<!DOCTYPE html> <html> <head> <title></title> <meta charset="utf-8"> <meta name="viewport" content="width=device-width,initial-scale=1"> <link rel="stylesheet" href="https://unpkg.com/bootstrap@3.3.7/dist/css/bootstrap.min.css"> <link rel="stylesheet" href="https://unpkg.com/bootstrap@3.3.7/dist/css/bootstrap-theme.min.css"> <script src="https://unpkg.com/jquery@3.4.1/dist/jquery.min.js"></script> <script src="https://unpkg.com/bootstrap@3.3.7/dist/js/bootstrap.min.js"></script> </head> <body> <div class="container"> <h2 class="bg-primary">Hello World (bg-primary)</h2> <h2 class="bg-success">Hello World (bg-success)</h2> <h2 class="bg-info">Hello World (bg-info)</h2> <h2 class="bg-warning">Hello World (bg-warning)</h2> <h2 class="bg-danger">Hello World (bg-danger)</h2> </div> </body> </html>