JSFiddle - React, Tailwind, and code Playground

by Roman Fedytskyi

HTML

<div class="block-main">
  
</div>

CSS

.block-main {
  height: 500px;
  background-color: blue;
  border-top-left-radius: 300px;
  margin-top: 200px;
}

.block-main::after {
  content: '';
  display: block;
  height: 200px;
  width: 500px;
  position: absolute;
  background-color: blue;
  border-radius: 300px;
  right: 0;
  top: 100px;
}