---
title: Styling & Theming
description: Complete guide to styling changes and theming system migration from HeroUI v2 to v3
---

<Callout type="info">
  This guide covers all styling-related changes between HeroUI v2 and v3, including utility classes, component styles, theme system architecture, and visual differences. For component-specific API changes, see individual component migration guides.
</Callout>

**Note:** The `classNames` prop has been replaced with `className` prop in v3. All components now use the standard React `className` prop instead of the `classNames` object prop from v2.

## Overview

HeroUI v3 introduces significant changes to the styling system:

- **CSS-First Architecture**: Replaces Tailwind plugin with pure CSS files
- **Standard Tailwind Utilities**: Custom utilities replaced with standard Tailwind classes
- **CSS Variables**: New CSS variable naming and structure
- **Component Styles**: Updated default sizes, spacing, and visual appearance
- **No Plugin Required**: Removed dependency on Tailwind plugin configuration
- **Color System Overhaul**: Semantic colors reorganized (`primary` → `accent`, `secondary` removed, numbered scales removed)
- **Content Colors Removed**: `content1-4` replaced with `surface` and `overlay` system

## Quick Reference

### Utility Classes Mapping

| v2 Utility | v3 Equivalent | Notes |
|-----------|--------------|-------|
| `text-tiny` | `text-xs` | Font size: 0.75rem → 0.75rem (same) |
| `text-small` | `text-sm` | Font size: 0.875rem → 0.875rem (same) |
| `text-medium` | `text-base` | Font size: 1rem → 1rem (same) |
| `text-large` | `text-lg` | Font size: 1.125rem → 1.125rem (same) |
| `rounded-small` | `rounded-sm` | Border radius: 8px → 4px (different) |
| `rounded-medium` | `rounded-md` | Border radius: 12px → 6px (different) |
| `rounded-large` | `rounded-lg` | Border radius: 14px → 8px (different) |
| `border-small` | `border` | Border width: 1px → 1px (use standard Tailwind) |
| `border-medium` | `border-2` | Border width: 2px → 2px (use standard Tailwind) |
| `border-large` | `border-[3px]` | Border width: 3px → 3px (use arbitrary value) |
| `bg-content1` | `bg-surface` or `bg-overlay` | Content color removed, use surface/overlay |
| `bg-content2` | `bg-surface-secondary` | Content color removed, use surface level |
| `bg-primary` | `bg-accent` | Primary renamed to accent |
| `bg-secondary` | `bg-default` | Secondary color removed, use default |
| `bg-primary-50` | `bg-accent-soft` | Numbered scales removed |
| `bg-primary-100` | `bg-accent-soft` | Numbered scales removed |
| `text-primary-600` | `text-accent` | Numbered scales removed |
| `.transition-background` | Standard CSS transitions | Removed utility |
| `.transition-colors-opacity` | Standard CSS transitions | Removed utility |

## Utility Classes Migration

### Text Utilities

HeroUI v2 provided custom text size utilities that mapped to CSS variables. v3 uses standard Tailwind text size classes.

**v2 Text Utilities:**

```tsx
// v2 - Custom utilities with CSS variables
<div className="text-tiny">Tiny text</div>
<div className="text-small">Small text</div>
<div className="text-medium">Medium text</div>
<div className="text-large">Large text</div>
```

**v3 Text Utilities:**

```tsx
// v3 - Standard Tailwind classes
<div className="text-xs">Tiny text</div>
<div className="text-sm">Small text</div>
<div className="text-base">Medium text</div>
<div className="text-lg">Large text</div>
```

**Mapping Details:**

| v2 Class | Font Size | Line Height | v3 Class | Font Size | Line Height |
|----------|-----------|-------------|----------|-----------|-------------|
| `text-tiny` | 0.75rem (12px) | 1rem (16px) | `text-xs` | 0.75rem (12px) | 1rem (16px) |
| `text-small` | 0.875rem (14px) | 1.25rem (20px) | `text-sm` | 0.875rem (14px) | 1.25rem (20px) |
| `text-medium` | 1rem (16px) | 1.5rem (24px) | `text-base` | 1rem (16px) | 1.5rem (24px) |
| `text-large` | 1.125rem (18px) | 1.75rem (28px) | `text-lg` | 1.125rem (18px) | 1.75rem (28px) |

### Border Radius Utilities

v2 used custom border radius utilities (`rounded-small`, `rounded-medium`, `rounded-large`) that mapped to CSS variables. v3 uses standard Tailwind border radius classes, but the actual values differ.

