Deprecation Warnings: Sass @import and Color/Math Functions in Bootstrap 5.3.7

[hanifshahy]

Prerequisites

• I have searched for duplicate or closed feature requests
• I have read the contributing guidelines

Proposal

I am using Bootstrap 5.3.7 with Dart Sass 1.89.1 and am seeing many deprecation warnings during build, such as:

@import rules are deprecated and will be removed in Dart Sass 3.0.0.
Global built-in functions like mix(), unit(), red(), green(), and blue() are deprecated.
Suggestions include using @use/@forward, color.mix, math.unit, and color.channel.
These warnings originate from Bootstrap’s own SCSS files (e.g., _functions.scss, _variables.scss, bootstrap.scss).
Please update Bootstrap’s Sass source to use the new module system and built-in functions to ensure future compatibility.

Motivation and context

As a developer using Bootstrap with modern build tools and the latest Dart Sass, I want to ensure my projects remain compatible with future Sass releases. The current use of deprecated @import rules and global built-in functions in Bootstrap’s Sass source generates many warnings and will eventually break when Dart Sass 3.0.0 is released. Migrating Bootstrap’s Sass to the new module system and updated functions will help the community avoid build issues, reduce warning noise, and ensure long-term compatibility.

[julien-deramond]

Closing as duplicate of #40962 (and other Sass deprecation warnings issues in the repo)