JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="header">Title</div> 
    <div class="body">Body</div>
</div>

CSS

.container{width: 100px; background: #333; font: 13px/130% Arial, sans-serif; border-radius: 10px; -moz-border-radius: 10px; }
.container .header{margin-left: 100px; width: 340px; height: 30px; background: #fff; border-radius: 0 0 0 10px; -moz-border-radius-bottomleft:10px; text-indent: -80px;
    color: #fff; line-height: 30px; z-index: 10; position: relative;
}                                  

.container .body{clear: left; width: 400px; height: 100px; background: #333; border-radius: 0 0 10px 10px; -moz-border-radius-bottomleft:10px; -moz-border-radius-bottomright:10px; margin-top: -10px; color: #fff; padding: 20px 0 0 20px;}