:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --success-color: #27ae60;
    --warning-color: #f39c12;
    --text-color: #333;
    --text-light: #666;
    --bg-light: #f8f9fa;
    --bg-white: #ffffff;
    --border-color: #ddd;
    --shadow: 0 2px 10px rgba(0,0,0,0.1);
    --shadow-hover: 0 5px 20px rgba(0,0,0,0.15);
    --transition: all 0.3s ease;
    --font-primary: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --font-heading: 'Georgia', serif;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    color: var(--text-color);
    line-height: 1.6;
    background-color: var(--bg-white);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.btn {
    display: inline-block;
    padding: 12px 30px;
    background-color: var(--secondary-color);
    color: white;
    text-decoration: none;
    border-radius: 5px;
    border: none;
    cursor: pointer;
    font-size: 16px;
    transition: var(--transition);
    font-weight: 500;
}

.btn:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

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

.btn-primary:hover {
    background-color: #1a252f;
}

.btn-success {
    background-color: var(--success-color);
}

.btn-success:hover {
    background-color: #229954;
}

.btn-danger {
    background-color: var(--accent-color);
}

.btn-danger:hover {
    background-color: #c0392b;
}

header {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem 0;
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.logo h1 {
    font-family: var(--font-heading);
    font-size: 1.8rem;
    font-weight: 600;
}

.logo a {
    color: white;
    text-decoration: none;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 2rem;
}

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

nav a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--secondary-color);
    transition: var(--transition);
}

nav a:hover::after {
    width: 100%;
}

.hero {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 100px 0;
    text-align: center;
}

.hero h1 {
    font-family: var(--font-heading);
    font-size: 3rem;
    margin-bottom: 1rem;
    animation: fadeInUp 1s ease;
}

.hero p {
    font-size: 1.3rem;
    margin-bottom: 2rem;
    animation: fadeInUp 1s ease 0.2s;
    animation-fill-mode: both;
}

.hero .btn {
    animation: fadeInUp 1s ease 0.4s;
    animation-fill-mode: both;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.section {
    padding: 80px 0;
}

.section-title {
    font-family: var(--font-heading);
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--primary-color);
}

.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 2rem;
}

.book-card {
    background: white;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.book-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-hover);
}

.book-image {
    width: 100%;
    height: 400px;
    object-fit: cover;
}

.book-info {
    padding: 1.5rem;
}

.book-title {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.book-description {
    color: var(--text-light);
    margin-bottom: 1rem;
    line-height: 1.6;
}

.book-price {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.book-formats {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

.format-badge {
    padding: 5px 10px;
    background-color: var(--bg-light);
    border-radius: 5px;
    font-size: 0.9rem;
}

.news-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
}

.news-card {
    background: white;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.news-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

.news-image {
    width: 100%;
    height: 250px;
    object-fit: cover;
}

.news-content {
    padding: 1.5rem;
}

.news-date {
    color: var(--text-light);
    font-size: 0.9rem;
    margin-bottom: 0.5rem;
}

.news-title {
    font-family: var(--font-heading);
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.news-excerpt {
    color: var(--text-light);
    line-height: 1.6;
}

.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 1.5rem;
}

.gallery-item {
    position: relative;
    overflow: hidden;
    border-radius: 10px;
    box-shadow: var(--shadow);
    cursor: pointer;
}

.gallery-item img {
    width: 100%;
    height: 300px;
    object-fit: cover;
    transition: var(--transition);
}

.gallery-item:hover img {
    transform: scale(1.1);
}

.gallery-overlay {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(to top, rgba(0,0,0,0.8), transparent);
    color: white;
    padding: 1.5rem;
    transform: translateY(100%);
    transition: var(--transition);
}

.gallery-item:hover .gallery-overlay {
    transform: translateY(0);
}

.contact-form {
    max-width: 600px;
    margin: 0 auto;
    background: white;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: var(--shadow);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: var(--primary-color);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-size: 16px;
    transition: var(--transition);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--secondary-color);
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.1);
}

.alert {
    padding: 1rem 1.5rem;
    border-radius: 5px;
    margin-bottom: 1rem;
}

.alert-success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.alert-error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.alert-warning {
    background-color: #fff3cd;
    color: #856404;
    border: 1px solid #ffeaa7;
}

footer {
    background-color: var(--primary-color);
    color: white;
    padding: 3rem 0 1rem;
    margin-top: 4rem;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3 {
    margin-bottom: 1rem;
    font-family: var(--font-heading);
}

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

.footer-section ul li {
    margin-bottom: 0.5rem;
}

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

.footer-section a:hover {
    color: var(--secondary-color);
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    display: inline-block;
    width: 40px;
    height: 40px;
    background-color: var(--secondary-color);
    border-radius: 50%;
    text-align: center;
    line-height: 40px;
    transition: var(--transition);
}

.social-links a:hover {
    background-color: white;
    color: var(--secondary-color);
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255,255,255,0.1);
}

.checkout-container {
    max-width: 800px;
    margin: 0 auto;
}

.payment-methods {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.payment-method {
    padding: 1.5rem;
    border: 2px solid var(--border-color);
    border-radius: 10px;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
}

.payment-method:hover {
    border-color: var(--secondary-color);
    box-shadow: var(--shadow);
}

.payment-method.active {
    border-color: var(--secondary-color);
    background-color: rgba(52, 152, 219, 0.1);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    color: white;
    font-size: 1.5rem;
    cursor: pointer;
}

@media (max-width: 768px) {
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1.1rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    nav ul {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: var(--primary-color);
        padding: 1rem;
    }
    
    nav ul.active {
        display: flex;
    }
    
    .mobile-menu-toggle {
        display: block;
    }
    
    .books-grid,
    .news-grid,
    .gallery-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
}

.loader {
    border: 4px solid var(--bg-light);
    border-top: 4px solid var(--secondary-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 2rem auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}