body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 20px;
    transition: background-color 0.3s ease;
}

header {
    text-align: center;
    margin-bottom: 30px;
}

nav {
    background-color: #333;
    padding: 10px 0;
    border-radius: 5px;
    margin: 20px auto;
    max-width: 800px;
}

nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

nav li {
    display: inline;
}

nav a {
    color: white;
    text-decoration: none;
    padding: 8px 12px;
    border-radius: 4px;
    transition: background-color 0.3s ease;
}

nav a:hover {
    background-color: #555;
}

nav a.active {
    background-color: #4CAF50;
    font-weight: bold;
}

main {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

button {
    padding: 10px 20px;
    background-color: #4CAF50;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    margin-top: 20px;
}

button:hover {
    background-color: #45a049;
}

footer {
    text-align: center;
    margin-top: 30px;
    color: #666;
}

/* Responsive Design */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }
    
    nav {
        margin: 15px 0;
    }
    
    nav ul {
        gap: 10px;
        padding: 0 10px;
    }
    
    nav a {
        padding: 6px 10px;
        font-size: 14px;
    }
    
    main {
        padding: 0 10px;
    }
    
    h1 {
        font-size: 24px;
    }
    
    h2 {
        font-size: 20px;
    }
}

@media (max-width: 480px) {
    nav ul {
        flex-direction: column;
        align-items: center;
        gap: 5px;
    }
    
    nav a {
        display: block;
        width: 120px;
        text-align: center;
    }
    
    button {
        width: 100%;
        max-width: 200px;
    }
}