**v2 Border Radius:**

```tsx
// v2 - Custom utilities
<div className="rounded-small">Small radius</div>
<div className="rounded-medium">Medium radius</div>
<div className="rounded-large">Large radius</div>
```

**v3 Border Radius:**

```tsx
// v3 - Standard Tailwind classes
<div className="rounded-sm">Small radius</div>
<div className="rounded-md">Medium radius</div>
<div className="rounded-lg">Large radius</div>
```

**Value Comparison:**

| v2 Class | v2 Value | v3 Class | v3 Value | Difference |
|----------|----------|----------|----------|------------|
| `rounded-small` | 8px (0.5rem) | `rounded-sm` | 4px (0.25rem) | Smaller |
| `rounded-medium` | 12px (0.75rem) | `rounded-md` | 6px (0.375rem) | Smaller |
| `rounded-large` | 14px (0.875rem) | `rounded-lg` | 8px (0.5rem) | Smaller |

**Note:** v3 uses smaller default border radius values. If you need the exact v2 values, use arbitrary values:

```tsx
// Match v2 rounded-small (8px)
<div className="rounded-[8px]">Custom radius</div>

// Match v2 rounded-medium (12px)
<div className="rounded-[12px]">Custom radius</div>

// Match v2 rounded-large (14px)
<div className="rounded-[14px]">Custom radius</div>
```

### Border Width Utilities

v2 provided custom border width utilities (`border-small`, `border-medium`, `border-large`). v3 uses standard Tailwind border width classes.

**v2 Border Width:**

```tsx
// v2 - Custom utilities
<div className="border-small border-default">1px border</div>
<div className="border-medium border-accent">2px border</div>
<div className="border-large border-danger">3px border</div>
```

**v3 Border Width:**

```tsx
// v3 - Standard Tailwind classes
<div className="border border-default">1px border</div>
<div className="border-2 border-accent">2px border</div>
<div className="border-[3px] border-danger">3px border</div>
```

**Mapping:**

| v2 Class | Width | v3 Class | Width |
|----------|-------|----------|-------|
| `border-small` | 1px | `border` | 1px |
| `border-medium` | 2px | `border-2` | 2px |
| `border-large` | 3px | `border-[3px]` | 3px (arbitrary) |

### Transition Utilities

v2 provided custom transition utilities for common animation patterns with a default duration of 250ms. v3 removes these utilities in favor of standard Tailwind `transition-*` utilities, where you specify which properties to transition.

**v2 Transition Utilities:**

v2 provided custom transition utilities with a default duration of 250ms and `ease` timing function. The following table shows which CSS properties each utility transitions:

| v2 Utility | Transition Properties |
|-----------|----------------------|
| `.transition-background` | `background` |
| `.transition-colors-opacity` | `color, background-color, border-color, text-decoration-color, fill, stroke, opacity` |
| `.transition-width` | `width` |
| `.transition-height` | `height` |
| `.transition-size` | `width, height` |
| `.transition-left` | `left` |
| `.transition-transform-opacity` | `transform, scale, opacity rotate` |
| `.transition-transform-background` | `transform, scale, background` |
| `.transition-transform-colors` | `transform, scale, color, background, background-color, border-color, text-decoration-color, fill, stroke` |
| `.transition-transform-colors-opacity` | `transform, scale, color, background, background-color, border-color, text-decoration-color, fill, stroke, opacity` |

**Note:** These utilities are no longer available in v3. Use Tailwind's standard `transition-*` utilities to specify which properties to transition.

### Other Utilities

**Scrollbar Utilities:**

v2 provided `.scrollbar-hide` and `.scrollbar-default` utilities. v3 now exposes standards-only scrollbar utilities from `@heroui/styles`: `scrollbar`, `scrollbar-thin`, `scrollbar-default`, and `scrollbar-none`. Use `data-scrollbar="thin"`, `data-scrollbar="default"`, or `data-scrollbar="none"` on an ancestor for subtree-level control.

