* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --text-color: #2c3e50;
    --text-light: #7f8c8d;
    --background-color: #ffffff;
    --border-color: #ecf0f1;
    --hover-color: #f8f9fa;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-size-base: 16px;
    --line-height-base: 1.6;
    
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-xxl: 3rem;
    
    --border-radius: 8px;
    --box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--text-color);
    background-color: var(--background-color);
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* Header Styles */
.header {
    background: var(--background-color);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-md);
    max-width: 1200px;
    margin: 0 auto;
}

.nav-brand {
    display: flex;
    align-items: center;
}

.nav-brand a {
    display: flex;
    align-items: center;
    text-decoration: none;
    color: var(--primary-color);
}

.logo {
    width: 40px;
    height: 40px;
    margin-right: var(--spacing-sm);
}

.brand-text {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-links {
    display: flex;
    gap: var(--spacing-xl);
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

.nav-link:hover,
.nav-link.active {
    color: var(--secondary-color);
}

.nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--secondary-color);
}

.mobile-menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-sm);
}

.mobile-menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--primary-color);
    margin: 2px 0;
    transition: var(--transition);
}

/* Cookie Banner */
.cookie-banner {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--primary-color);
    color: white;
    padding: var(--spacing-md);
    z-index: 1000;
    transform: translateY(100%);
    transition: transform 0.3s ease;
}

.cookie-banner.show {
    transform: translateY(0);
}

.cookie-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    gap: var(--spacing-md);
}

.cookie-content p {
    margin: 0;
    flex: 1;
}

/* Buttons */
.btn-primary,
.btn-secondary {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    border: 2px solid;
    cursor: pointer;
    font-size: var(--font-size-base);
}

.btn-primary {
    background: var(--secondary-color);
    color: white;
    border-color: var(--secondary-color);
}

.btn-primary:hover {
    background: #2980b9;
    border-color: #2980b9;
}

.btn-secondary {
    background: transparent;
    color: var(--secondary-color);
    border-color: var(--secondary-color);
}

.btn-secondary:hover {
    background: var(--secondary-color);
    color: white;
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, #f8f9fa 0%, #e9ecef 100%);
    padding: var(--spacing-xxl) 0;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('/assets/hero-bg.svg') no-repeat center center;
    background-size: cover;
    opacity: 0.05;
    z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 800px;
    margin: 0 auto;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: var(--spacing-md);
    color: var(--primary-color);
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-light);
    margin-bottom: var(--spacing-xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.hero-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

/* Featured Books Section */
.featured-books {
    padding: var(--spacing-xxl) 0;
}

.featured-books h2 {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: var(--spacing-md);
    color: var(--primary-color);
}

.section-intro {
    text-align: center;
    font-size: 1.125rem;
    color: var(--text-light);
    margin-bottom: var(--spacing-xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-xl);
    margin-top: var(--spacing-xl);
}

.book-card {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
    transition: var(--transition);
}

.book-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
}

.book-image {
    width: 100%;
    height: 200px;
    object-fit: cover;
    background: var(--hover-color);
}

.book-content {
    padding: var(--spacing-lg);
}

.book-category {
    color: var(--secondary-color);
    font-size: 0.875rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: var(--spacing-sm);
}

.book-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    color: var(--primary-color);
}

.book-author {
    color: var(--text-light);
    margin-bottom: var(--spacing-md);
    font-style: italic;
}

.book-description {
    color: var(--text-color);
    margin-bottom: var(--spacing-lg);
    line-height: 1.6;
}

.book-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.book-link {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

.book-link:hover {
    color: #2980b9;
}

/* Categories Preview */
.categories-preview {
    background: var(--hover-color);
    padding: var(--spacing-xxl) 0;
}

.categories-preview h2 {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: var(--spacing-xl);
    color: var(--primary-color);
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.category-card {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--border-radius);
    text-align: center;
    box-shadow: var(--box-shadow);
    transition: var(--transition);
}

.category-card:hover {
    transform: translateY(-3px);
}

.category-card h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
    font-size: 1.5rem;
}

.category-card p {
    color: var(--text-light);
    margin-bottom: var(--spacing-lg);
}

