:root{
  --bg:#08131b;--bg2:#0d1f2a;--panel:#122b38;--panel2:#173847;--border:#28566c;
  --text:#f4fbff;--muted:#95b8c8;--accent:#22c55e;--accent2:#16a34a;--danger:#ef4444;
}
*{box-sizing:border-box}
body{margin:0;font-family:Inter,Segoe UI,Arial,sans-serif;background:linear-gradient(180deg,var(--bg),var(--bg2));color:var(--text)}
button,a{font:inherit}button{cursor:pointer}
.topbar{display:flex;justify-content:space-between;align-items:center;gap:18px;padding:24px max(18px,calc((100% - 1280px)/2));border-bottom:1px solid var(--border);background:#0a1822}
.topbar h1{margin:4px 0 6px;font-size:clamp(26px,4vw,40px)}
.topbar p{margin:0;color:var(--muted)}
.eyebrow{font-size:12px;letter-spacing:.16em;color:#86efac;font-weight:800}
.levels{display:flex;gap:8px;flex-wrap:wrap}
.levels a{text-decoration:none;color:var(--text);padding:9px 12px;border:1px solid var(--border);border-radius:9px;background:var(--panel)}
.levels a.active{border-color:var(--accent);color:#86efac}
.game-shell{max-width:1280px;margin:auto;display:grid;grid-template-columns:280px minmax(0,1fr);gap:20px;padding:22px}
.panel{background:rgba(18,43,56,.96);border:1px solid var(--border);border-radius:18px;padding:18px}
.sidebar{align-self:start}.stats{display:grid;gap:9px}
.stats div{display:flex;justify-content:space-between;gap:10px;padding:11px 12px;background:var(--panel2);border:1px solid var(--border);border-radius:10px}
.stats span{color:var(--muted);font-size:13px}.stats strong{font-size:18px}
.actions{display:grid;gap:9px;margin-top:16px}
.actions button{border:1px solid var(--border);background:var(--panel2);color:var(--text);padding:11px;border-radius:10px}
.primary{background:var(--accent)!important;color:#052e16!important;border-color:transparent!important;font-weight:800}
.rules{margin-top:18px;padding-top:16px;border-top:1px solid var(--border)}
.rules p{color:var(--muted);font-size:13px;line-height:1.5}
.play-area{display:grid;gap:16px;min-width:0}
.game-head{display:flex;justify-content:space-between;gap:14px;align-items:flex-start;flex-wrap:wrap}
.mode-label{font-size:11px;letter-spacing:.12em;color:var(--muted)}
.game-head h2{margin:3px 0 12px}
.legend{display:flex;gap:12px;flex-wrap:wrap;font-size:12px;color:var(--muted)}
.box{display:inline-block;width:14px;height:14px;border-radius:3px;margin-right:5px;vertical-align:-2px}
.box.snake{background:#22c55e}.box.food{background:#ef4444}.box.obstacle{background:#94a3b8}
.canvas-wrap{display:flex;justify-content:center;overflow:auto;background:#071018;border:1px solid var(--border);border-radius:14px;padding:12px}
canvas{display:block;width:min(100%,600px);height:auto;background:#061017;border-radius:10px}
.mobile-controls{display:grid;justify-content:center;gap:6px;margin-top:16px}
.mobile-controls>button{justify-self:center}
.mobile-controls div{display:flex;gap:6px}
.mobile-controls button{width:54px;height:54px;border-radius:12px;border:1px solid var(--border);background:var(--panel2);color:var(--text);font-weight:900}
.message{color:var(--muted)}
.message.good{border-color:var(--accent);color:#bbf7d0}.message.bad{border-color:var(--danger);color:#fecaca}
footer{text-align:center;padding:20px;color:var(--muted);font-size:12px}
@media(max-width:900px){.game-shell{grid-template-columns:1fr}}
@media(max-width:520px){.game-shell{padding:10px}.panel{padding:13px}.levels{width:100%}.levels a{flex:1;text-align:center}}

canvas:focus{
  outline:3px solid rgba(134,239,172,.45);
  outline-offset:4px;
}
.mobile-controls button:active{
  transform:scale(.94);
  background:#22c55e;
  color:#052e16;
}