zebra/book/theme/css/custom.css

#service-dep-diagram {
    display: block;
    margin: 0px auto;
}

#service-dep-diagram a:hover {
    text-decoration: none;
    opacity: 0.65;
}

html.navy #service-dep-diagram, 
html.ayu #service-dep-diagram, 
html.coal #service-dep-diagram {
    filter: invert(1);
}