U4 Issue 5: UI/UX(Indicator of pinned)

### Description

Effort: We estimate that this will take 2-3 hours.
	Size: Small
	Dependencies: Issues 3 + 4
	Assignments: Partner 1
	Milestone: Sprint 2
	Acceptance Criteria:
		Pinned Posts stand out(visible indicator)
		No impact on accessibility or layout


### Community forum reference

_No response_