#grid {
    width: 660px;
    position: absolute;
    left: 50%;
    margin-left: -330px;
}

#grid div.vert.first-line {
    margin-left: 19px;
}

#grid div.vert {
    width: 139px;
    border: solid darkturquoise;
    border-width: 0 1px;
    margin-right: 19px;
}

#grid div.horiz {
    height: 19px;
    border-bottom: 1px dotted darkgray;
}