Often need to round or rounded rectangle, then the code follows :( style and only small portions of code in the body)
<style>
{# D1
width: 200px;
height: 200px;
border: 2px solid #00f;
border-top-right-radius: 10%;
border-top-left-radius: 10%;
border-bottom-right-radius: 10%;
border-bottom-left-radius: 10%;
}
</style>
<body>
<div id="d1">
</div>
</body>