    <!DOCTYPE html>
    <html>
    <head>
      <meta charset="UTF-8">
      <title>테두리 둥글게 만들기</title>
      <style>
        div {
          background: #cbeefe;
          width: 100px;
          height: 100px;
          line-height: 100px;
          text-align: center;
        }
      </style>
    </head>
    <body>
      <div style="border-radius: 10px">10px</div><br>
      <div style="border-radius: 20px 40px">20px 40px</div><br>
      <div style="border-radius: 20px 80px">20px 80px</div><br>
      <div style="border-radius: 50%">50%</div>
    </body>
    </html>