并集选择器：
写法：选择器+，+选择器+，...
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Document</title> 6 <style type="text/css"> 7 div,p,span,h1{ 8 font-size: 50px; 9 color: green; 10 background-color: pink; 11 width: 120px; 12 height: 120px; 13 } 14 15 </style> 16 </head> 17 <body> 18 <div>文件</div> 19 <p>选择</p> 20 <span>查看</span> 21 <h1>web</h1> 22 </body> 23 </html>