使用Bootstrap中的.nav-stacked类垂直堆叠选项卡，
您可以尝试运行以下代码来实现.nav-stacked类减号。
<!DOCTYPE html> <html> <head> <title>Bootstrap Example</title> <link rel = "stylesheet" href = "https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css"> <script src = "https://cdn.staticfile.org/jquery/3.3.1/jquery.min.js"></script> <script src = "https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script> </head> <body> <div class = "container"> <h2>Database</h2> <p>The following are the database technologies:</p> <ul class = "nav nav-tabs nav-stacked" role = "tablist"> <li class = "active"><a href = "#">DB2</a></li> <li><a href = "#">MySQL</a></li> <li><a href = "#">SQL</a></li> <li><a href = "#">CouchDB</a></li> </ul> </div> </body> </html>