**Animation Utilities:**

v2 provided spinner animation utilities (`.spinner-bar-animation`, `.spinner-dot-animation`, etc.). These are handled internally by v3 components and are not exposed as utilities.

**Custom Utilities:**

v2 included utilities like:
- `.leading-inherit` → Use `leading-[inherit]`
- `.tap-highlight-transparent` → Use `[-webkit-tap-highlight-color:transparent]`
- `.input-search-cancel-button-none` → Use custom CSS if needed

## Theme System Architecture

### v2: Plugin-Based System

v2 used a Tailwind CSS plugin that:

1. **Generated Utilities**: Created custom utility classes via JavaScript
2. **CSS Variables**: Injected CSS variables through the plugin
3. **Theme Configuration**: Required configuration in `tailwind.config.js`
4. **Runtime Generation**: Utilities generated at build time

**v2 Configuration:**

```js
// tailwind.config.js
const {heroui} = require("@heroui/react");

module.exports = {
  plugins: [
    heroui({
      layout: {
        fontSize: {
          tiny: "0.75rem",
          small: "0.875rem",
          medium: "1rem",
          large: "1.125rem",
        },
        radius: {
          small: "8px",
          medium: "12px",
          large: "14px",
        },
      },
      themes: {
        light: {
          colors: {
            primary: {
              // color definitions
            },
          },
        },
      },
    }),
  ],
};
```

### v3: CSS-First System

v3 uses a pure CSS approach:

1. **CSS Files**: Styles defined in CSS files (`packages/styles/`)
2. **CSS Variables**: Variables defined in CSS, not generated
3. **No Plugin**: No Tailwind plugin required
4. **Import-Based**: Styles imported via CSS imports

**v3 Configuration:**

```css
/* globals.css */
@import "tailwindcss";
@import "@heroui/styles";
```

**No Tailwind Config Required:**

If you only use HeroUI, you can remove `tailwind.config.js` entirely. If you have custom Tailwind config, keep it but remove the HeroUI plugin.

### Architecture Comparison

| Aspect | v2 | v3 |
|--------|----|----|
| **Styling Method** | Tailwind plugin (JavaScript) | CSS files |
| **Utility Generation** | Runtime via plugin | Pre-defined CSS |
| **CSS Variables** | Generated by plugin | Defined in CSS |
| **Configuration** | `tailwind.config.js` | CSS imports |
| **Customization** | Plugin config | CSS variable overrides |
| **Build Dependency** | Requires plugin | No plugin needed |

## CSS Variables & Design Tokens

### Variable Naming Changes

v2 used the pattern `--heroui-{property}-{scale}` while v3 uses `--{property}` or `--color-{property}`.

**v2 CSS Variables:**

```css
--heroui-font-size-tiny: 0.75rem;
--heroui-font-size-small: 0.875rem;
--heroui-radius-small: 8px;
--heroui-radius-medium: 12px;
--heroui-border-width-medium: 2px;
--heroui-disabled-opacity: 0.5;
```

**v3 CSS Variables:**

```css
/* Typography - handled by Tailwind */
/* No custom font-size variables */

/* Radius */
--radius-xs: calc(var(--radius) * 0.25);
--radius-sm: calc(var(--radius) * 0.5);
--radius-md: calc(var(--radius) * 0.75);
--radius-lg: calc(var(--radius) * 1);
--radius-xl: calc(var(--radius) * 1.5);

/* Colors */
--color-background: var(--background);
--color-foreground: var(--foreground);
--color-accent: var(--accent);
--color-muted: var(--muted);

/* Opacity */
--disabled-opacity: 0.5;
```

### Color System Changes

**v2 Color Structure:**

```css
--heroui-primary: 210 100% 50%;
--heroui-primary-50: 210 100% 95%;
--heroui-primary-100: 210 100% 90%;
/* ... more shades ... */
```

**v3 Color Structure:**

```css
--accent: oklch(0.6204 0.195 253.83);
--accent-foreground: var(--snow);
--accent-hover: color-mix(in oklab, var(--accent) 90%, var(--accent-foreground) 10%);
```

