---
description: 'Learn how to customize the look and feel of the components.'
navigation:
  badge:
    label: Todo
---

This module relies on Nuxt [App Config](https://nuxt.com/docs/guide/directory-structure/app-config#app-config-file) file to customize the look and feel of the components at runtime with HMR (hot-module-replacement).

## Colors

### Configuration

Components are based on a `primary` and a `gray` color. You can change them in your `app.config.ts`.

```ts [app.config.ts]
export default defineAppConfig({
  ui: {
    primary: 'green',
    gray: 'cool'
  }
})
```

::tip
Try to change the `primary` and `gray` colors by clicking on the :u-icon{name="i-heroicons-swatch-20-solid" class="w-4 h-4 align-middle text-primary-500 dark:text-primary-400"} button in the header.
::

As this module uses Tailwind CSS under the hood, you can use any of the [Tailwind CSS colors](https://tailwindcss.com/docs/customizing-colors#color-palette-reference) or your own custom colors. By default, the `primary` color is `green` and the `gray` color is `cool`.

When [using custom colors](https://tailwindcss.com/docs/customizing-colors#using-custom-colors) or [adding additional colors](https://tailwindcss.com/docs/customizing-colors#adding-additional-colors) through the `extend` key in your `tailwind.config.ts`, you'll need to make sure to define all the shades from `50` to `950` as most of them are used in the components config defined in [`ui.config/`](https://github.com/nuxt/ui/tree/dev/src/runtime/ui.config) directory. You can [generate your colors](https://tailwindcss.com/docs/customizing-colors#generating-colors) using tools such as https://uicolors.app/ for example.

```ts [tailwind.config.ts]
import type { Config } from 'tailwindcss'
import defaultTheme from 'tailwindcss/defaultTheme'

export default <Partial<Config>>{
  theme: {
    extend: {
      colors: {
        green: {
          50: '#EFFDF5',
          100: '#D9FBE8',
          200: '#B3F5D1',
          300: '#75EDAE',
          400: '#00DC82',
          500: '#00C16A',
          600: '#00A155',
          700: '#007F45',
          800: '#016538',
          900: '#0A5331',
          950: '#052e16'
        }
      }
    }
  }
}
```

### CSS Variables

To provide dynamic colors that can be changed at runtime, this module uses CSS variables. As Tailwind CSS already has a `gray` color, the module automatically renames it to `cool` to avoid conflicts (`coolGray` was renamed to `gray` when Tailwind CSS v3.0 was released).

Likewise, you can't define a `primary` color in your `tailwind.config.ts` as it would conflict with the `primary` color defined by the module.

::tip
We'd advise you to use those colors in your components and pages, e.g. `text-primary-500 dark:text-primary-400`, `bg-gray-100 dark:bg-gray-900`, etc. so your app automatically adapts when changing your `app.config.ts`.
::

The `primary` color also has a `DEFAULT` shade that changes based on the theme. It is `500` in light mode and `400` in dark mode. You can use as a shortcut in your components and pages, e.g. `text-primary`, `bg-primary`, `focus-visible:ring-primary`, etc.

## Components

### `app.config.ts`

You can find the config of each component in the [`ui.config/`](https://github.com/nuxt/ui/tree/dev/src/runtime/ui.config) directory. You can override those classes in your own `app.config.ts`.

```ts [app.config.ts]
export default defineAppConfig({
  ui: {
    container: {
      constrained: 'max-w-5xl'
    }
  }
})
```

Thanks to [tailwind-merge](https://github.com/dcastil/tailwind-merge), the `app.config.ts` is smartly merged with the default config. This means you don't have to rewrite everything.

You can change this behavior by setting `strategy` to `override` in your `app.config.ts`:

```ts [app.config.ts]
export default defineAppConfig({
  ui: {
    strategy: 'override',
    button: {
      color: {
        white: {
          solid: 'bg-white dark:bg-gray-900'
        }
      }
    }
  }
})
```

### `ui` prop

Each component has a `ui` prop that allows you to customize everything specifically.

```vue
<template>
  <UContainer :ui="{ constrained: 'max-w-2xl' }">
    <slot />
  </UContainer>
</template>
```

::tip
You can find the default classes for each component under the `Config` section.
::

Thanks to [tailwind-merge](https://github.com/dcastil/tailwind-merge), the `ui` prop is smartly merged with the config. This means you don't have to rewrite everything.

For example, the default preset of the `FormGroup` component looks like this:

```json
{
  "label": {
    "base": "block font-medium text-gray-700 dark:text-gray-200"
  }
}
```

To change the font of the `label`, you only need to write:

```vue
<UFormGroup name="email" label="Email" :ui="{ label: { base: 'font-semibold' } }" />
```

This will smartly replace the `font-medium` by `font-semibold` and prevent any class duplication and any class priority issue.

You can change this behavior by setting `strategy` to `override` inside the `ui` prop:

```vue
<UButton
  to="https://github.com/nuxt/ui"
  :ui="{
    strategy: 'override',
    color: {
      white: {
        solid: 'bg-white dark:bg-gray-900'
      }
    }
  }"
/>
```

### `class` attribute

You can also use the `class` attribute to add classes to the component.

```vue
<template>
  <UButton label="Button" class="rounded-full" />
</template>
```

Again, with [tailwind-merge](https://github.com/dcastil/tailwind-merge), this will smartly merge the classes with the `ui` prop and the config.

### Default values

Some component props like `size`, `color`, `variant`, etc. have a default value that you can override in your `app.config.ts`.

```ts [app.config.ts]
export default defineAppConfig({
  ui: {
    button: {
      default: {
        size: 'md',
        color: 'gray',
        variant: 'ghost'
      }
    }
  }
})
```

## Dark mode

All the components are styled with dark mode in mind.

Thanks to [Tailwind CSS dark mode](https://tailwindcss.com/docs/dark-mode#toggling-dark-mode-manually) class strategy and the [@nuxtjs/color-mode](https://github.com/nuxt-modules/color-mode) module, you literally have nothing to do.

You can disable dark mode by setting the `preference` to `light` instead of `system` in your `nuxt.config.ts`.

```ts [nuxt.config.ts]
export default defineNuxtConfig({
  colorMode: {
    preference: 'light'
  }
})
```

::tip
If you're stuck in dark mode even after changing this setting, you might need to remove the `nuxt-color-mode` entry from your browser's local storage.
::