/* Card Container */
    .product-card-wrap {
        max-width: 100%;
        margin: 20px auto;
        padding: 25px;
        background: #fff;
        border: 1px solid #e1e1e1;
        border-radius: 12px;
        box-shadow: 0 4px 15px rgba(0,0,0,0.05);
    }

    /* Main Section Layout */
    .main-section { display: flex; gap: 25px; flex-wrap: wrap; }
    
    .book-thumb { 
        width: 200px; 
        height: auto; 
        object-fit: contain; 
        border-radius: 6px; 
    }

    .content-box { flex: 1; min-width: 250px; }
    .content-box h2 { font-size: 24px; margin-bottom: 10px; color: #000; }
    
    .lang-badge { 
        display: inline-block; padding: 4px 10px; background: #f4f4f4; 
        font-size: 12px; font-weight: 600; border-radius: 4px; margin-bottom: 15px; 
    }
    
    .description { font-size: 14px; color: #555; line-height: 1.6; margin-bottom: 20px; }
    
    .btn-buy { 
        background: #000; color: #fff; padding: 10px 20px; 
        text-decoration: none; font-weight: bold; font-size: 14px;
        border-radius: 5px; display: inline-block;
    }

    /* PDF Preview Section */
    .preview-section { margin-top: 30px; border-top: 1px solid #eee; padding-top: 20px; }
    .toggle-btn { 
        cursor: pointer; color: #000; font-size: 14px; 
        text-decoration: underline; font-weight: 600; margin-bottom: 10px;
    }
    .pdf-embed { 
        width: 100%; height: 500px; /* Fixed height for better visibility */
        display: none; /* Initially hidden */
        border: 1px solid #ddd; border-radius: 4px;
    }