body {
  overflow: hidden;
  background: #ecf0f1;
  transition: background 0.5s;
  margin: 0;
}

#kh {
  opacity: 0;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  cursor: pointer;
  -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
  -webkit-tap-highlight-color: transparent;
  touch-action: none;
}