<!DOCTYPE html> <html> <head> <title></title> <meta charset="utf-8"> <style type="text/css"> .panel{ width: 100px; height: 100px; margin: 0 auto; background-color:"red"; } </style> </head> <body> <div class="panel"> <input type="text" name=""> <button>提交</button> </div> </body> </html>
