.masthead__menu-item > a.active {
  font-weight: bold;
}

.coauthor {
  font-size: 0.9em; /* or try 0.85em or 80% for smaller */
  color: #555;      /* optional: makes it a bit lighter */
}

.download-link {
  font-size: 0.9em;
  color: #3366cc;
  /* Optionally add: */
  /* font-style: italic; */
}