.qm-board {
    padding: 32px 16px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    text-align: center;
}

.qm-problem {
    margin: 0 0 20px;
    font-size: clamp(2rem, 9vw, 3.25rem);
    font-weight: 700;
    font-variant-numeric: tabular-nums;
}

.qm-problem strong { color: var(--accent); }

.qm-form { display: flex; gap: 8px; justify-content: center; }

.qm-input {
    width: 8ch;
    padding: 8px 12px;
    border: 2px solid var(--border);
    border-radius: 8px;
    background: var(--bg);
    color: var(--text);
    font: inherit;
    font-size: 1.5rem;
    text-align: center;
}

.qm-input:focus { outline: none; border-color: var(--accent); }

.qm-form .game-button { margin-left: 0; }

.qm-form .game-button:disabled { opacity: 0.5; cursor: default; }

.qm-board.is-correct { animation: qm-flash-correct 0.4s; }
.qm-board.is-wrong { animation: qm-flash-wrong 0.4s; }

@keyframes qm-flash-correct { from { box-shadow: 0 0 0 4px #2e9d5b; } }
@keyframes qm-flash-wrong { from { box-shadow: 0 0 0 4px #d93025; } }

@media (prefers-reduced-motion: reduce) {
    .qm-board.is-correct, .qm-board.is-wrong { animation: none; }
}