JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
  <div class="container-header"><p class="ch"> Page</p></div>
</div>

CSS

#container {
    height: 300px;
    width: 400px;
    margin: auto;
    padding: auto;
    background-color: #00a7b5;
    border-radius: 50px 0px 0px 0px; 
    -moz-border-radius: 50px 0px 0px 0px; 
    -webkit-border-radius: 50px 0px 0px 0px; 
    border: 2px solid #00a7b5;
    overflow: hidden;
}

.container-header {

  width: 100%;
  height: 30px;
  background-color: #6cc249;
}

.ch {
  font-size: 14 px;
  font-weight: bold;
  color: white;
}