**Key Differences:**

1. **Color Format**: v2 used HSL, v3 uses OKLCH
2. **Naming**: v2 used numbered shades (50-900), v3 uses semantic names
3. **Calculated Colors**: v3 uses `color-mix()` for hover states
4. **Foreground Colors**: v3 explicitly defines foreground colors
5. **Primary → Accent**: `primary` color renamed to `accent`
6. **Secondary Color Removed**: `secondary` semantic color removed (was purple in v2)
7. **Numbered Scales Removed**: Color scales like `primary-50`, `primary-100`, etc. no longer exist

### Primary → Accent Rename

v2 used `primary` as the main brand color. v3 renamed it to `accent` for better semantic clarity.

**v2 Primary Color:**

```tsx
// v2 - Primary color with numbered scales
<Button color="primary">Primary Button</Button>
<div className="bg-primary">Primary background</div>
<div className="bg-primary-50">Light primary</div>
<div className="bg-primary-100">Lighter primary</div>
<div className="text-primary-600">Primary text</div>
```

**v3 Accent Color:**

```tsx
// v3 - Accent color (no numbered scales)
<Button variant="primary">Primary Button</Button>
<div className="bg-accent">Accent background</div>
<div className="bg-accent-soft">Soft accent</div>
<div className="text-accent">Accent text</div>
```

**Migration:**

| v2 Class | v3 Equivalent | Notes |
|----------|---------------|-------|
| `bg-primary` | `bg-accent` | Base accent color |
| `text-primary` | `text-accent` | Accent text color |
| `bg-primary-50` | `bg-accent-soft` | Light accent variant |
| `bg-primary-100` | `bg-accent-soft` | Light accent variant |
| `bg-primary-500` | `bg-accent` | Base accent color |
| `text-primary-600` | `text-accent` | Accent text color |
| `border-accent` | `border-accent` | Accent border |

**Note:** v3 doesn't have numbered color scales (`-50`, `-100`, `-200`, etc.). Use semantic variants like `-soft`, `-hover`, or custom Tailwind classes.

### Secondary Color Removed

v2 provided a `secondary` semantic color (purple). This has been removed in v3. Component variants named "secondary" now use different colors.

**v2 Secondary Color:**

```tsx
// v2 - Secondary as a semantic color (purple)
<Button color="secondary">Secondary Button</Button>
<div className="bg-secondary">Secondary background</div>
<div className="bg-secondary-50">Light secondary</div>
<div className="text-secondary-600">Secondary text</div>
```

**v3 Secondary Variant:**

```tsx
// v3 - Secondary is a variant, not a color
<Button variant="secondary">Secondary Button</Button>
<div className="bg-default">Default background (used by secondary variant)</div>
<div className="text-accent">Accent text</div>
```

**Migration:**

| v2 Class | v3 Equivalent | Notes |
|----------|---------------|-------|
| `bg-secondary` | `bg-default` | Secondary variant uses default color |
| `text-secondary` | `text-accent` | Use accent for emphasis |
| `bg-secondary-50` | `bg-default` | Use default color |
| `border-secondary` | `border-accent` | Use accent border |

**Note:** In v3, "secondary" refers to a component variant style (like `button--secondary`), not a color token. The secondary variant typically uses `bg-default` and `text-accent-soft-foreground`.

### Numbered Color Scales Removed

v2 provided numbered color scales (50-900) for all semantic colors. v3 removed these in favor of semantic variants and calculated colors.

**v2 Numbered Scales:**

```tsx
// v2 - Numbered color scales
<div className="bg-primary-50">Lightest</div>
<div className="bg-primary-100">Lighter</div>
<div className="bg-primary-200">Light</div>
<div className="bg-primary-500">Base</div>
<div className="bg-primary-600">Dark</div>
<div className="bg-primary-900">Darkest</div>
```

**v3 Semantic Variants:**

```tsx
// v3 - Semantic variants and calculated colors
<div className="bg-accent-soft">Soft variant</div>
<div className="bg-accent">Base color</div>
<div className="bg-accent-hover">Hover state</div>
```

**Migration:**

- **Light shades** (`-50`, `-100`, `-200`): Use `-soft` variants or custom Tailwind opacity classes
- **Base color** (`-500`): Use base color name (`bg-accent`, `bg-danger`, etc.)
- **Dark shades** (`-600`, `-700`, `-800`, `-900`): Use hover variants or custom Tailwind classes

### Content Colors Removed

v2 provided `content1`, `content2`, `content3`, and `content4` colors for layered backgrounds. These have been removed in v3 and replaced with semantic surface colors.

