This pass fixes the two screenshot issues from the PROFESSIONAL_ADMIN_PUBLIC_REPAIR build:

1. Homepage featured cards
- Constrained featured news/event media into a fixed card area
- Forced clean cover sizing so images no longer blow out the layout
- Kept featured content admin-driven

2. Join the Team page
- Rebuilt the form into a centered structured card
- Added proper labels above fields
- Added neon-glow field styling
- Fixed spacing, alignment, and upload/button presentation

Files changed:
- join.php
- css/site.css
