NEON ARENA ATTACHED UI WRAPPER

1. Put index.html and style.css beside your existing game.js.
2. Keep the filenames unchanged, or update the link/script paths in index.html.
3. The original IDs remain intact: game, join, name, play, error, hud, status, scores.
4. Decorative UI is pointer-events:none, so it will not block canvas controls.
5. Add the class "hidden" to #join after connecting and remove it from #hud when gameplay begins.

The wrapper is responsive: side inventory rails disappear on narrow mobile screens while the join panel and compact hotbar remain visible.