---
id: fast-foundation.designsystem.withdesigntokenroot
title: DesignSystem.withDesignTokenRoot() method
hide_title: true
---
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[@microsoft/fast-foundation](./fast-foundation.md) &gt; [DesignSystem](./fast-foundation.designsystem.md) &gt; [withDesignTokenRoot](./fast-foundation.designsystem.withdesigntokenroot.md)

## DesignSystem.withDesignTokenRoot() method

Overrides the  root, controlling where  default value CSS custom properties are emitted.

Providing `null` disables automatic DesignToken registration.

<b>Signature:</b>

```typescript
withDesignTokenRoot(root: HTMLElement | Document | null): DesignSystem;
```

## Parameters

|  Parameter | Type | Description |
|  --- | --- | --- |
|  root | HTMLElement \| Document \| null | the root to register |

<b>Returns:</b>

[DesignSystem](./fast-foundation.designsystem.md)
