实例：纯CSS实现奥运五环
技术栈：HTML+CSS
效果：
源码：
【HTML】
<!DOCTYPE html>
<html lang="zh-CN">
<head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><title>纯CSS实现奥运五环</title><link rel="stylesheet" href="249.css">
</head>
<body><div class="rings"><div class="ring ring-blue"></div><div class="ring ring-yellow"></div><div class="ring ring-black"></div><div class="ring ring-green"></div><div class="ring rin
