<!DOCTYPE html>
<html lang="ru">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <div class="btn">
        <div class="element">
        </div>
    </div>
</body>
</html>
body {
  background-color: #a3d5d3;
}
*{
            box-sizing: border-box;
        }
        body{
            background-color:  #837F83;
        }
        .btn{
            width: 300px;
            height: 50px;
            border: rgb(255, 0, 0) 2px solid;
        }
        .element{
            display: flex;
            width: 46px;
            height: 46px;
            border: white 2px solid;
            border-radius: 30px;
            background-color: #fff;
            justify-content: center;
        }

External CSS

This Pen doesn't use any external CSS resources.

External JavaScript

This Pen doesn't use any external JavaScript resources.