || property.value.value === -0) {
+        return;
+      }
+
+      // Report unitless numeric value
+      ruleContext.report({
+        node: property.value,
+        messageId: 'noUnitlessValue',
+        data: {
+          property: propertyName,
+          value: String(property.value.value),
+        },
+      });
+    }
+
+    // Check for string literals that are unitless numbers (e.g., width: '100')
+    if (property.value.type === AST_NODE_TYPES.Literal && typeof property.value.value === 'string') {
+      const stringValue = property.value.value.trim();
+
+      // Check if the string is a pure number (with optional negative sign and decimals)
+      // This regex matches: -10, 10, 10.5, -10.5, but not 10px, 10rem, etc.
+      const unitlessNumberRegex = /^-?\d+(\.\d+)?$/;
+
+      if (unitlessNumberRegex.test(stringValue)) {
+        // Allow '0' and '-0' without units
+        const numValue = parseFloat(stringValue);
+        if (numValue === 0 || numValue === -0) {
+          return;
+        }
+
+        // Report unitless string numeric value
+        ruleContext.report({
+          node: property.value,
+          messageId: 'noUnitlessValue',
+          data: {
+            property: propertyName,
+            value: stringValue,
+          },
+        });
+      }
+    }
+
+    // Check for unary expressions (e.g., -10)
+    if (property.value.type === AST_NODE_TYPES.UnaryExpression && property.value.operator === '-') {
+      if (
+        property.value.argument.type === AST_NODE_TYPES.Literal &&
+        typeof property.value.argument.value === 'number'
+      ) {
+        // Allow -0 without units
+        if (property.value.argument.value === 0) {
+          return;
+        }
+
+        // Report unitless numeric value
+        ruleContext.report({
+          node: property.value as unknown as Rule.Node,
+          messageId: 'noUnitlessValue',
+          data: {
+            property: propertyName,
+            value: `-${property.value.argument.value}`,
+          },
+        });
+      }
+    }
+
+    // Process nested objects (for complex selectors, etc.)
+    if (property.value.type === AST_NODE_TYPES.ObjectExpression) {
+      processUnitlessValueInStyleObject(ruleContext, property.value, options);
+    }
+  });
+};

src/css-rules/no-unitless-values/unitless-value-visitor-creator.ts

@@ -0,0 +1,85 @@
+import type { Rule } from 'eslint';
+import { AST_NODE_TYPES, TSESTree } from '@typescript-eslint/utils';
+import { processRecipeProperties } from '../shared-utils/recipe-property-processor.js';
+import { ReferenceTracker, createReferenceTrackingVisitor } from '../shared-utils/reference-tracker.js';
+import { processStyleNode } from '../shared-utils/style-node-processor.js';
+import { processUnitlessValueInStyleObject } from './unitless-value-processor.js';
+import type { NoUnitlessValuesOptions } from './unitless-value-processor.js';
+
+/**
+ * Creates ESLint rule visitors for detecting unitless numeric values in style-related function calls.
+ * Uses reference tracking to automatically detect vanilla-extract functions based on their import statements.
+ *
+ * @param context The ESLint rule context.
+ * @param options Rule options including allowed property names.
+ * @returns An object with visitor functions for the ESLint rule.
+ */
+export const createUnitlessValueVisitors = (
+  context: Rule.RuleContext,
+  options: NoUnitlessValuesOptions = {},
+): Rule.RuleListener => {
+  const tracker = new ReferenceTracker();
+  const trackingVisitor = createReferenceTrackingVisitor(tracker);
+
+  const processWithOptions = (ruleContext: Rule.RuleContext, node: TSESTree.ObjectExpression): void => {
+    processUnitlessValueInStyleObject(ruleContext, node, options);
+  };
+
+  return {
+    ...trackingVisitor,
+
+    CallExpression(node) {
+      if (node.callee.type !== AST_NODE_TYPES.Identifier) {
+        return;
+      }
+
+      const functionName = node.callee.name;
+
+      // Check if this function is tracked as a vanilla-extract function
+      if (!tracker.isTrackedFunction(functionName)) {
+        return;
+      }
+
+      const originalName = tracker.getOriginalName(functionName);
+      if (!originalName) {
+        return;
+      }
+
+      // Handle different function types based on their original imported name
+      switch (originalName) {
+        case 'fontFace':
+          if (node.arguments.length > 0 && node.arguments[0]?.type === AST_NODE_TYPES.ObjectExpression) {
+            processWithOptions(context, node.arguments[0] as TSESTree.ObjectExpression);
+          }
+          break;
+
+        case 'globalFontFace':
+          if (node.arguments.length > 1 && node.arguments[1]?.type === AST_NODE_TYPES.ObjectExpression) {
+            processWithOptions(context, node.arguments[1] as TSESTree.ObjectExpression);
+          }
+          break;
+
+        case 'style':
+        case 'styleVariants':
+        case 'keyframes':
+          if (node.arguments.length > 0) {
+            processStyleNode(context, node.arguments[0] as TSESTree.ObjectExpression, processWithOptions);
+          }
+          break;
+
+        case 'globalStyle':
+        case 'globalKeyframes':
+          if (node.arguments.length >= 2) {
+            processStyleNode(context, node.arguments[1] as TSESTree.ObjectExpression, processWithOptions);
+          }
+          break;
+
+        case 'recipe':
+          if (node.arguments.length > 0 && node.arguments[0]?.type === AST_NODE_TYPES.ObjectExpression) {
+            processRecipeProperties(context, node.arguments[0] as TSESTree.ObjectExpression, processWithOptions);
+          }
+          break;
+      }
+    },
+  };
+};

src/index.ts

@@ -4,6 +4,7 @@ import customOrderRule from './css-rules/custom-order/rule-definition.js';
 import noEmptyStyleBlocksRule from './css-rules/no-empty-blocks/rule-definition.js';
 import noPxUnitRule from './css-rules/no-px-unit/index.js';
 import noTrailingZeroRule from './css-rules/no-trailing-zero/rule-definition.js';
+import noUnitlessValuesRule from './css-rules/no-unitless-values/rule-definition.js';
 import noUnknownUnitRule from './css-rules/no-unknown-unit/rule-definition.js';
 import noZeroUnitRule from './css-rules/no-zero-unit/rule-definition.js';
 import preferLogicalPropertiesRule from './css-rules/prefer-logical-properties/index.js';
@@ -12,7 +13,7 @@ import preferThemeTokensRule from './css-rules/prefer-theme-tokens/index.js';
 const vanillaExtract = {
   meta: {
     name: '@antebudimir/eslint-plugin-vanilla-extract',
-    version: '1.15.1',
+    version: '1.16.0',
   },
   rules: {
     'alphabetical-order': alphabeticalOrderRule,
@@ -21,6 +22,7 @@ const vanillaExtract = {
     'no-empty-style-blocks': noEmptyStyleBlocksRule,
     'no-px-unit': noPxUnitRule,
     'no-trailing-zero': noTrailingZeroRule,
+    'no-unitless-values': noUnitlessValuesRule,
     'no-unknown-unit': noUnknownUnitRule,
     'no-zero-unit': noZeroUnitRule,
     'prefer-logical-properties': preferLogicalPropertiesRule,