<!DOCTYPE HTML> <html lang="en-US"> <head> <meta charset="UTF-8"> <title></title> </head> <body> <style type="text/css"> button{ width:32px; height:32px; border-radius:20px; outline:none; color:green; background:white; border:solid 1px green; cursor:pointer; font-size:18px; } </style> <button>+</button> </body> </html>
效果如图：