**v2 Content Colors:**

```tsx
// v2 - Content colors for layered backgrounds
<div className="bg-content1">Base content</div>
<div className="bg-content2">Secondary content</div>
<div className="bg-content3">Tertiary content</div>
<div className="bg-content4">Quaternary content</div>
```

**v3 Surface Colors:**

```tsx
// v3 - Surface colors for non-overlay components
<div className="bg-surface">Base surface</div>
<div className="bg-surface-secondary">Secondary surface</div>
<div className="bg-surface-tertiary">Tertiary surface</div>
<div className="bg-surface-quaternary">Quaternary surface</div>

// v3 - Overlay colors for floating components
<div className="bg-overlay">Overlay (tooltips, popovers, modals)</div>
```

**Migration Mapping:**

| v2 Class | v3 Equivalent | Usage |
|----------|---------------|-------|
| `bg-content1` | `bg-surface` | Non-overlay components (cards, accordions) |
| `bg-content1` | `bg-overlay` | Floating components (tooltips, popovers, modals) |
| `bg-content2` | `bg-surface-secondary` | Secondary surface level |
| `bg-content3` | `bg-surface-tertiary` | Tertiary surface level |
| `bg-content4` | `bg-surface-quaternary` | Quaternary surface level |

**Key Changes:**

1. **Semantic Naming**: `content1-4` replaced with `surface` and `overlay` for clearer semantics
2. **Component-Specific**: Use `bg-surface` for page-level components, `bg-overlay` for floating components
3. **Auto-Calculated**: Surface levels (`secondary`, `tertiary`, `quaternary`) are automatically calculated from the base `surface` color using `color-mix()`

### Spacing & Layout Tokens

**v2 Layout Tokens:**

```css
--heroui-divider-weight: 1px;
--heroui-disabled-opacity: 0.5;
--heroui-hover-opacity: 0.8;
```

**v3 Layout Tokens:**

```css
--border-width: 0px;
--field-border-width: var(--border-width);
--disabled-opacity: 0.5;
--cursor-interactive: pointer;
--cursor-disabled: not-allowed;
--radius: 0.5rem;
--field-radius: calc(var(--radius) * 1.5);
```

### Shadow Tokens

**v2 Shadows:**

```css
--heroui-box-shadow-small: 0px 0px 5px 0px rgb(0 0 0 / 0.02), ...;
--heroui-box-shadow-medium: 0px 0px 15px 0px rgb(0 0 0 / 0.03), ...;
--heroui-box-shadow-large: 0px 0px 30px 0px rgb(0 0 0 / 0.04), ...;
```

**v3 Shadows:**

```css
--surface-shadow: 0 2px 4px 0 rgba(0, 0, 0, 0.04), ...;
--overlay-shadow: 0 4px 16px 0 rgba(24, 24, 27, 0.08), ...;
--field-shadow: 0 2px 4px 0 rgba(0, 0, 0, 0.04), ...;
```

**Key Changes:**

1. **Semantic Naming**: v3 uses semantic names (`surface-shadow`, `overlay-shadow`) instead of size-based names
2. **Component-Specific**: Shadows are tied to component types (surface, overlay, field)
3. **Dark Mode**: Dark mode shadows are transparent in v3

## Visual Differences

### Alignment Changes

**Button Alignment:**

- v2: Icons and text aligned with `items-center justify-center`
- v3: Same alignment, but with responsive height adjustments

**Input Alignment:**

- v2: Text aligned with `text-left`
- v3: Same alignment, but padding adjustments may affect visual balance

### Spacing Changes

**Component Padding:**

Most components have increased padding in v3:

- **Card**: 12px → 16px
- **Button**: Similar padding, but responsive heights
- **Input**: Added vertical padding (`py-2`)

