JSFiddle - React, Tailwind, and code Playground

HTML

<div class="transp">
    <div class="content">
        <div class="header">
            <h3>Заголовок</h3>
        </div>
        <p>
            Содержимое
        </p>
    </div>
</div>

CSS

body {background: url(http://stat18.privet.ru/lr/0a14282bf5911e622a90460d165d0307);}
.transp {
    height: 150px;
    border: 3px solid #112E1A;
    border-radius: 10px;
    background: rgba(46,124,69,0.7);
    padding: 10px;
}
.content {
    height: 147px;
    background: #E0EED6;
    border: 2px solid #616D57;
    border-radius: 10px;
    font: 13px/16px Arial;
}
.header {
    background: linear-gradient(to bottom, #FFD45F, #FFCE43, #FFBC00);
    border-radius: 10px 10px 0 0;.
    position: relative;
}
.header:after {
    content: '';
    position: absolute;
    left: 30px; 
    border: 10px solid transparent;
    

}
h3 {margin: 0;font-weight: normal;font-size: 130%;padding: 10px;}
p {padding-left: 10px;}