.book-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 20px;
}
.book-card {
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 15px;
    background-color: #f9f9f9;
    transition: transform 0.3s ease;
    position: relative;
}
.book-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}
.book-title {
    font-size: 18px;
    font-weight: bold;
    margin-bottom: 8px;
    color: #333;
}
.book-english-title {
    font-size: 14px;
    color: #666;
    margin-bottom: 10px;
    font-style: italic;
}
.book-description {
    font-size: 14px;
    margin-bottom: 15px;
    color: #444;
}
.book-link {
    display: inline-block;
    padding: 8px 12px;
    background-color: #4285f4;
    color: white;
    text-decoration: none;
    border-radius: 4px;
    font-size: 14px;
    transition: background-color 0.3s ease;
}
.book-link:hover {
    background-color: #3367d6;
}
.category-filter {
    margin-bottom: 20px;
}
.search-bar {
    margin-bottom: 20px;
}
.search-bar input {
    padding: 8px;
    border-radius: 4px;
    border: 1px solid #ddd;
    width: 300px;
}

/* 書籍カテゴリタブのスタイル */
.book-categories {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 25px;
    justify-content: center;
}

.category-tab {
    padding: 8px 15px;
    background-color: #f5f5f5;
    border: 1px solid #e0e0e0;
    border-radius: 5px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: all 0.3s ease;
    text-decoration: none;
    color: #333;
}

.category-tab:hover {
    background-color: #e8e8e8;
}

.category-tab.active {
    background-color: #4a86e8;
    color: white;
    border-color: #4a86e8;
}

/* カテゴリバッジのスタイル */
.book-category-badge {
    position: absolute;
    top: 0;
    left: 0;
    background-color: rgba(0,0,0,0.6);
    color: white;
    padding: 3px 8px;
    font-size: 0.7rem;
    border-radius: 0 0 5px 0;
}

/* スマホ向け調整 */
@media (max-width: 767px) {
    .book-categories {
        overflow-x: auto;
        padding-bottom: 5px;
    }
    
    .category-tab {
        white-space: nowrap;
    }
}

/* 非表示項目 - デフォルトでは全て表示 */
.book-item.hidden {
    display: none;
}

.amazon-disclaimer {
    font-size: 12px;
    color: #666;
    margin-top: 30px;
    text-align: center;
}