sass 吧，还能用命令行动态监听变化生成 css，其他两个配起来太麻烦

https://doc.webpack-china.org/loaders/less-loader

//修改 webpack 配置文件
// webpack.config.js
module.exports = {
...
module: {
rules: [{
test: /\.less$/,
use: [{
loader: "style-loader" // creates style nodes from JS strings
}, {
loader: "css-loader" // translates CSS into CommonJS
}, {
loader: "less-loader" // compiles Less to CSS
}]
}]
}
};