填空以创建在小屏幕上应变为垂直的导航栏
<nav class="@(6) @(16) bg-light"> <ul class="navbar-nav"> <li class="nav-item"> <a class="nav-link" href="#">链接 1</a> </li> <li class="nav-item"> <a class="nav-link" href="#">链接 2</a> </li> </ul> </nav>
<nav class="navbar navbar-expand-sm bg-light"> <ul class="navbar-nav"> <li class="nav-item"> <a class="nav-link" href="#">链接 1</a> </li> <li class="nav-item"> <a class="nav-link" href="#">链接 2</a> </li> </ul> </nav>