Template:Infobox book/styles.css

/* Title inside the box */
.ib-book .infobox-above {
  font-style: italic;          /* keep book titles italic */
  font-weight: bold;
  text-align: center;
  padding: 0.2em 0.5em;
  border-bottom: 1px solid #aaa; /* matches .infobox-below’s top border */
}

/* Option A (simple): just hide the old caption visually and from AT */
.ib-book caption.infobox-title { display: none; }