xaringanthemer/inst/resources/template_title-slide.css

.title-slide, .title-slide h1, .title-slide h2, .title-slide h3 {
  background-color: #fff !important;
  color: #222 !important;
}
.title-slide h3 {
  font-family: 'Roboto Condensed', 'Avenir Next', 'Helvetica Neue', 'Helvetica', sans-serif;
  font-weight: 400;
  padding-top: 15px;
  font-size: 28px;
}
.title-slide h3:nth-of-type(2) {
  margin-top: 10px;
  font-size: 28px;
}
.title-slide table {
  padding-top: 35px !important;
}
.title-slide i.fa {
  font-size: 2em;
}