body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}
header {
    background-color: #003366;
    color: white;
    padding: 1em;
    text-align: center;
}
nav a {
    color: white;
    margin: 0 1em;
    text-decoration: none;
}
main {
    padding: 2em;
}
footer {
    background-color: #f0f0f0;
    text-align: center;
    padding: 1em;
    margin-top: 2em;
}
img {
    max-width: 100%;
    height: auto;
    margin: 1em 0;
}