body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f4f4f4;
}

header {
    background-color: #333;
    color: #fff;
    padding: 1em;
    text-align: center;
}

main {
    padding: 1em;
}

ul {
    list-style: none;
    padding: 0;
}

li {
    background-color: #fff;
    margin: 0.5em 0;
    padding: 1em;
    border-radius: 5px;
}

a {
    text-decoration: none;
    color: #333;
}