方式一：
<div style=" width: 50px; height: 50px; border: 13px solid orange; border-radius: 50px; clip-path: polygon(50% 0%, 100% 0%, 100% 3600%, 50% 50%); -webkit-clip-path: polygon(50% 0%, 100% 0%, 100% 3600%, 50% 50%); "></div>
效果：
方式二：
</head>
<style>
.circle {
position: relative;
box-sizing: border-box;
}
.big {
width: 140px;
height: 140px;
border-radius: 50%;
position: absolute;
margin: auto;
/*以下五個屬性為水平垂直居中的方法*/
left: 0;
top: 200px;
right: 0;
bottom: 0;
box-sizing: border-box;
}
.small {
width: 136px;
height: 136px;
border: 10px solid #9DDBE8;
border-radius: 50%;
position: absolute;
margin: auto;
/*以下五個屬性為水平垂直居中的方法*/
left: 0;
top: 200px;
right: 0;
bottom: 0;
box-sizing: border-box;
border-bottom-color: transparent;
}
</style>
</head>
<body>
<div class="circle">
<div class="big"></div>
<div class="small"></div>
</div>
</body>
效果：
