Refactor all outdated Tailwind CSS utility classes to Tailwind v4

[QwertyNora]

Refactor all outdated Tailwind utility classes in the codebase to use Tailwind v4 utility classes.

Refer to the provided screenshot for an example of what needs to be updated:

Task details:

• Identify and replace all utility classes from previous Tailwind versions with their v4 equivalents (e.g., replace rounded-[6px] with the new canonical classes like rounded-md).
• Ensure consistent use of updated utility class conventions.
• Test for visual and functional regressions after refactoring.
• Reference Tailwind v4 upgrade guide as needed.

Acceptance Criteria:

1. All non-v4 utility class usages are updated to v4 syntax and best practices across the project.
2. No visual regressions are present in the UI after the update.
3. Code passes all linting and tests.