html,
body {
  overflow-x: hidden;
  overflow-y: hidden;
}
body {
  position: relative;
  touch-action: manipulation;
}
#demo-div {
  color: lightgrey;
  border-radius: 0.3rem;
}
#demo-div span,
#demo-div #num-observed-events {
  color: black;
}
h1 {
  margin-top: 0.5rem;
}
h4 {
  margin-top: 0.66rem;
  font-size: 1.33rem;
}
#demo-div li {
  line-height: 21px;
}
#demo-div ul {
  margin-bottom: 0.66rem;
}

#controller {
  background: #eee;
  width: 100%;
  height: 150px;
}