body {
    font-family: Arial, sans-serif;
    margin: 20px;
}
header {
    background: #eee;
    padding: 10px;
}
header nav a {
    margin: 0 10px;
}
table {
    border-collapse: collapse;
    width: 100%;
    margin-top: 10px;
}
table, th, td {
    border: 1px solid black;
    padding: 5px;
}