---
group:
  title: Advanced
order: 1
title: CSS Compatible
---

Ant Design supports the last 2 versions of modern browsers. If you need to be compatible with legacy browsers, please perform downgrade processing according to actual needs:

## StyleProvider

Please ref [`@ant-design/cssinjs`](https://github.com/ant-design/cssinjs#styleprovider).

## Compatible adjustment

Ant Design default using CSS-in-JS with `:where` Selector to reduce priority to avoid user additional adjust style cost when updating. If you want to support old browser (or some other CSS framework selector priority conflict like TailwindCSS), you can use `@ant-design/cssinjs` to adjust this behavior (Please note keep version align with antd):

```tsx
import { StyleProvider } from '@ant-design/cssinjs';

// Config `hashPriority` to `high` instead of default `low`
// Which will remove `:where` wrapper
export default () => (
  <StyleProvider hashPriority="high">
    <MyApp />
  </StyleProvider>
);
```

It will turn `:where` to class selector:

```diff
--  :where(.css-bAMboO).ant-btn {
++  .css-bAMboO.ant-btn {
      color: #fff;
    }
```

Note: After turning off the `:where` downgrade, you may need to manually adjust the priority of some styles. Or you can **use PostCSS plugin** to raise application css selector priority. PostCSS provides many plugins can help on this. e.g:

- [postcss-scopify](https://www.npmjs.com/package/postcss-scopify)
- [postcss-increase-specificity](https://www.npmjs.com/package/postcss-increase-specificity)
- [postcss-add-root-selector](https://www.npmjs.com/package/postcss-add-root-selector)

Raise priority through plugin:

```diff
--  .my-btn {
++  #root .my-btn {
      background: red;
    }
```

## CSS Logical Properties

To unify LTR and RTL styles, Ant Design uses CSS logical properties. For example, the original `margin-left` is replaced by `margin-inline-start`, so that it is the starting position spacing under both LTR and RTL. If you need to be compatible with older browsers, you can configure `transformers` through the `StyleProvider` of `@ant-design/cssinjs`:

```tsx
import { StyleProvider, legacyLogicalPropertiesTransformer } from '@ant-design/cssinjs';

// `transformers` provides a way to transform CSS properties
export default () => (
  <StyleProvider transformers={[legacyLogicalPropertiesTransformer]}>
    <MyApp />
  </StyleProvider>
);
```

When toggled, styles will downgrade CSS logical properties:

```diff
.ant-modal-root {
-- inset: 0;
++ top: 0;
++ right: 0;
++ bottom: 0;
++ left: 0;
}
```

## Rem Adaptation

In responsive web development, there is a need for a convenient and flexible way to achieve page adaptation and responsive design. The `px2remTransformer` transformer can quickly and accurately convert pixel units in style sheets to rem units relative to the root element (HTML tag), enabling the implementation of adaptive and responsive layouts.

```tsx
import { StyleProvider, px2remTransformer } from '@ant-design/cssinjs';

const px2rem = px2remTransformer({
  rootValue: 32, // 32px = 1rem; @default 16
});

export default () => (
  <StyleProvider transformers={[px2rem]}>
    <MyApp />
  </StyleProvider>
);
```

The resulting transformed styles:

```diff
 .px2rem-box {
-  width: 400px;
+  width: 12.5rem;
   background-color: green;
-  font-size: 32px;
+  font-size: 1rem;
   border: 10PX solid #f0f;
 }

 @media only screen and (max-width: 600px) {
   .px2rem-box {
     background-color: red;
-    margin: 10px;
+    margin: 0.3125rem;
   }
 }
```

### Options

<!-- prettier-ignore -->
| Parameter | Description  | Type | Default |
| --- | --- | --- | --- |
| rootValue | Font size of the root element | `number` | 16 |
| precision | Decimal places for the converted value | `number` | 5 |
| mediaQuery | Whether to convert px in media queries | `boolean` | false |

For more details, please refer to: [px2rem.ts#Options](https://github.com/ant-design/cssinjs/blob/master/src/transformers/px2rem.ts)

## Shadow DOM Usage

Since `<style />` tag insertion is different from normal DOM in Shadow DOM scenario, you need to use `StyleProvider` of `@ant-design/cssinjs` to configure the `container` property to set the insertion position:

```tsx
import { StyleProvider } from '@ant-design/cssinjs';
import { createRoot } from 'react-dom/client';

const shadowRoot = someEle.attachShadow({ mode: 'open' });
const container = document.createElement('div');
shadowRoot.appendChild(container);
const root = createRoot(container);

root.render(
  <StyleProvider container={shadowRoot}>
    <MyApp />
  </StyleProvider>,
);
```