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

#top {
    text-align: center;
}

#topic {
    color: blue;
    display: inline-block;
    font-size: 32px;
    font-weight: bold;
    padding: 8px;
    margin-top: 16px;
}

#navigation a {
    color: blue;
    margin-top: 8px;
    margin-bottom: 8px
}

#navigation a:hover {
    color: blue
}

#image img {
    margin: auto
}

#main {
    width: 800px;
    margin: auto
}

#footer {
    text-align: center;
    color: gray;
    padding: 16px
    }