Box model
<!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <title>盒子模型</title> <style> body { margin: 0; } .container { margin: 100px; } .bd { border-style: groove; } .pd { padding: 100px; } .content { background-color: blue; } </style> </head> <body> <div class="container"> <div class="bd"> <div class="pd"> <div class="content">hello</div> </div> </div> </div> </body> </html>