需要按钮来显示和隐藏覆盖导航

<button id="toggleNavButton">显示/隐藏导航</button>

#toggleNavButton {
  padding: 10px 20px;
  background-color: #0080ff;
  color: #fff;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}

#toggleNavButton:hover {
  background-color: #005cb3;
}

#navMenu {
  display: none;
}

#navMenu.visible {
  display: block;
}

document.getElementById("toggleNavButton").addEventListener("click", function() {
  var navMenu = document.getElementById("navMenu");
  if (navMenu.style.display === "none") {
    navMenu.classList.add("visible");
  } else {
    navMenu.classList.remove("visible");
  }
});