如何让Bootstrap导航栏切换器仅在sm断点显示，代码错误如何修正

问题原因 #

你当前代码缺少Bootstrap导航栏的响应式展开控制类，默认状态下导航栏会在所有屏幕尺寸保持折叠，所以汉堡切换器会一直显示，不会按断点自动隐藏。

修复方法 #

仅需调整2处代码即可匹配需求：

• 在<nav>标签的class属性中追加navbar-expand-sm，指定以sm（576px）为分界点：屏幕宽度≥576px时自动展开所有导航项、隐藏汉堡按钮；屏幕宽度<576px时隐藏导航项、显示汉堡按钮
• 可选优化：将ul标签的mb-2 mb-lg-0调整为mb-2 mb-sm-0，和sm断点保持统一，避免小屏到中屏过渡阶段出现多余下边距

修改后完整代码 #

<nav class="navbar navbar-expand-sm navbar-dark bg-dark">
  <div class="container-fluid">
    <a class="navbar-brand" href="#"> <img src="/Assets/LOGO.png" width="300" height="150" alt=""></a>
  <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target="#navbarSupportedContent" aria-controls="navbarSupportedContent" aria-expanded="false" aria-label="Toggle navigation">
    <span class="navbar-toggler-icon"></span>
  </button>
  <div class="collapse navbar-collapse" id="navbarSupportedContent">
    <ul class="navbar-nav me-auto mb-2 mb-sm-0">
      <li class="nav-item">
        <a class="nav-link active" aria-current="page" href="#">Home</a>
      </li>
      <li class="nav-item">
        <a class="nav-link" href="#">Our Apps</a>
      </li>
      <li class="nav-item dropdown">
        <a class="nav-link dropdown-toggle" href="#" id="navbarDropdown" role="button" data-bs-toggle="dropdown" aria-expanded="false">
          More
        </a>
        <ul class="dropdown-menu" aria-labelledby="navbarDropdown">
          <li><a class="dropdown-item" href="https://play.google.com/store/apps/dev?id=5447356877511937129">Google Play</a></li>
          <li><a class="dropdown-item" href="https://www.youtube.com/channel/UCVC1atDAYpvoHfTDjUij1PA">YouTube</a></li>
          <li><hr class="dropdown-divider"></li>
          <li><a class="dropdown-item" href="https://www.facebook.com/dyoll.lang">Facebook</a></li>
        </ul>
      </li>
    </ul>
  </div>
</div>
</nav>

内容的提问来源于stack exchange，提问作者Lloyd