<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta http-equiv="X-UA-Compatible" content="IE=edge"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> <style> div { /* border 撑大盒子尺寸 */ /* 盒子尺寸 = width / height + 边框线 */ /* 如果400 * 400 尺寸 */ width: 380px; height: 380px; background-color: green; border: 10px solid #000; } </style> </head> <body> <div>div</div> </body> </html>
