Description:
The post-avatar component is missing proper hover and focus color behaviors in specific contexts:

1. When nested inside an anchor tag:
   The hover color is not applied.
2. When inside a button:
   The hover effect is missing.
   The focus color is applied incorrectly, appearing on top of the avatar border.
   

Steps to Reproduce:

1. Enable high contrast mode in the browser or system settings.
2. Navigate to a page for post-avatar component.
3. Hover over or focus on the component nested inside the anchor tag and a button.
4. Observe the missing or inconsistent hover and focus styles.