<!doctype html> <html lang="ko"> <head> <!-- Required meta tags --> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no"> <!-- Bootstrap CSS --> <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.0/dist/css/bootstrap.min.css" rel="stylesheet"> <title>Hello, world!</title> <style> .border{ border: solid 1px black; } </style> </head> <body> <h1>grid system</h1> <div class="container"> <div class="row"> <div class="col-md-6 col-md-6 border">hello</div> <div class="col-md-3 col-md-6 border">hello</div> <div class="col-md-3 col-md-6 border">hello</div> </div> <div class="row"> <div class="col-md-4 border">hello</div> <div class="col-md-4 border">hello</div> <div class="col-md-4 border">hello</div> </div> <div class="row"> <div class="col-md-4 offset-md-4 border">hello</div> <div class="col-md-4 border">hello</div> </div> </div> <!-- JavaScript --> <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.1.0/dist/js/bootstrap.bundle.min.js"></script> </body> </html>