css属性，只有块级标签设计宽和高才会生效:
<!DOCTYPE html> <html lang="zh-CN"> <head> <meta charset="UTF-8"> <title>选择器的优先级</title> <link rel="stylesheet" href="zz.css" type="text/css"> <style> .c1 { width: 360px; height: 200px; background-color: #75b976;} span { width: 100px; height: 120px; background-color: #20201c; font-size: 44px; font-weight: 800; font-color: yellow; color: white; color:#FFFFFF; color:rgba(255,255,255,0.5) } a{ text-decoration: none; } </style> </head> <body> <div class="c1">div</div> <div>div1</div> <span>我是span</span> <a href="https://www.baidu.com">baidu</a> <p></p> </body> </html>
原文：https://www.cnblogs.com/yfjly/p/10926549.html