我尝试复制一个主题切换器，就像你可以在Bootstrap网站的右上角看到的那样：

这里我的尝试：

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/js/bootstrap.bundle.min.js"></script>
<link href="https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css" rel="stylesheet" />

<svg xmlns="http://www.w3.org/2000/svg" style="display:none">
    <symbol id="moon-stars-fill" viewBox="0 0 16 16">
        <path d="M6 .278a.768.768 0 0 1 .08.858 7.208 7.208 0 0 0-.878 3.46c0 4.021 3.278 7.277 7.318 7.277.527 0 1.04-.055 1.533-.16a.787.787 0 0 1 .81.316.733.733 0 0 1-.031.893A8.349 8.349 0 0 1 8.344 16C3.734 16 0 12.286 0 7.71 0 4.266 2.114 1.312 5.124.06A.752.752 0 0 1 6 .278z"></path>
        <path d="M10.794 3.148a.217.217 0 0 1 .412 0l.387 1.162c.173.518.579.924 1.097 1.097l1.162.387a.217.217 0 0 1 0 .412l-1.162.387a1.734 1.734 0 0 0-1.097 1.097l-.387 1.162a.217.217 0 0 1-.412 0l-.387-1.162A1.734 1.734 0 0 0 9.31 6.593l-1.162-.387a.217.217 0 0 1 0-.412l1.162-.387a1.734 1.734 0 0 0 1.097-1.097l.387-1.162zM13.863.099a.145.145 0 0 1 .274 0l.258.774c.115.346.386.617.732.732l.774.258a.145.145 0 0 1 0 .274l-.774.258a1.156 1.156 0 0 0-.732.732l-.258.774a.145.145 0 0 1-.274 0l-.258-.774a1.156 1.156 0 0 0-.732-.732l-.774-.258a.145.145 0 0 1 0-.274l.774-.258c.346-.115.617-.386.732-.732L13.863.1z"></path>
    </symbol>
    <symbol id="sun-fill" viewBox="0 0 16 16">
        <path d="M8 12a4 4 0 1 0 0-8 4 4 0 0 0 0 8zM8 0a.5.5 0 0 1 .5.5v2a.5.5 0 0 1-1 0v-2A.5.5 0 0 1 8 0zm0 13a.5.5 0 0 1 .5.5v2a.5.5 0 0 1-1 0v-2A.5.5 0 0 1 8 13zm8-5a.5.5 0 0 1-.5.5h-2a.5.5 0 0 1 0-1h2a.5.5 0 0 1 .5.5zM3 8a.5.5 0 0 1-.5.5h-2a.5.5 0 0 1 0-1h2A.5.5 0 0 1 3 8zm10.657-5.657a.5.5 0 0 1 0 .707l-1.414 1.415a.5.5 0 1 1-.707-.708l1.414-1.414a.5.5 0 0 1 .707 0zm-9.193 9.193a.5.5 0 0 1 0 .707L3.05 13.657a.5.5 0 0 1-.707-.707l1.414-1.414a.5.5 0 0 1 .707 0zm9.193 2.121a.5.5 0 0 1-.707 0l-1.414-1.414a.5.5 0 0 1 .707-.707l1.414 1.414a.5.5 0 0 1 0 .707zM4.464 4.465a.5.5 0 0 1-.707 0L2.343 3.05a.5.5 0 1 1 .707-.707l1.414 1.414a.5.5 0 0 1 0 .708z"></path>
    </symbol>
    <symbol id="check2" viewBox="0 0 16 16">
        <path d="M13.854 3.646a.5.5 0 0 1 0 .708l-7 7a.5.5 0 0 1-.708 0l-3.5-3.5a.5.5 0 1 1 .708-.708L6.5 10.293l6.646-6.647a.5.5 0 0 1 .708 0z"></path>
    </symbol>
    <symbol id="circle-half" viewBox="0 0 16 16">
        <path d="M8 15A7 7 0 1 0 8 1v14zm0 1A8 8 0 1 1 8 0a8 8 0 0 1 0 16z"></path>
    </symbol>
</svg>

<nav class="navbar navbar-expand">
  <div class="container-fluid">
    <a class="navbar-brand" href="#">Navbar</a>
    <div class="navbar-collapse" id="navbarSupportedContent">
      <ul class="navbar-nav me-auto mb-2 mb-lg-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="#">Link</a>
        </li>

        <li class="nav-item dropdown">
          <button class="btn btn-link nav-link py-2 px-0 px-lg-2 dropdown-toggle d-flex align-items-center" id="bd-theme" type="button" aria-expanded="false" data-bs-toggle="dropdown" data-bs-display="static" aria-label="Toggle theme (dark)">
            <svg class="bi my-1 theme-icon-active">
              <use href="#moon-stars-fill"></use>
            </svg>
            <span class="d-lg-none ms-2" id="bd-theme-text">Toggle theme</span>
          </button>
          <ul class="dropdown-menu dropdown-menu-end" aria-labelledby="bd-theme-text">
            <li>
              <button type="button" class="dropdown-item d-flex align-items-center" data-bs-theme-value="light" aria-pressed="false">
                <svg class="bi me-2 opacity-50 theme-icon">
                  <use href="#sun-fill"></use>
                </svg>Light 
                <svg class="bi ms-auto d-none">
                  <use href="#check2"></use>
                </svg>
              </button>
            </li>
            <li>
              <button type="button" class="dropdown-item d-flex align-items-center active" data-bs-theme-value="dark" aria-pressed="true">
                <svg class="bi me-2 opacity-50 theme-icon">
                  <use href="#moon-stars-fill"></use>
                </svg>Dark 
                <svg class="bi ms-auto d-none">
                  <use href="#check2"></use>
                </svg>
              </button>
            </li>
            <li>
              <button type="button" class="dropdown-item d-flex align-items-center" data-bs-theme-value="auto" aria-pressed="false">
                <svg class="bi me-2 opacity-50 theme-icon">
                  <use href="#circle-half"></use>
                </svg>Auto 
                <svg class="bi ms-auto d-none">
                  <use href="#check2"></use>
                </svg>
              </button>
            </li>
          </ul>
      </ul>
    </div>
  </div>
</nav>

问题是图标是疯狂的巨大！如何使SVG图标适合导航栏的高度？