JSFiddle - React, Tailwind, and code Playground

HTML

<div id="content">
        <div class="tri tri1"></div>
        <div class="tri tri2"></div>
        <div class="tri tri3"></div>
        <div id="rectangle"></div>
    </div>

CSS

#content{
            height:680px;
            background:black;
        }
/*??*/        
        .tri{
            width:0px;
            height:0px;
            border-style:dashed;
            border-width:50px;
            border-top-width:0px;
            border-color:green transparent;
            margin:auto;
        }
        .tri1{
            border-width:50px;
            border-top-width:0px;
        }
        .tri2{
            border-width:100px;
            border-top-width:0px;
        }        
        .tri3{
            border-width:150px;
            border-top-width:0px;
        }
/*?干*/
        #rectangle{
            width:90px;
            height:150px;
            background:#CC9900;
            margin:auto;
        }