Steps to reproduce the issue

Follow the instructions to clone joomla-cms on localhost.
Checkout: git checkout 5.0-dev
When building or rebuilding after testing, npm run build:css
I get a sequence of deprecation warnings. On a separate clone with 4.3-dev checked out there are no warnings.
I realise it may be something to do with my setup. I actually downgraded node fro v20 to 418 (stable) with no effect. The build goes to completion but I worry my tests my be invalid. Example:

Deprecation Warning: Passing percentage units to the global abs() function is deprecated.
In the future, this will emit a CSS abs() function to be resolved by the browser.
To preserve current behavior: math.abs(100%)
To emit a CSS abs() now: abs(#{100%})
More info: https://sass-lang.com/d/abs-percent

  ╷
1 │ ┌ // This file is a placeholder for the rtl template
2 │ └ @import "template";
  ╵
    build/media_source/templates/site/cassiopeia/scss/template-rtl.scss 1:1  divide()
    media/vendor/bootstrap/scss/mixins/_grid.scss 59:12                      row-cols()
    media/vendor/bootstrap/scss/mixins/_grid.scss 85:13                      @content
    media/vendor/bootstrap/scss/mixins/_breakpoints.scss 68:5                media-breakpoint-up()
    media/vendor/bootstrap/scss/mixins/_grid.scss 72:5                       make-grid-columns()
    media/vendor/bootstrap/scss/_grid.scss 38:3                              @import
    media/vendor/bootstrap/scss/bootstrap.scss 20:9                          @import
    build/media_source/templates/site/cassiopeia/scss/template.scss 14:9     @import
    build/media_source/templates/site/cassiopeia/scss/template-rtl.scss 2:9  root stylesheet

Expected result

Actual result

System information (as much as possible)

Additional comments