.category-link {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

.category-link:hover {
    color: #2980b9;
}

/* Search and Filter */
.search-filter {
    background: var(--hover-color);
    padding: var(--spacing-xl) 0;
    margin-bottom: var(--spacing-xl);
}

.search-controls {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
}

.search-input,
.filter-select {
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: var(--font-size-base);
    transition: var(--transition);
}

.search-input:focus,
.filter-select:focus {
    outline: none;
    border-color: var(--secondary-color);
}

.search-input {
    min-width: 300px;
}

/* Book Detail Page */
.book-detail {
    padding: var(--spacing-xl) 0;
}

.book-detail-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-xxl);
    align-items: start;
}

.book-detail-image {
    width: 100%;
    max-width: 400px;
    height: auto;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.book-detail-info h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
}

.book-detail-meta {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
}

.meta-item {
    background: var(--hover-color);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius);
    font-size: 0.875rem;
    color: var(--text-light);
}

.book-description-long {
    margin-bottom: var(--spacing-xl);
    font-size: 1.125rem;
    line-height: 1.7;
}

.key-takeaways {
    margin-bottom: var(--spacing-xl);
}

.key-takeaways h3 {
    margin-bottom: var(--spacing-md);
    color: var(--primary-color);
}

.key-takeaways ul {
    list-style: none;
    padding: 0;
}

.key-takeaways li {
    padding: var(--spacing-sm) 0;
    padding-left: var(--spacing-lg);
    position: relative;
}

.key-takeaways li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: bold;
}

.external-links {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.disclaimer-note {
    background: var(--hover-color);
    padding: var(--spacing-md);
    border-radius: var(--border-radius);
    margin: var(--spacing-xl) 0;
    border-left: 4px solid var(--warning-color);
}

/* Footer */
.footer {
    background: var(--primary-color);
    color: white;
    padding: var(--spacing-xxl) 0 var(--spacing-lg);
    margin-top: var(--spacing-xxl);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: var(--spacing-md);
    color: white;
}

.footer-section ul {
    list-style: none;
}

.footer-section li {
    margin-bottom: var(--spacing-sm);
}

.footer-section a {
    color: #bdc3c7;
    text-decoration: none;
    transition: var(--transition);
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    border-top: 1px solid #34495e;
    padding-top: var(--spacing-md);
    text-align: center;
    color: #bdc3c7;
}

/* Form Styles */
.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    color: var(--primary-color);
}

.form-input,
.form-textarea {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: var(--font-size-base);
    font-family: var(--font-family);
    transition: var(--transition);
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--secondary-color);
}

.form-textarea {
    resize: vertical;
    min-height: 120px;
}

.contact-info {
    background: var(--hover-color);
    padding: var(--spacing-xl);
    border-radius: var(--border-radius);
    margin-top: var(--spacing-xl);
}

.contact-item {
    margin-bottom: var(--spacing-md);
}

.contact-item:last-child {
    margin-bottom: 0;
}

.contact-item strong {
    color: var(--primary-color);
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: white;
        flex-direction: column;
        padding: var(--spacing-md);
        border-top: 1px solid var(--border-color);
        gap: var(--spacing-md);
    }
    
    .nav-links.active {
        display: flex;
    }
    
    .mobile-menu-toggle {
        display: flex;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .books-grid {
        grid-template-columns: 1fr;
    }
    
    .book-detail-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .search-controls {
        flex-direction: column;
        align-items: stretch;
    }
    
    .search-input {
        min-width: auto;
    }
    
    .cookie-content {
        flex-direction: column;
        text-align: center;
    }
    
    .external-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .hero {
        padding: var(--spacing-xl) 0;
    }
    
    .featured-books,
    .categories-preview {
        padding: var(--spacing-xl) 0;
    }
    
    .brand-text {
        font-size: 1.25rem;
    }
    
    .categories-grid {
        grid-template-columns: 1fr;
    }
    
    .book-detail-info h1 {
        font-size: 2rem;
    }
}

/* Print Styles */
@media print {
    .header,
    .footer,
    .hero-actions,
    .external-links,
    .cookie-banner {
        display: none;
    }
    
    body {
        font-size: 12pt;
        line-height: 1.4;
    }
    
    .book-detail-content {
        grid-template-columns: 1fr;
    }
}