代码如下：
<!DOCTYPE html> <html lang="en"> <head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta http-equiv="X-UA-Compatible" content="ie=edge"><title>Document</title><style>html, body {height: 100%;}.wrapper {position: relative;width: 100%;height: 100%;background: url("background.jpg") center no-repeat;background-size: cover;}.wrapper .login {position: absolute;width: 255px;height: 300px;top: 50%;left: 50%;transform: translate(-50%, -50%);background-color: #eee;}</style> </head> <body><div class="wrapper"><div class="login"></div></div> </body> </html>
