Refactors CSS in `static/css/styles.css` to update the visual appearance of `.stats-card` elements and various buttons, aligning them with a card-like design and modifying hover states for buttons to have a blue outline without fill.
Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 5e584ab0-c340-4432-97ef-1972582b60e9
Replit-Commit-Checkpoint-Type: full_checkpoint
Replit-Commit-Event-Id: 0f7ec833-2506-47a7-a9c1-3258833d5cd0
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/d0a1d46d-d203-4308-bc6a-312ac7c0243b/5e584ab0-c340-4432-97ef-1972582b60e9/X0ztToo
