.submenu {
  display: none;
}

::selection {
  color: white;
  background: black;
}

#goTopBtn {
  position: fixed;
  bottom: 20px;
  right: 20px;
  display: none;

  padding: 10px 15px;
  border-radius: 5px;

  background: #333;
  color: #fff;
  font-size: 14px;
  text-decoration: none;

  z-index: 9999;
}