Connects to #244. Connects to #245. GA4 migration and office hour banner.

[jimmyzhen]

Key Changes:

• The Office Hour banner has been moved towards the bottom of the homepage
• The primary announcement banner at top has been made a bit more prominent
• Google Universal Analytics to Google Analytics 4 migration

[jimmyzhen]

Thanks, @cteng585! It's indeed a good idea to add the field you suggested.

Regarding your second suggestion, I will need to think about the implementation for a future update.