ff;

  line-height: 1.5em;
  text-align: center;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  -khtml-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;;

  cursor: pointer;
}

#menu {
  display: flex;
  flex-direction: column;
  width: 33%; height: 100vh;
  max-width: 500px;
  box-sizing: border-box;
  background-color: #ddd;
  overflow: hidden;
  transition: opacity 0.1s linear;
  padding: 0 5px;
  position: fixed;
  left: 0; top: 0;
  border-right: 