Fix the Sass Breaking Change: Color Functions

[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!)
  Direction are on the Sass page!

• Anything else?
  You can see the deprecation warnings in the test runs, either locally or in the CI! We are using lighten() and darken()

[lomky]

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