JSFiddle - React, Tailwind, and code Playground

by grim

HTML

<body>
    <div id="container">
    </div>
</body>

CSS

body {
    background-color: green;
}

#container {
    background-color: black;
    position: relative;
    
    /* Arbitrary CSS properties for display */
    margin: 30px auto 10px;
    height: 150px;
    width: 80%;
}

#container::before {
    position: absolute;
    display: block;
    content: "";
    top: 0;
    left: 10%;
    
    /* following was generated from: http://apps.eky.hk/css-triangle-generator/ */
    width: 0px;
    height: 0px;
    border-style: solid;
    border-width: 17.3px 10px 0 10px;
    border-color: #008000 transparent transparent transparent;
    line-height: 0px;
    _border-color: #808000 #000000 #000000 #000000;
    _filter: progid:DXImageTransform.Microsoft.Chroma(color='#000000');
}