JSFiddle - React, Tailwind, and code Playground

by ecmanaut

HTML

<div class="wrapper">
  <header>
    A short header tab
  </header>
  <div class="body">
    Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
  </div>
</div>

CSS

body {
  background: #ffeeee;
}

header {
  border-radius: 10px 10px 0 0; /* round NW and NE corners */
  position: relative;
  padding-bottom: 0px;
  border: 1px solid black;
  border-bottom: 1px solid white;
  margin-bottom: -1px;
}

.body {
  border-radius: 0 10px 10px 10px; /* round NE SE SW corners */
  border: 1px solid black;
}

.wrapper {
  /* filter: drop-shadow(0 0 4px rgba(0, 0, 0, 0.4)); */
  margin: -1px;
}

header, .body {
  padding: 10px;
  background: white;
  display: inline-block;
}

/* white round SW round inside of elbow corner */
header::before {
  content: "";
  position: absolute;
  overflow: hidden;
  bottom: -10px;
  right: -10px;
  width: 0;
  height: 0;
  padding: 0 0 10px 10px;
  border-width: 0 0 10px 10px;
  border-radius: 0 0 0 30px;
  border-style: solid;
  border-color: white;
}

/* 1px black SW round inside of elbow border */
header::after {
  content: "";
  position: absolute;
  bottom: -1px;
  right: -11px;
  width: 0;
  height: 0;
  padding: 0 0 10px 10px;
  border-width: 0 0 1px 1px;
  border-radius: 0 0 0 10px;
  border-style: solid;
  border-color: black;
}