#page_tree{
  width: 70%;
  z-index: 1000;
  top: 0px;

  max-height:90%;
  overflow-x: hidden;
  margin: auto;
}

body{
  background-image: url('https://media.giphy.com/media/Qwo19KznaE0Paz9YP7/giphy.gif');
  background-size: cover;
}