refactor: perform saas slash-div migration

[setchy]

Description

Address build warnings by running https://sass-lang.com/documentation/breaking-changes/slash-div/#automatic-migration

Addressed Issue

Address a number of warnings such as the example below

Deprecation Warning: Using / for division outside of calc() is deprecated and will be removed in Dart Sass 2.0.0.

Recommendation: math.div(4em, 14) or calc(4em / 14)

More info and automated migrator: https://sass-lang.com/d/slash-div

Additional Details

Checklist

• I have read and understand the contributing guidelines
• This PR introduces new or alters existing behavior, and I have updated the documentation accordingly