#back {
  position: absolute;
  width: 100%;
  z-index: -1;
}

#top-bar {
  padding-bottom: 14%;
  margin-bottom: 0;
}

h1, h2 {
  text-align:center;
}
.maindiv {
  padding-left:1.5%;
  border:solid 2px black;
  margin-right:-2px;
}

#download {
  position:absolute;
  margin-left: 2%;
  margin-top: 4%;
  border: solid black 1px;
  border-radius: 3px;
}