body { 
    background: #e0f2f1; 
    display: flex; 
    flex-direction: column; 
    align-items: center; 
    font-family: 'Zen Maru Gothic', sans-serif; 
    margin: 0;
    padding-top: 20px;
    padding-bottom: 40px; /* 下部に余白を追加 */
}
#quiz-container { 
    background: #fffcf2; 
    padding: 20px; 
    border-radius: 12px; 
    box-shadow: 0 8px 16px rgba(0,0,0,0.1); 
    margin-top: 15px;
    display: flex;
    flex-direction: column;
    align-items: center;
}
canvas {
    background: transparent;
}
#keyboard { 
    display: flex; 
    margin-top: 15px; 
    justify-content: center;
}
.key { 
    width: 45px; 
    height: 140px; 
    border: 1px solid #333; 
    background: white; 
    cursor: pointer; 
    text-align: center; 
    padding-top: 110px; 
    font-weight: bold; 
    border-radius: 0 0 5px 5px;
    box-shadow: 0 3px 5px rgba(0,0,0,0.2);
    box-sizing: border-box;
    user-select: none; 
}
.key:active { 
    background: #eee; 
    box-shadow: 0 1px 2px rgba(0,0,0,0.2);
    transform: translateY(2px);
}
.back-btn { 
    align-self: flex-start;
    margin-left: 20px; 
    text-decoration: none; 
    color: #333; 
    font-weight: bold; 
    background: white;
    padding: 10px 20px;
    border-radius: 20px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.mode-btn {
    background-color: #ff9800;
    color: white;
    border: none;
    padding: 12px 24px;
    border-radius: 30px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    box-shadow: 0 4px 6px rgba(255, 152, 0, 0.3);
    margin-top: 10px;
}
.listen-btn {
    background-color: #4caf50;
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 20px;
    font-size: 1rem;
    font-weight: bold;
    cursor: pointer;
    margin-top: -10px;
    margin-bottom: 15px;
}
#message {
    font-size: 1.2rem;
    font-weight: bold;
    color: #333;
    height: 30px; 
    margin-top: 10px;
}

#stats-container {
    display: flex;
    gap: 15px;
    margin-top: 20px;
    width: 100%;
    max-width: 400px;
    justify-content: center;
}
.stat-box {
    background: white;
    padding: 8px 12px;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: bold;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    color: #444;
}
.reading-stat { border-bottom: 3px solid #e91e63; }
.ear-stat { border-bottom: 3px solid #ff9800; }

/* ★SEOテキストボックスのデザイン */
.seo-text-box {
    width: 90%;
    max-width: 600px;
    margin-top: 40px;
    background-color: rgba(255, 255, 255, 0.8);
    padding: 20px;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.05);
    color: #555;
    line-height: 1.6;
}
.seo-text-box h1 {
    font-size: 1.1rem;
    color: #00796b;
    margin-top: 0;
    margin-bottom: 10px;
    border-bottom: 2px solid #b2dfdb;
    padding-bottom: 5px;
}
.seo-text-box p {
    font-size: 0.9rem;
    margin: 0;
}