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

body {
    font-family: 'Segoe UI', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f9f9f9;
}



/* Header */
.header {
    background: white;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
    padding: 0;
}

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

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 20px;
}

.logo {
    font-size: 1.8rem;
    font-weight: bold;
    color: #2c3e50;
}

a {
    text-decoration: none;
}

.nav a {
    margin-left: 2rem;
    text-decoration: none;
    color: #555;
    transition: color 0.3s;
}

.nav a:hover {
    color: #3498db;
}

/* Main sections */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: 4rem 0;
}

.hero h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
}

/* Кнопки */
.btn {
    display: inline-block;
    padding: 12px 24px;
    border: none;
    border-radius: 10px;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    
}

.btn-primary {
    background: #3498db;
    color: white;
}

.btn-primary:hover {
    background: #2980b9;
    transform: translateY(-2px);
}

.btn-secondary {
    background: transparent;
    color: #3498db;
    border: 2px solid #3498db;
    margin-top: 1rem;
}

.btn-secondary:hover {
    background: #3498db;
    color: white;
}

/* Секция с уроками */
.lessons-section {
    padding: 3rem 0;
    background: white;
}

.lessons-section h3 {
    text-align: center;
    margin-bottom: 2rem;
    font-size: 2rem;
    color: #2c3e50;
}

.lessons-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.lesson-card {
    background: #fff;
    border-radius: 8px;
    padding: 2rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s, box-shadow 0.3s;
    text-align: center;
}

.unactive {
    background: #f1f1f1;
}

.lesson-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 15px rgba(0, 0, 0, 0.2);
}

.lesson-card h4 {
    margin-bottom: 1rem;
    color: #2c3e50;
}

.lesson-card p {
    margin-bottom: 1.5rem;
    color: #666;
}

/* Resources section */
.resources {
    padding: 3rem 0;
    background: #f1f8ff;
}

.resources h3 {
    text-align: center;
    margin-bottom: 2rem;
    font-size: 2rem;
    color: #2c3e50;
}

.resources-list {
    list-style: none;
    max-width: 600px;
    margin: 0 auto;
}

.resources-list li {
    margin-bottom: 1rem;
}

.resources-list a {
    color: #3498db;
    text-decoration: none;
    transition: color 0.3s;
}

.resources-list a:hover {
    color: #2980b9;
    text-decoration: underline;
}

/* Footer */
.footer {
    background: #2c3e50;
    color: white;
    text-align: center;
    padding: 2rem 0;
}

/* Responsive design */
@media (max-width: 768px) {
    .header .container {
        flex-direction: column;
        padding: 1rem;
    }
    
    .nav a {
        margin: 0.5rem 1rem;
    }
    
    .hero h2 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .lessons-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .hero {
        padding: 2rem 0;
    }
    
    .lesson-card {
        padding: 1.5rem;
    }
}