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