求助：如何实现横向Navbar在移动端转为幕帘式Overlay？

问题总结 #

• 原Navbar在全设备显示，小屏幕堆叠混乱
• 移动端幕帘Overlay未在小屏幕正常触发显示
• 尝试隐藏Navbar时错误覆盖了桌面端显示

无效尝试 #

• 将<img class="navi">和<span class="navi">移出容器后，双Navbar同时显示且可交互
• 直接用@media隐藏Navbar时，桌面端也被隐藏

预期目标 #

• 桌面端：显示带sticky属性的正常Navbar
• 移动端/平板端：隐藏原Navbar，显示由图片/文字按钮触发的幕帘Overlay，图片保持sticky

修正后代码 #

HTML #

<div>
  <!-- 桌面端Navbar -->
  <div class="navbar">
    <a type="text/html" href="/html/home.html" target="_parent">Home</a>
    <a type="text/html" href="/html/join.html" target="_parent">Join Us!</a>
    <a type="text/html" href="#" class="active">Chat Room</a>
    <a type="text/html" href="/html/showings.html" target="_parent">Showings</a>
    <a type="text/html" href="/html/gamerooms.html" target="_parent">Game Rooms</a>
    <a type="text/html" href="/html/openforuse.html" target="_parent">Open Link</a>
    <a type="text/html" href="/html/login.html" target="_parent" class="right">Login</a>
  </div>

  <!-- 移动端触发按钮 -->
  <div class="mobile-trigger">
    <img class="navi" src="/img/img/Navi.png" alt="Navi" onclick="openNav()" />
    <span class="navi" onclick="openNav()">Navigation</span>
  </div>

  <!-- 幕帘Overlay -->
  <div id="sideNav" class="overlay">
    <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
    <div class="overlay-content">
      <a type="text/html" href="/html/home.html" target="_parent">Home</a>
      <a type="text/html" href="/html/join.html" target="_parent">Join Us!</a>
      <a type="text/html" href="#" class="active">Chat Room</a>
      <a type="text/html" href="/html/showings.html" target="_parent">Showings</a>
      <a type="text/html" href="/html/gamerooms.html" target="_parent">Game Rooms</a>
      <a type="text/html" href="/html/openforuse.html" target="_parent">Open Link</a>
      <a type="text/html" href="/html/login.html" target="_parent">Login</a>
    </div>
  </div>
</div>
<script src="/js/mobile_menu.js"></script>

CSS #

/*//////////[ 桌面端Sticky NavBar ]//////////*/
.navbar {
  overflow: hidden;
  background-color: #3586ff;
  position: -webkit-sticky;
  position: sticky;
  top: 0;
  font-size: medium;
  z-index: 1000;
}

.navbar a {
  float: left;
  display: block;
  color: white;
  text-align: center;
  padding: 14px 20px;
  text-decoration: none;
}

.navbar a.right {
  float: right;
}

.navbar a:hover {
  background-color: #2a74e0;
  color: black;
}

.navbar a.active {
  background-color: #1f61c4;
  color: white;
}

/*//////////[ 移动端触发按钮 ]//////////*/
.mobile-trigger {
  display: none;
  background-color: #3586ff;
  position: -webkit-sticky;
  position: sticky;
  top: 0;
  z-index: 1000;
}

img.navi {
  width: 60px;
  height: auto;
  padding: 8px;
  cursor: pointer;
}

span.navi {
  font-size: medium;
  color: white;
  padding: 14px 20px;
  cursor: pointer;
  display: inline-block;
  vertical-align: middle;
}

/*//////////[ 幕帘Overlay ]//////////*/
.overlay {
  height: 100%;
  width: 0;
  position: fixed;
  z-index: 1001; /* 确保层级高于其他元素 */
  left: 0;
  top: 0;
  background-color: rgba(0, 0, 0, 0.9);
  overflow-x: hidden;
  transition: 0.5s;
}

.overlay-content {
  position: relative;
  top: 25%;
  width: 100%;
  text-align: center;
  margin-top: 30px;
}

.overlay a {
  padding: 8px;
  text-decoration: none;
  font-size: 36px;
  color: #818181;
  display: block;
  transition: 0.3s;
}

.overlay a:hover,
.overlay a:focus {
  color: #f1f1f1;
}

.overlay .closebtn {
  position: absolute;
  top: 20px;
  right: 45px;
  font-size: 60px;
}

/*//////////[ 媒体查询 - 适配移动端 ]//////////*/
/* 可根据需求调整断点，比如768px为平板/手机分界 */
@media screen and (max-width: 768px) {
  /* 隐藏桌面Navbar */
  .navbar {
    display: none;
  }
  /* 显示移动端触发按钮 */
  .mobile-trigger {
    display: block;
  }
}

@media screen and (max-height: 450px) {
  .overlay a {
    font-size: 20px
  }
  .overlay .closebtn {
    font-size: 40px;
    top: 15px;
    right: 35px;
  }
}

JS（无需修改） #

function openNav() {
  document.getElementById("sideNav").style.width = "100%";
}

function closeNav() {
  document.getElementById("sideNav").style.width = "0";
}

关键修改说明 #

1. HTML结构调整：将移动端触发按钮从Overlay容器中移出，避免被Overlay的width:0属性隐藏，确保小屏幕下能正常显示并触发事件
2. 媒体查询控制显示：添加@media screen and (max-width: 768px)断点，在小屏幕下隐藏桌面Navbar，显示移动端触发按钮；桌面端则反之
3. 层级优化：给Navbar、触发按钮和Overlay设置合理的z-index，确保Overlay能覆盖其他内容，同时触发按钮保持在顶部
4. 样式优化：调整触发按钮的布局，确保图片和文字垂直居中，保持与原Navbar一致的视觉风格

内容的提问来源于stack exchange，提问作者Ghost