Fix the Sass Breaking Change: abs() Percentage

[lomky]

Thanks for creating an issue! Please fill out this form so we can be sure to have all the information we need, and to minimize back and forth.

• What are we trying to do? Keep our frontend code up to date

• What feature or behavior is this required for? Continued frontend functioning!

• How could we solve this issue? (Not knowing is okay!) Documented fix here - tldr use math.abs() instead of abs()

• Anything else? You can see the deprecation warnings in the test runs, either locally or in the CI!

[lomky]

(I think this might just be we need to upgrade bootstrap)