<html>
<head></head>

<body>
  <div class="box"></div>
  <p>chrome下效果更好</p>
</body>
</html>
.box 
{
  width:50px;
  height:50px;
  border-radius:50%;
  border:#000 solid 2px;
  outline:#000 solid 15px;
  outline-offset:-40px;
  transform:rotate(45deg);
}
View Compiled
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