Border Radius in Maps?

I want to create a border radius like this as per in the image ? How can i do that !

https://codepen.io/nikhilrajnair/pen/ZMMNVQ

I don’t see anything in the codepen but looks like this property is doing it.

border-radius: 200vh 200vh 0% 0% / 40vh 140vh 0% 0%;

Yes but need to update the border radius like as per in the image