:root{--bg: #1a1714;--panel: #2a2620;--grid: #3a342c;--cell: #4a443a;--ink: #f6efe2;--dim: #b8ab94;--accent: #edc22e}*{box-sizing:border-box}html,body{margin:0;height:100%}body{background:radial-gradient(900px 560px at 50% -8%,#241f18,var(--bg));color:var(--ink);font-family:system-ui,-apple-system,Segoe UI,sans-serif;display:flex;justify-content:center;-webkit-user-select:none;user-select:none}#app{width:100%;max-width:460px;padding:12px 12px 26px}header{text-align:center;margin-bottom:6px}h1{margin:0;font-size:34px;letter-spacing:1px;font-weight:800;color:var(--accent)}.sub{margin:2px 0 0;color:var(--dim);font-size:13px}.bar{display:flex;gap:8px;justify-content:center;flex-wrap:wrap;align-items:center;margin:9px 0}.seg{display:inline-flex;background:var(--panel);border:1px solid var(--grid);border-radius:999px;overflow:hidden}.seg button{background:none;border:none;color:var(--dim);padding:6px 13px;font:600 13px system-ui;cursor:pointer}.seg button.active{background:var(--accent);color:#3a2c06}.btn{background:var(--panel);border:1px solid var(--grid);color:var(--ink);padding:7px 14px;border-radius:999px;font:700 13px system-ui;cursor:pointer}.btn:hover{border-color:var(--accent)}.scoreboard{display:flex;gap:10px;justify-content:center;margin:8px 0}.readout{background:var(--panel);border:1px solid var(--grid);border-radius:8px;padding:5px 16px;font:800 20px ui-monospace,monospace;color:var(--accent);min-width:90px;text-align:center}.readout span{color:var(--dim);font-size:11px;display:block;font-weight:600;letter-spacing:.5px}.stage{position:relative;display:flex;justify-content:center}.grid{background:var(--grid);border-radius:12px;padding:8px;display:grid;grid-template-columns:repeat(4,1fr);grid-template-rows:repeat(4,1fr);gap:8px;width:min(94vw,420px);aspect-ratio:1;box-sizing:border-box}.cell{background:var(--cell);border-radius:7px;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:clamp(18px,7vw,34px);color:#2a2620;min-width:0;min-height:0}.cell.e{background:#ffffff0a}.cell.t2{background:#eee4da}.cell.t4{background:#ede0c8}.cell.t8{background:#f2b179;color:#fff}.cell.t16{background:#f59563;color:#fff}.cell.t32{background:#f67c5f;color:#fff}.cell.t64{background:#f65e3b;color:#fff}.cell.t128{background:#edcf72;color:#fff;font-size:clamp(15px,6vw,28px)}.cell.t256{background:#edcc61;color:#fff;font-size:clamp(15px,6vw,28px)}.cell.t512{background:#edc850;color:#fff;font-size:clamp(15px,6vw,28px)}.cell.t1024{background:#edc53f;color:#fff;font-size:clamp(12px,5vw,22px)}.cell.t2048{background:#edc22e;color:#fff;font-size:clamp(12px,5vw,22px);box-shadow:0 0 18px #edc22e99}.cell.big{background:#3c3a32;color:#f6efe2;font-size:clamp(12px,5vw,22px)}.overlay{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;background:#14110cc7;border-radius:12px;backdrop-filter:blur(3px)}.overlay.hidden{display:none}.card{background:var(--panel);border:1px solid var(--grid);border-radius:16px;padding:22px 26px;text-align:center;max-width:320px}.card h2{margin:0 0 6px;font-size:26px;color:var(--accent)}.card p{margin:6px 0;color:var(--dim);font-size:14px}.card .row{display:flex;gap:8px;justify-content:center;margin-top:14px}.hint{text-align:center;color:var(--dim);font-size:12px;margin-top:10px}