make chapter headings use roboto slab also
body {
font-family: 'Roboto', sans-serif !important;
}
-.header-style, h1, h2, h3, h4, h5, h6 {
+.caption-text, .header-style, h1, h2, h3, h4, h5, h6 {
font-family: 'Roboto Slab', 'Roboto', sans-serif !important;
}
