docs: add --van-icon-font-family

packages/vant-icons/CHANGELOG.md

@@ -1,5 +1,9 @@
 ## Changelog
 
+## 3.0.2
+
+- compatible with the browser range of Vant 2
+
 ## 3.0.1
 
 - add `--van-icon-font-family` CSS var

packages/vant/src/icon/README.md

@@ -115,3 +115,11 @@ The component exports the following type definitions:
 ```ts
 import type { IconProps } from 'vant';
 ```
+
+### CSS Variables
+
+The component provides the following CSS variables, which can be used to customize styles. Please refer to [ConfigProvider component](#/en-US/config-provider).
+
+| Name                   | Default Value | Description |
+| ---------------------- | ------------- | ----------- |
+| --van-icon-font-family | _'van-icon'_  | -           |

packages/vant/src/icon/README.zh-CN.md

@@ -117,3 +117,13 @@ app.use(Icon);
 ```ts
 import type { IconProps } from 'vant';
 ```
+
+## 主题定制
+
+### 样式变量
+
+组件提供了下列 CSS 变量，可用于自定义样式，使用方法请参考 [ConfigProvider 组件](#/zh-CN/config-provider)。
+
+| 名称                   | 默认值       | 描述 |
+| ---------------------- | ------------ | ---- |
+| --van-icon-font-family | _'van-icon'_ | -    |