<style>
div#t {
width: 200px;
height: 200px;
border: 20px solid rgba(255,0,0,1);
border-radius: 100px;
border-top-right-radius: 0px;
border-bottom-left-radius: 0px;
border-left-color: rgba(0,0,255,1);
background-color: green;
box-sizing: border-box;
margin: 20px;
border-top-width: 10px;
border-bottom-width: 10px;
border-left-width: 36px;
border-right-width: 0px;
}
</style>
<div id="t"></div>