uniappx里面没法使用rem吗？运行到安装报错

margin: 0 0.4rem 0.4rem 0;
11:08:06.542 ​[plugin:uni:app-uvue-css] ERROR: property value 0.4rem is not supported for margin-right (supported values are: number|pixel|percent|auto)​
11:08:06.542 ​