html {
  margin: 0;
  padding: 0;
  border-width: 0;
}

body {
  background-color: black;
}

section {
  visibility: hidden;
  background-color: black;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-size: cover;
}

video {
  width: 100%;
  max-height: 100%;
}

audio {
  position: fixed; /* or absolute */
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.present {
  visibility: visible;
}

.slidecenter {
  color: white;
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}
.slideinfo {
  color: white;
  left: 50%;
  text-align: center;
}
a:link,
a:visited {
  color: white;
  text-decoration: none;
}