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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f8f9fa;
}

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

header {
    text-align: center;
    margin-bottom: 40px;
    padding: 40px 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 10px;
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

.header-links {
    margin-top: 20px;
    display: flex;
    gap: 15px;
    justify-content: center;
    flex-wrap: wrap;
}

.header-links .btn {
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.3);
}

.header-links .btn:hover {
    background-color: rgba(255, 255, 255, 0.3);
    border-color: rgba(255, 255, 255, 0.5);
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
}

.section {
    background: white;
    border-radius: 10px;
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.section h2 {
    color: #495057;
    margin-bottom: 20px;
    font-size: 1.8rem;
    border-bottom: 3px solid #667eea;
    padding-bottom: 10px;
}

.items-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
}

.item {
    border: 1px solid #e9ecef;
    border-radius: 8px;
    padding: 20px;
    transition: all 0.3s ease;
    background: #f8f9fa;
    display: flex;
    flex-direction: column;
}

.item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
    border-color: #667eea;
}

.item h3 {
    color: #495057;
    margin-bottom: 8px;
    font-size: 1.3rem;
}

.item i {
    color: #6c757d;
    font-size: 0.9rem;
    display: block;
    margin-bottom: 10px;
}

.item-links {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-top: auto;
    padding-top: 15px;
}

.btn {
    display: inline-block;
    padding: 8px 16px;
    border-radius: 5px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

.btn-primary {
    background-color: #667eea;
    color: white;
}

.btn-primary:hover {
    background-color: #5a6fd8;
}

.btn-secondary {
    background-color: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background-color: #5a6268;
}

.btn-outline {
    background-color: transparent;
    color: #667eea;
    border: 2px solid #667eea;
}

.btn-outline:hover {
    background-color: #667eea;
    color: white;
}

.pdf-icon::before {
    content: "📄 ";
}

.slides-icon::before {
    content: "🎤 ";
}

footer {
    text-align: center;
    padding: 20px;
    color: #6c757d;
    margin-top: 40px;
}

@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .items-grid {
        grid-template-columns: 1fr;
    }
}