参考资料：

http://gitbook.zhangjikai.com/

https://www.jianshu.com/p/5e91dbc67179

关于插件： 在需要添加插件的file的本地路径下新建book.json文件(和SUMMARY文件同级)，参考上面的资料在文件中添加相应的插件。

文字加底色

This text is {% em %}highlighted !{% endem %}

This text is {% em type="green" %}highlighted in green!{% endem %}

This text is {% em type="red" %}highlighted in red!{% endem %}

This text is {% em color="#ff0000" %}highlighted with a custom color!{% endem %}

This text is highlighted !

This text is highlighted in green!

This text is highlighted in red!

This text is highlighted with a custom color!