<!DOCTYPE html> <html lang="zh-CN"> <head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> <style> body{ margin: 0; } .pg{ width: 100%; background-color: rebeccapurple; } @media (min- 666px) { .pg{ background-color: green; } } @media (min- 888px) { //大于 888 就红色 .pg{ background-color: red; } } </style> </head> <body> <div> <div class="pg">响应式布局</div> </div> </body> </html>