<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>css半圆弧线</title>
<style type="text/css">
.circle1 {
width: 100px;
height: 200px;
border: 1px solid black;
border-radius: 100% 0 0 100%/50%;
border-right: none;
}
.circle2 {
width: 200px;
height: 100px;
border: 1px solid black;
border-radius: 50% 50% 0 0/100% 100% 0 0;
border-bottom: none;
}
.circle3 {
width: 100px;
height: 200px;
border: 1px solid black;
border-radius: 0 100% 100% 0/50%;
border-left: none;
}
.circle4 {
width: 200px;
height: 100px;
border: 1px solid black;
border-radius: 0 0 50% 50%/0 0 100% 100% ;
border-top: none;
}
</style>
</head>
<body>
<ul>
<li><div class="circle1"></div></li>
<li><div class="circle2"></div></li>
<li><div class="circle3"></div></li>
<li><div class="circle4"></div></li>
</ul>
</body>
</html>
css半圆弧线
来源：https://www.cnblogs.com/wenxinsj/p/7448734.html