chore: add import css style instruction

Author: Peng Jie

README.md

@@ -50,6 +50,16 @@ const defaultOptions = {
 
 You can custom options for you want, just pass `options` as props. The configuration you can reference [here](https://github.com/rtfpessoa/diff2html#configuration). :mag_right:
 
+## Style
+
+Import css style make sure render correctly:
+
+```js
+import 'react-gh-like-diff/dist/css/diff2html.min.css';
+```
+
+You also can reference [examples](https://github.com/neighborhood999/react-gh-like-diff/blob/master/example/compare-markdown/src/App.js).
+
 ## Props
 
 ### past

example/compare-markdown/src/App.js

@@ -3,7 +3,7 @@ import { ReactGhLikeDiff } from 'react-gh-like-diff';
 import fetch from 'unfetch';
 import { TITLE, PAST, CURRENT } from './constants';
 import './App.css';
-import 'react-gh-like-diff/lib/diff2html.min.css';
+import 'react-gh-like-diff/dist/css/diff2html.min.css';
 
 class App extends Component {
   state = {