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# tools.lightningcssLoader

- **Type:** `Rspack.LightningcssLoaderOptions | Function | boolean`
- **Default:**

```ts
const defaultOptions = {
  errorRecovery: true,
  // use current project's browserslist config
  targets: browserslist,
  // minify is enabled when output.injectStyles is true and in production mode
  minify: config.mode === 'production' && config.output.injectStyles,
};
```

You can set the options for [builtin:lightningcss-loader](https://rspack.rs/guide/features/builtin-lightningcss-loader) through `tools.lightningcssLoader`.

## Object type

When `tools.lightningcssLoader` is an object, it will be merged with the default configuration using `Object.assign`.

For example, you can disable the addition of vendor prefixes through `tools.lightningcssLoader.exclude`. In this case, you can use PostCSS's autoprefixer plugin to add vendor prefixes.

```ts title="rsbuild.config.ts"
export default {
  tools: {
    lightningcssLoader: {
      exclude: {
        vendorPrefixes: true,
      },
    },
  },
};
```

## Function type

When `tools.lightningcssLoader` is a function, the default options will be passed in as the first parameter. You can directly modify this object or return a new object as the final options to be used. For example:

```ts title="rsbuild.config.ts"
export default {
  tools: {
    lightningcssLoader: (config) => {
      config.exclude = {
        vendorPrefixes: true,
      };
      return config;
    },
  },
};
```

## Disable loader

Set `tools.lightningcssLoader` to `false` to disable the built-in `lightningcss-loader` in Rsbuild:

```ts title="rsbuild.config.ts"
export default {
  tools: {
    lightningcssLoader: false,
  },
};
```

:::tip
Setting `tools.lightningcssLoader` to `false` only disables the `lightningcss-loader`. If you need to disable the full functionality of Lightning CSS, refer to [Disabling Lightning CSS](/guide/styling/css-usage.md#disabling-lightning-css).
:::