flex-sm-fill

html bootstrap5 Sample

ナビゲーション：flex

  <nav class="nav nav-pills flex-column flex-sm-row">
    <a class="flex-sm-fill text-sm-center nav-link active" href="#">アクティブ</a>
    <a class="flex-sm-fill text-sm-center nav-link" href="#">リンク</a>
    <a class="flex-sm-fill text-sm-center nav-link disabled" href="#">無効</a>
  </nav>