body {
    margin: 0;
    font-family: Arial, sans-serif;
    background: #f4f4f4;
    color: #333;
}
header {
    text-align: center;
    padding: 40px 20px;
    background: #222;
    color: #fff;
}
header nav a {
    margin: 0 15px;
    color: #fff;
    text-decoration: none;
}
section {
    padding: 40px 20px;
    max-width: 900px;
    margin: auto;
    background: #fff;
    margin-top: 20px;
    border-radius: 10px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
}
h2 {
    margin-top: 0;
}
.btn {
    display: inline-block;
    padding: 10px 20px;
    background: #222;
    color: #fff;
    text-decoration: none;
    border-radius: 5px;
}
footer {
    text-align: center;
    padding: 20px;
    background: #222;
    color: #fff;
    margin-top: 30px;
}