html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    text-align: center;
}
h1, h2, h3, h4, h5, strong {
    font-weight: normal;
    margin: 0;
}
pre, ul, ol {
    text-align: left;
}
blockquote {
    margin-left: 0;
    margin-right: 0;
    font-style: italic;
}
ul {
    margin: 0;
}
body > div {
    height: 100%;
    margin: 0 auto;
    -webkit-box-pack: center;
    -webkit-box-orient: vertical;
    -webkit-box-align: stretch;
    -moz-box-pack: center;
    -moz-box-orient: vertical;
    -moz-box-align: stretch;
    box-pack: center;
    box-orient: vertical;
    box-align: stretch;
    display: none;
    width: 70%;
}
body > div.current {
    display: -webkit-box;
    display: -moz-box;
    display: box;
}