body {
    font-family: Arial, sans-serif;
    margin: 0;
}

header {
    background-color: lightblue;
    padding: 15px;
    text-align: center;
}

nav {
    background-color: lightgray;
    padding: 10px;
    text-align: center;
}

nav a {
    margin: 10px;
    text-decoration: none;
    color: black;
}

main {
    padding: 20px;
}

table {
    border-collapse: collapse;
    width: 50%;
}

table, th, td {
    border: 1px solid black;
}

th, td {
    padding: 8px;
}

footer {
    background-color: lightgray;
    text-align: center;
    padding: 10px;
    margin-top: 20px;
}