react 使用stylus，配置完无法自动转化成rem

[lyfcp]

react 使用stylus，配置完无法自动转化成rem，px还是px，没有转化
配置如下：
plugins: () => [
require('postcss-flexbugs-fixes'),
require('postcss-preset-env')({
autoprefixer: {
flexbox: 'no-2009',
},
stage: 3,
}),
// Adds PostCSS Normalize as the reset css with default options,
// so that it honors browserslist config in package.json
// which in turn let's users customize the target behavior as per their needs.
postcssNormalize(),
require('postcss-px2rem-exclude')({
remUnit: 37.5 ,
exclude:/node_modules/i
}),
],