Subtheming is not working - style.css is empty!

Exact same error I'm seeing.

Not sure where the bug needs to be fixed (Barrio itself maybe?), but I added:

$table-border-width: 3px;

to my variables.scss subtheme file and it fixed the issue for me.

I am also facing the same issue on fresh installation of Drupal 10.0.9 and Bootstrap Sass theme.

Here is the error I getting:

Error in plugin "sass"
Message:
    ..\..\contrib\bootstrap_barrio\scss\components\table.scss
Error: Undefined operation "2 * var(--bs-border-width)".
  ╷
8 │     border-bottom: (2 * $table-border-width) solid $table-border-color;      
  │                     ^^^^^^^^^^^^^^^^^^^^^^^
  ╵
  ..\..\contrib\bootstrap_barrio\scss\components\table.scss 8:21  @import        
  ..\..\contrib\bootstrap_barrio\scss\barrio.scss 34:9            @import        
  scss\import.scss 15:9                                           @import        
  scss\style.scss 7:9                                             root stylesheet

Adding $table-border-width variable in subtheme variables.scss fixes this issue. However, it should fixed at the barrio level.

Thanks hawkeye217! I can confirm that your solution also worked for me.

Thank you @hawkeye217 @rahul.rahangdale
It worked for me also so creating patch.

Created PR according Patch.

I have tested this in drupal version 10, bootstrap sass version 5.0.6, I have used
the proposed patch and it worked for me, really a great contribution.