body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: #333;
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
    background-color: #f9f9f9;
}
h1, h2, h3 {
    color: #2c3e50;
}
a {
    color: #3498db;
    text-decoration: none;
}
a:hover {
    text-decoration: underline;
}
ul {
    padding-left: 20px;
}
li {
    margin-bottom: 10px;
}
p {
    margin-bottom: 15px;
}
header, footer {
    text-align: center;
    padding: 10px 0;
    border-top: 1px solid #eee;
    border-bottom: 1px solid #eee;
    margin: 20px 0;
}