一、安装SCSS

npm install sass --save-dev
npm install sass-loader --save-dev  
npm install node-sass --save-dev
npm install vue-style-loader --sava-dev

二、添加主题文件theme.scss

@forward "element-plus/theme-chalk/src/common/var.scss" with (
  $colors: (
    "primary": (
      "base": #09c,
      "color": #fff,
    ),
  )
);
 
@use "element-plus/theme-chalk/src/index.scss" as *;

三、main.js引入

import './assets/css/theme.scss'

运行效果