#quiz-panel {
    height: 150px; /* 固定高度，或者让 flex-basis 控制 */
    background: #ecf0f1;
    color: #333;
    display: flex;
    flex-direction: column;
    padding: 10px 20px;
    z-index: 5;
    box-shadow: 0 -4px 8px rgba(0,0,0,0.2);
    position: relative; /* feedback overlay 定位基准 */
}

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

#feedback-overlay {
    position: absolute; top:0; left:0; right:0; bottom:0;
    background: rgba(255,255,255,0.8);
    display: none; justify-content: center; align-items: center;
    z-index: 10;
}
.feedback-mark { font-size: 80px; color: red; }

.quiz-main {
    display: flex;
    flex: 1;
    align-items: center;
}

.question-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin-right: 20px;
    min-width: 80px;
}

#main-display {
    font-size: 48px;
    font-weight: bold;
    color: #d35400;
}

.options-grid {
    flex: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
    height: 100%;
}

.option-btn {
    background: #3498db;
    color: white;
    border: none;
    padding: 5px;
    font-size: 20px;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
}

.speaker-btn {
    font-size: 24px;
    cursor: pointer;
    background: #f1c40f;
    border-radius: 50%;
    padding: 5px;
    margin-top: 5px;
}

/* 移动端喇叭闪烁提示：提醒用户点击发音 */
.speaker-hint {
    animation: speaker-pulse 0.5s ease-in-out 3;
}

@keyframes speaker-pulse {
    0%, 100% { transform: scale(1); background: #f1c40f; }
    50% { transform: scale(1.3); background: #e74c3c; }
}