doc: Update README.md

Author: jaywcjlove

README.md

@@ -58,8 +58,6 @@ type MarkdownPreviewProps = {
 
 This [`ReactMarkdownProps`](https://github.com/remarkjs/react-markdown/tree/02bac837bf141cdb8face360fb88be6fa33ab194#props) details. [Upgrade `react-markdown` v6](https://github.com/remarkjs/react-markdown/blob/15b4757082cf3f32a25eba0b8ea30baf751a8b40/changelog.md#600---2021-04-15)
 
-
-
 - `children` (`string`, default: `''`)\
     Markdown to parse
 - `className` (`string?`)\
@@ -103,13 +101,33 @@ This [`ReactMarkdownProps`](https://github.com/remarkjs/react-markdown/tree/02ba
     Same as `transformLinkUri` but for images
 - `components` (`Object.<string, Component>`, default: `{}`)\
     Object mapping tag names to React components
-- `remarkPlugins` (`Array.<Plugin>`, default: `[]`)\
+- `remarkPlugins`<!--rehype:style=color: red;background-color: #ffeb3b;--> (`Array.<Plugin>`, default: `[]`)\
     List of [remark plugins](https://github.com/remarkjs/remark/blob/main/doc/plugins.md#list-of-plugins) to use.
     See the next section for examples on how to pass options
-- `rehypePlugins` (`Array.<Plugin>`, default: `[]`)\
+- `rehypePlugins`<!--rehype:style=color: red;background-color: #ffeb3b;--> (`Array.<Plugin>`, default: `[]`)\
     List of [rehype plugins](https://github.com/rehypejs/rehype/blob/main/doc/plugins.md#list-of-plugins) to use.
     See the next section for examples on how to pass options
 
+## Markdown Features
+
+### Supports for CSS Style
+
+Use HTML comments [`<!--rehype:xxx-->`](https://github.com/jaywcjlove/rehype-attr)<!--rehype:style=color: red;--> to let Markdown support style customization.
+
+```markdown
+## Title
+<!--rehype:style=display: flex; height: 230px; align-items: center; justify-content: center; font-size: 38px;-->
+
+Markdown Supports **Style**<!--rehype:style=color: red;-->
+```
+
+### Support for [GFM footnotes](https://github.blog/changelog/2021-09-30-footnotes-now-supported-in-markdown-fields/)
+
+```markdown
+Here is a simple footnote[^1]. With some additional text after it.
+
+[^1]: My reference.
+```
 
 ## Development
 
@@ -119,9 +137,8 @@ Runs the project in development mode.
 # Step 1, run first,
 # listen to the component compile and output the .js file
 # listen for compilation output type .d.ts file
-npm run watch
 # listen to the component compile and output the .css file
-npm run css:watch
+npm run watch
 # Step 2, development mode, listen to compile preview website instance
 npm start
 ```
@@ -135,16 +152,15 @@ npm run build
 The build is minified and the filenames include the hashes.
 Your app is ready to be deployed!
 
-
 ### Related
 
 If you need more features-rich Markdown Editor, you can use [@uiwjs/react-markdown-editor](https://github.com/uiwjs/react-markdown-editor)
 
+- [@uiw/react-markdown-editor](https://github.com/uiwjs/react-markdown-editor): A markdown editor with preview, implemented with React.js and TypeScript.
+- [@uiw/react-md-editor](https://github.com/uiwjs/react-md-editor): A simple markdown editor with preview, implemented with React.js and TypeScript.
 - [@uiw/react-textarea-code-editor](https://github.com/uiwjs/react-textarea-code-editor): A simple code editor with syntax highlighting.
 - [@uiw/react-codemirror](https://github.com/uiwjs/react-codemirror): CodeMirror component for React. @codemirror
 - [@uiw/react-monacoeditor](https://github.com/jaywcjlove/react-monacoeditor): Monaco Editor component for React.
-- [@uiw/react-markdown-editor](https://github.com/uiwjs/react-markdown-editor): A markdown editor with preview, implemented with React.js and TypeScript.
-- [@uiw/react-md-editor](https://github.com/uiwjs/react-md-editor): A simple markdown editor with preview, implemented with React.js and TypeScript.
 
 ## License