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

section {
    margin: auto;
    width: 900px;
}

h1 {
    text-align: center;
}

a {
    color: blue;
}

hr {
    border: 0;
    border-top: 1px solid gray;
}

#chart {
    width: 900px;
    height: 900px;
}

img {
    display: block;
    margin-left: auto;
    margin-right: auto;
}