JisonLexerError: Lexical error on line 1: Unrecognized text.

[frederikhors]

From "postcss-simple-vars": "6.0.2" to "postcss-simple-vars": "6.0.3" (the only upgrade in my package.json) I get this error during build:

Unknown error from PostCSS plugin. Your current PostCSS version is 8.2.4, but cssnano uses 7.0.35. Perhaps this is the source of the error below.
[!] (plugin postcss) JisonLexerError: Lexical error on line 1: Unrecognized text.

  Erroneous area:
1: 100vh - $my-custom-var
^..........^

[sampullman]

There is a potential incompatibility with plugins using PostCSS < 8, you can try the workaround here: #94 , otherwise the best option is to pin 6.0.2 until cssnano is updated.