The appointment styling was updated to use the newer Bootstrap color contrast method. This helps keep text readable after the Bootstrap 5 migration and prevents visual inconsistencies in appointment pages.

This commit properly convert `color-yiq` SCSS function calls by
replacing them with `color-contrast`.

Reference:
https://getbootstrap.com/docs/5.1/migration/#sass

This update fixes a visual flicker when viewing or editing approval types. It makes the approvals interface feel smoother and reduces distraction for users managing approval workflows.

taskID 2880859