**Gap Spacing:**

v3 uses more consistent gap spacing:

- **Card**: `gap-3` between header, content, footer
- **Button**: `gap-2` between icon and text
- **Chip**: `gap-1.5` between elements

### Size Changes

**Button Heights:**

- **Small**: 32px → 36px (mobile) / 32px (desktop)
- **Medium**: 40px → 40px (mobile) / 36px (desktop)
- **Large**: 48px → 44px (mobile) / 40px (desktop)

**Input Heights:**

- **Medium**: 40px → 36px (default, only size available)

### Border Radius Changes

**Default Radius:**

- v2: Components used `rounded-medium` (12px) by default
- v3: Components use larger radius values:
  - Button: `rounded-3xl` (24px)
  - Card: `rounded-3xl` (24px)
  - Chip: `rounded-2xl` (16px)
  - Input: `rounded-field` (typically 12-16px)

### Color Appearance Changes

**Color System:**

- v2: HSL color format
- v3: OKLCH color format (more perceptually uniform)

**Default Colors:**

- v2: `primary`, `secondary`, `success`, `warning`, `danger`
- v3: `accent` (replaces `primary`), `success`, `warning`, `danger`

**Muted Colors:**

- v2: `foreground-400`, `foreground-500` for muted text
- v3: `muted` color token for muted text

## Migration Examples

### Utility Class Migration

**Example: Text Utilities**

<Tabs items={["v2", "v3"]}>
  <Tab value="v2">
    ```tsx
    <div>
      <h1 className="text-large font-bold">Title</h1>
      <p className="text-small text-foreground-400">Description</p>
      <span className="text-tiny text-foreground-500">Helper</span>
    </div>
    ```
  </Tab>
  <Tab value="v3">
    ```tsx
    <div>
      <h1 className="text-lg font-bold">Title</h1>
      <p className="text-sm text-muted">Description</p>
      <span className="text-xs text-muted">Helper</span>
    </div>
    ```
  </Tab>
</Tabs>

### Border Radius Migration

**Example: Matching v2 Radius Values**

<Tabs items={["v2", "v3"]}>
  <Tab value="v2">
    ```tsx
    <Card radius="md">
      <CardBody>Content</CardBody>
    </Card>
    ```
  </Tab>
  <Tab value="v3">
    ```tsx
    {/* Option 1: Use standard Tailwind (smaller radius) */}
    <Card className="rounded-md">
      <Card.Content>Content</Card.Content>
    </Card>

    {/* Option 2: Match exact v2 value (12px) */}
    <Card className="rounded-[12px]">
      <Card.Content>Content</Card.Content>
    </Card>
    ```
  </Tab>
</Tabs>

### Theme Customization Migration

**Example: Custom Colors**

<Tabs items={["v2", "v3"]}>
  <Tab value="v2">
    ```js
    // tailwind.config.js
    const {heroui} = require("@heroui/react");

    module.exports = {
      plugins: [
        heroui({
          themes: {
            light: {
              colors: {
                primary: {
                  DEFAULT: "#006FEE",
                  50: "#E6F1FE",
                  // ... more shades
                },
              },
            },
          },
        }),
      ],
    };
    ```
  </Tab>
  <Tab value="v3">
    ```css
    /* globals.css */
    @import "tailwindcss";
    @import "@heroui/styles";

    :root {
      --accent: oklch(0.6204 0.195 253.83);
      --accent-foreground: oklch(0.9911 0 0);
    }
    ```
  </Tab>
</Tabs>

## Best Practices

1. **Use Standard Tailwind**: Prefer standard Tailwind utilities over custom ones
2. **Match v2 Values**: If exact v2 appearance is needed, use arbitrary values
3. **Test Responsively**: v3 has responsive sizing - test on multiple screen sizes
4. **Update CSS Variables**: If customizing, update CSS variables instead of Tailwind config
5. **Check Component Docs**: Refer to individual component migration guides for API changes

## Related Guides

- [Main Migration Guide](/docs/react/migration)
- [Theming Documentation](/docs/react/getting-started/handbook/theming)
- [Styling Guide](/docs/react/getting-started/handbook/styling)
