<===> input.scss
& {}

<===> error
Error: Base-level rules cannot contain the parent-selector-referencing character '&'.
        on line 1 of input.scss
  Use --trace for backtrace.

<===> error-libsass
Error: Top-level selectors may not contain the parent selector "&".
        on line 1 of input.scss
>> & {}

<===> error-dart-sass
Error: Top-level selectors may not contain the parent selector "&".
  ,
1 | & {}
  | ^^
  '
  input.scss 1:1  root stylesheet