提示：
DEPRECATION WARNING: Using / for division is deprecated and will be removed in Dart Sass 2.0.0.
Recommendation: math.div($--tooltip-arrow-size, 2)
More info and automated migrator: https://sass-lang.com/d/slash-div
╷
70 │ margin-bottom: #{$--tooltip-arrow-size / 2};
│ ^^^^^^^^^^^^^^^^^^^^^^^^^
╵
node_modules/element-ui/packages/theme-chalk/src/popper.scss 70:22 @content
node_modules/element-ui/packages/theme-chalk/src/mixins/mixins.scss 74:5 b()
node_modules/element-ui/packages/theme-chalk/src/popper.scss 4:1 @import
node_modules/element-ui/packages/theme-chalk/src/select-dropdown.scss 3:9 @import
node_modules/element-ui/packages/theme-chalk/src/select.scss 4:9 @import
node_modules/element-ui/packages/theme-chalk/src/pagination.scss 4:9 @import
node_modules/element-ui/packages/theme-chalk/src/index.scss 2:9 @import
stdin 2:9 root stylesheet
报错的原因是除法有精度问题，所以被禁用了。
这时候，只要把 / 2 的操作改成 ` *0.5` 就可以了。