JSFiddle - React, Tailwind, and code Playground

HTML

<!doctype html>
<meta charset="utf-8">
<title>Блок №2</title>
<div class="b2">
    <h2>Заголовок</h2>
    <div>
        <p>Содержимое</p>
    </div>
</div>

CSS

body { background: #fff; font: .75em/1.333 sans-serif; margin: 0; padding: 0; }
.b2 { margin: 12px;}
.b2 h2 { font-size: 1.25em; border-radius: 5px 5px 0 0; max-width: 250px; display: inline-block; position: relative; }
.b2 h2:after { content: ' '; display: block; position: absolute; top: 100%; left: 0; width: 110%; height: 5px; background: #dfc; z-index: 2; }
.b2>div { border-radius: 0 5px 5px 5px; min-height: 80px; }
.b2>div, .b2 h2 { padding: 4px 8px; background: #dfc; -moz-box-shadow: 0 0 4px #000; -webkit-box-shadow: 0 0 4px #000; box-shadow: 0 0 4px #000; }
p { margin: .667em 0; }