<style>
div#t {
width: 400px;
height: 400px;
border: double rgba(255,0,0,1);
border-width: 100px 139px;
border-radius: 200px / 100px;
border-left-color: rgba(0,0,255,1);
-moz-box-sizing: border-box;
box-sizing: border-box;
margin: 20px;
}
</style>
<div id="t"></div>