:root{--bg: #0b0f1a;--panel: #161d2e;--line: #28324a;--ink: #e9eefb;--dim: #94a3c4;--accent: #6ea8fe;--x: #6ea8fe;--o: #ffb454}*{box-sizing:border-box}html,body{margin:0;height:100%}body{background:radial-gradient(900px 560px at 50% -8%,#16203a,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:720px;padding:12px 12px 26px}header{text-align:center;margin-bottom:6px}h1{margin:0;font-size:27px;letter-spacing:6px;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:10px 0}.seg{display:inline-flex;background:var(--panel);border:1px solid var(--line);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:#06122b}.btn{background:var(--panel);border:1px solid var(--line);color:var(--ink);padding:7px 14px;border-radius:999px;font:700 13px system-ui;cursor:pointer}.btn:hover{border-color:var(--accent)}.btn.primary{background:var(--accent);color:#06122b;border-color:var(--accent)}.status{text-align:center;min-height:20px;color:var(--dim);font-size:14px;font-weight:600;margin:4px 0 12px}.rotbar{display:flex;gap:10px;justify-content:center;align-items:center;flex-wrap:wrap;margin:0 0 12px;min-height:30px}.rotbar .btn:disabled{opacity:.45;cursor:default}.rothint{color:var(--dim);font-size:12px}.rots{display:flex;gap:4px}.rotsq{width:24px;height:22px;border-radius:6px;border:1px solid var(--line);background:#0e1424;color:var(--dim);font-size:14px;line-height:1;cursor:pointer;padding:0;display:flex;align-items:center;justify-content:center}.rotsq:disabled{opacity:.35;cursor:default}.rotsq.armed{color:var(--accent);border-color:var(--accent);background:#16233f}.rotsq.armed:hover{background:var(--accent);color:#06122b}.cube{display:flex;gap:14px;justify-content:center;flex-wrap:wrap}.layer{display:flex;flex-direction:column;align-items:center;gap:6px}.lbl{color:var(--dim);font-size:12px;font-weight:700;letter-spacing:1px}.grid{display:grid;grid-template-columns:repeat(4,1fr);gap:4px;background:var(--panel);padding:6px;border-radius:10px;border:1px solid var(--line);box-shadow:0 10px 28px #00000073}.sq{width:34px;height:34px;border-radius:7px;border:1px solid var(--line);background:#0e1424;color:var(--ink);font-size:18px;line-height:1;font-weight:700;display:flex;align-items:center;justify-content:center;cursor:pointer;padding:0;transition:background .12s,transform .05s}.sq:disabled{cursor:default}.sq.playable:hover{background:#1b2742;border-color:var(--accent)}.sq.x{color:var(--x);background:#122036}.sq.o{color:var(--o);background:#2a2113}.sq.last{box-shadow:0 0 0 2px var(--accent) inset}.sq.win{background:#1f5134;color:#c9ffd9;box-shadow:0 0 0 2px #4ade80 inset}.sq.hintcell{box-shadow:0 0 0 2px var(--accent) inset,0 0 12px var(--accent)}.stage{position:relative}.overlay{position:fixed;inset:0;display:flex;align-items:center;justify-content:center;background:#060a14bd;backdrop-filter:blur(3px);z-index:10}.overlay.hidden{display:none}.card{background:var(--panel);border:1px solid var(--line);border-radius:16px;padding:22px 26px;text-align:center;max-width:340px}.card h2{margin:0 0 6px;font-size:24px;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:16px}@media(max-width:520px){.sq{width:30px;height:30px;font-size:16px}.cube{gap:8px}}