---
title: Theming
description: Using CSS Variables and color utilities for theming.
---

You can choose between using CSS variables (recommended) or utility classes for theming.

## CSS Variables

```tsx /bg-background/ /text-foreground/
<div className="bg-background text-foreground" />
```

To use CSS variables for theming set `tailwind.cssVariables` to `true` in your `components.json` file.

```json {8} title="components.json"
{
  "style": "default",
  "rsc": true,
  "tailwind": {
    "config": "",
    "css": "app/globals.css",
    "baseColor": "neutral",
    "cssVariables": true
  },
  "aliases": {
    "components": "@/components",
    "utils": "@/lib/utils",
    "ui": "@/registry/new-york-v4/ui",
    "lib": "@/lib",
    "hooks": "@/hooks"
  },
  "iconLibrary": "lucide"
}
```

## Utility classes

```tsx /bg-zinc-950/ /text-zinc-50/ /dark:bg-white/ /dark:text-zinc-950/
<div className="bg-zinc-950 dark:bg-white" />
```

To use utility classes for theming set `tailwind.cssVariables` to `false` in your `components.json` file.

```json {8} title="components.json"
{
  "style": "default",
  "rsc": true,
  "tailwind": {
    "config": "",
    "css": "app/globals.css",
    "baseColor": "slate",
    "cssVariables": false
  },
  "aliases": {
    "components": "@/components",
    "utils": "@/lib/utils",
    "ui": "@/registry/new-york-v4/ui",
    "lib": "@/lib",
    "hooks": "@/hooks"
  },
  "iconLibrary": "lucide"
}
```

## Convention

We use a simple `background` and `foreground` convention for colors. The `background` variable is used for the background color of the component and the `foreground` variable is used for the text color.

<Callout className="mt-4">

The `background` suffix is omitted when the variable is used for the background color of the component.

</Callout>

Given the following CSS variables:

```css
--primary: oklch(0.205 0 0);
--primary-foreground: oklch(0.985 0 0);
```

The `background` color of the following component will be `var(--primary)` and the `foreground` color will be `var(--primary-foreground)`.

```tsx
<div className="bg-primary text-primary-foreground">Hello</div>
```

## List of variables

Here's the list of variables available for customization:

```css title="app/globals.css"
:root {
  --background: oklch(1 0 0);
  --foreground: oklch(0.145 0 0);
  --card: oklch(1 0 0);
  --card-foreground: oklch(0.145 0 0);
  --popover: oklch(1 0 0);
  --popover-foreground: oklch(0.145 0 0);
  --primary: oklch(0.205 0 0);
  --primary-foreground: oklch(0.985 0 0);
  --secondary: oklch(0.97 0 0);
  --secondary-foreground: oklch(0.205 0 0);
  --muted: oklch(0.97 0 0);
  --muted-foreground: oklch(0.556 0 0);
  --accent: oklch(0.97 0 0);
  --accent-foreground: oklch(0.205 0 0);
  --destructive: oklch(0.577 0.245 27.325);
  --destructive-foreground: oklch(0.577 0.245 27.325);
  --border: oklch(0.922 0 0);
  --input: oklch(0.922 0 0);
  --ring: oklch(0.708 0 0);
  --chart-1: oklch(0.646 0.222 41.116);
  --chart-2: oklch(0.6 0.118 184.704);
  --chart-3: oklch(0.398 0.07 227.392);
  --chart-4: oklch(0.828 0.189 84.429);
  --chart-5: oklch(0.769 0.188 70.08);
  --radius: 0.625rem;
  --sidebar: oklch(0.985 0 0);
  --sidebar-foreground: oklch(0.145 0 0);
  --sidebar-primary: oklch(0.205 0 0);
  --sidebar-primary-foreground: oklch(0.985 0 0);
  --sidebar-accent: oklch(0.97 0 0);
  --sidebar-accent-foreground: oklch(0.205 0 0);
  --sidebar-border: oklch(0.922 0 0);
  --sidebar-ring: oklch(0.708 0 0);
}

.dark {
  --background: oklch(0.145 0 0);
  --foreground: oklch(0.985 0 0);
  --card: oklch(0.145 0 0);
  --card-foreground: oklch(0.985 0 0);
  --popover: oklch(0.145 0 0);
  --popover-foreground: oklch(0.985 0 0);
  --primary: oklch(0.985 0 0);
  --primary-foreground: oklch(0.205 0 0);
  --secondary: oklch(0.269 0 0);
  --secondary-foreground: oklch(0.985 0 0);
  --muted: oklch(0.269 0 0);
  --muted-foreground: oklch(0.708 0 0);
  --accent: oklch(0.269 0 0);
  --accent-foreground: oklch(0.985 0 0);
  --destructive: oklch(0.396 0.141 25.723);
  --destructive-foreground: oklch(0.637 0.237 25.331);
  --border: oklch(0.269 0 0);
  --input: oklch(0.269 0 0);
  --ring: oklch(0.556 0 0);
  --chart-1: oklch(0.488 0.243 264.376);
  --chart-2: oklch(0.696 0.17 162.48);
  --chart-3: oklch(0.769 0.188 70.08);
  --chart-4: oklch(0.627 0.265 303.9);
  --chart-5: oklch(0.645 0.246 16.439);
  --sidebar: oklch(0.205 0 0);
  --sidebar-foreground: oklch(0.985 0 0);
  --sidebar-primary: oklch(0.488 0.243 264.376);
  --sidebar-primary-foreground: oklch(0.985 0 0);
  --sidebar-accent: oklch(0.269 0 0);
  --sidebar-accent-foreground: oklch(0.985 0 0);
  --sidebar-border: oklch(0.269 0 0);
  --sidebar-ring: oklch(0.439 0 0);
}
```

## Adding new colors

To add new colors, you need to add them to your CSS file and to your `tailwind.config.js` file.

```css title="app/globals.css"
:root {
  --warning: oklch(0.84 0.16 84);
  --warning-foreground: oklch(0.28 0.07 46);
}

.dark {
  --warning: oklch(0.41 0.11 46);
  --warning-foreground: oklch(0.99 0.02 95);
}

@theme inline {
  --color-warning: var(--warning);
  --color-warning-foreground: var(--warning-foreground);
}
```

You can now use the `warning` utility class in your components.

```tsx /bg-warning/ /text-warning-foreground/
<div className="bg-warning text-warning-foreground" />
```

## Other color formats

See the [Tailwind CSS documentation](https://tailwindcss.com/docs/colors) for more information on using colors in Tailwind CSS.