Cannot build using postcss-csso

[hereticjsorg]

This is about Bulma.

Overview of the problem

This is about the Bulma CSS framework. I'm using Bulma version 1.0.1. My browser is: Chrome (latest). This is a Sass issue: I'm using version 1.77.6.

Description

I'm using Webpack to build my application (Heretic Web Framework) which is using Bulma (https://hereticjs.org/, https://demo.hereticjs.org/). It's using PostCSS and postcss-csso in order to use Bulma.

The error is happening here: utils/mixins.scss

@mixin container-from($name, $width) {
  @container #{$name} (min-width: #{$width}) {
    @content;
  }
}

@mixin container-until($name, $width) {
  @container #{$name} (max-width: #{$width - 1px}) {
    @content;
  }
}

Error message from Webpack output:

Module build failed (from ./node_modules/postcss-loader/dist/cjs.js):

  SyntaxError

  (392:2) from "postcss-csso" plugin: /Users/xtreme/Documents/GitHub/heretic/src/core/styles/bulma/utilities/mixins.scss ")" is expected

    390 | 
    391 | @mixin container-until($name, $width) {
  > 392 |   @container #{$name} (max-width: #{$width - 1px}) {
        |  ^
    393 |     @content;
    394 |   }

As a workaround, I fixed this as:

@mixin container-from($name, $width) {
  @content;
}

@mixin container-until($name, $width) {
  @content;
}

Steps to Reproduce

1. git clone --depth 1 --branch master https://github.com/hereticjsorg/heretic.git
2. npm run install-modules
3. npm run configure
4. Replace my workaround code by the original code at src/core/styles/bulma/utilities/mixins.scss
5. npm run build -- --dev

Expected behavior

No errors! ;-)

Actual behavior

Cannot build because of a syntax error.