examples/curvedarrow.html

<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    #container {
      margin: 0 auto;
      padding: 30px 10px;
      text-align: center;
    }

    #curved {
      position: relative;
      width: 0;
      height: 0;
      border-top: 60px solid transparent;
      border-right: 60px solid black;
      transform: rotate(10deg);
      margin-left: 97px;
    }

    #curved:after {
      content: "";
      position: absolute;
      border: 0 solid transparent;
      border-top: 40px solid black;
      border-radius: 130px 0 0 0;
      top: -100px;
      left: -87px;
      width: 100px;
      height: 100px;
      transform: rotate(45deg);
    }
  </style>
</head>

<body>
  <div id="container">
    <div id="curved"></div>
  </div>
</body>

</html>