body { margin:0; background:#000; color:white; font-family:sans-serif; overflow:hidden; }
video { position:fixed; inset:0; width:100%; height:100%; object-fit:cover; }
.center { position:absolute; inset:0; display:flex; flex-direction:column; align-items:center; justify-content:center; text-align:center; }
.arenas button, #begin { margin:6px; padding:10px 16px; border-radius:20px; border:none; }
canvas { position:fixed; inset:0; }
.hidden { display:none; }
.card { background:rgba(0,0,0,.7); padding:20px; border-radius:20px; }
.orb { width:200px; height:200px; border-radius:50%; background:radial-gradient(circle, gold, rgba(255,215,0,.2)); margin:auto; margin-top:30vh; animation: breathe 8s infinite ease-in-out; }
@keyframes breathe { 0% { transform:scale(.9);} 50%{transform:scale(1.1);} 100%{transform:scale(.9);} }