:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --text-color: #333;
    --bg-color: #f8f9fa;
    --border-color: #dee2e6;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-bottom: 2rem;
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

header p {
    font-size: 1.2rem;
    opacity: 0.9;
}

main {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

section {
    background: white;
    margin-bottom: 2rem;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

h2 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.8rem;
}

h3 {
    color: var(--secondary-color);
    margin-bottom: 0.8rem;
    font-size: 1.4rem;
}

ol, ul {
    margin-left: 2rem;
}

li {
    margin-bottom: 0.5rem;
}

#visualization {
    min-height: 400px;
    background: #f8f9fa;
    border: 2px dashed var(--border-color);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-top: 1rem;
}

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

/* Responsive Design */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }
    
    main {
        padding: 0 1rem;
    }
    
    section {
        padding: 1.5rem;
    }
}

/* animation for future interactive elements */
.fade-in {
    animation: fadeIn 0.5s ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}