* {
    box-sizing: border-box;
    font-family: Arial, sans-serif;
}

body {
    display: flex;
    justify-content: center;
    align-items: flex-start;
    background-color: #f0f8ff;
    min-height: 100vh;
    margin: 0;
    padding: 20px;
    position: relative;
}

.container {
    width: 100%;
    max-width: 400px;
    background-color: #ffffff;
    border-radius: 15px;
    padding: 20px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
    text-align: center;
}

#description {
    font-size: 18px;
    margin-bottom: 10px;
}

#score-container {
    font-size: 20px;
    margin-bottom: 15px;
}

#game-container {
    background-color: #e0f7fa;
    border-radius: 15px;
    padding: 15px;
    margin-bottom: 15px;
    position: relative;
}

#problem {
    font-size: 32px;
    margin-bottom: 15px;
}

#choices {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

.choice-btn {
    font-size: 20px;
    padding: 15px;
    border-radius: 10px;
    border: none;
    background-color: #ffd54f;
    cursor: pointer;
    transition: transform 0.2s, background-color 0.2s;
}

.choice-btn:hover {
    transform: scale(1.1);
    background-color: #ffca28;
}

#button-container {
    margin-top: 10px;
}

#start-btn {
    font-size: 22px;
    padding: 10px 20px;
    border-radius: 12px;
    border: none;
    background-color: #4caf50;
    color: white;
    cursor: pointer;
}

#start-btn:hover {
    background-color: #45a049;
}

canvas {
    position: absolute;
    top: 0;
    left: 0;
    pointer-events: none;
}

/* 間違い時の揺れアニメーション */
@keyframes shakeAnim {
    0% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    50% { transform: translateX(5px); }
    75% { transform: translateX(-5px); }
    100% { transform: translateX(0); }
}

.shake {
    animation: shakeAnim 0.3s;
}