.game-container{max-width:980px;margin:0 auto;padding:2rem 1rem}.game-header h1{margin:0 0 1.5rem;font-size:2rem;color:var(--text)}.operations-selection{background:var(--card);border:1px solid var(--border);border-radius:1rem;padding:1rem 1.2rem;margin-bottom:1.5rem}.operations-selection h3{margin:0 0 .75rem;font-size:1rem;color:var(--muted)}.operation-checkboxes{display:flex;flex-wrap:wrap;gap:1rem}.operation-checkboxes label{display:flex;align-items:center;gap:.5rem;cursor:pointer;padding:.5rem .75rem;border-radius:.5rem;transition:background .2s ease}.operation-checkboxes label:hover{background:#ffffff0d}.operation-checkboxes input[type=checkbox]{width:1.2rem;height:1.2rem;accent-color:var(--brand)}.problem-container{background:var(--card);border:2px solid var(--border);border-radius:1rem;padding:2rem;text-align:center;margin-bottom:1.5rem}.working-timer{font-size:.9rem;color:var(--muted);margin-bottom:.75rem}.problem{font-size:2.5rem;font-weight:700;color:var(--text)}.controls{display:flex;gap:1rem;margin-bottom:1.5rem;flex-wrap:wrap}.controls input[type=number]{flex:1;min-width:200px;padding:1rem 1.1rem;border-radius:.8rem;border:1px solid var(--border);background:#0b0d11;color:var(--text);font-size:1.1rem}.controls input[type=number]:focus{outline:3px solid var(--focus);outline-offset:3px}.controls button{padding:1rem 1.5rem;border-radius:.8rem;font-weight:800;cursor:pointer;transition:all .2s ease}.controls #startBtn{background:linear-gradient(90deg,var(--brand),var(--brand-2));color:var(--bg);border:none}.controls #startBtn:hover{opacity:.9}.controls #restartBtn{background:transparent;border:1px solid var(--border);color:var(--text)}.controls #restartBtn:hover{background:#ffffff0d}.stats{display:flex;gap:2rem;justify-content:center;margin-bottom:1.5rem}.stat{background:var(--card);border:1px solid var(--border);border-radius:.8rem;padding:.75rem 1.5rem;font-weight:600}.stat span{color:var(--brand);font-weight:900}.message{text-align:center;padding:1rem;border-radius:.8rem;margin-bottom:1rem}.message.success{background:#22c55e1a;border:1px solid var(--brand);color:var(--brand)}.message.error{background:#ef44441a;border:1px solid #ef4444;color:#ef4444}.message.info{background:#60a5fa1a;border:1px solid var(--focus);color:var(--focus)}