Hi  florenz,
You can refer below using only css.
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
    <style type="text/css">
        .TextButton
        {
            text-decoration: none;
            background-color: Orange;
            color: #333333;
            padding: 2px 6px 2px 6px;
            border-top: 1px solid #CCCCCC;
            border-right: 1px solid #333333;
            border-bottom: 1px solid #333333;
            border-left: 1px solid #CCCCCC;
            border-radius: 8px;
        }
    </style>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <span class="TextButton">content</span>
    </div>
    </form>
</body>
</html>
 
Demo