div.announce
{
    padding: 5px;
    background-color:lightgrey;
    border-color: black;
    border-width: 2px;
    border-style: solid;
}
div.attention
{
    padding: 5px;
    background-color:red;
    border-color: black;
    border-width: 2px;
    border-style: solid;
}
pre.code
{
    color: blue;
    font-family: courier;
    font-weight: bold;
    white-space: pre;
}
img.center
{
    display: block;
    margin-left: auto;
    margin-right: auto;
}