@page {
    margin: 5pt
    }
html, body {
    height: 100%;
    margin: 0;
    padding: 0;
    border-width: 0;
    oeb-column-number: 1
    }
.cover {
    text-align: center
    }
.cover_img {
    max-width: 100%;
    height: 100%
    }