redoc/lib/components/SideMenuCat/side-menu-cat.css

label {
  font-weight: bold;
  font-size: 15px;
  cursor: pointer;
  color: #666;
}

ul {
  padding-left: 20px;
  margin: 0;
  height: 0;
  overflow: hidden;
}

ul.active {
  height: auto;
}

li {
  list-style: none inside none;
  padding: 5px 0;
  cursor: pointer;
}

label.active, li.active {
  color: #1976D3;
}