body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    margin: 0;
    padding: 0;
    line-height: 1.6;
    color: #333;
    background-color: #fafafa;
}
header {
    background: #0066cc;
    color: #fff;
    padding: 1rem 0;
    text-align: center;
}
header h1 {
    margin: 0;
}
nav ul {
    list-style: none;
    padding: 0;
    margin: 0.5rem 0 0;
    display: flex;
    justify-content: center;
    gap: 1.5rem;
}
nav a {
    color: #fff;
    text-decoration: none;
    font-weight: 500;
}
nav a:hover {
    text-decoration: underline;
}
main {
    max-width: 800px;
    margin: 2rem auto;
    padding: 0 1rem;
}
section {
    margin-bottom: 2rem;
}
section h2 {
    color: #0066cc;
    border-bottom: 2px solid #e0e0e0;
    padding-bottom: 0.3rem;
}
footer {
    text-align: center;
    padding: 1rem 0;
    margin-top: 2rem;
    color: #777;
    font-size: 0.9rem;
    border-top: 1px solid #eee;
}