fix: sass calculations

[amagana8]

Description

Put sass value calculations inside a calc() as using / for division is deprecated and will be removed in dart Sass 2.0.0. Moving forward it is recommended to use calc() for such operations.

Related Issue

Motivation and Context

How Has This Been Tested?

Screenshots:

Before (If applicable):

After:

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.