JSFiddle - React, Tailwind, and code Playground
HTML
<div class="top">
<div class="inner">
<svg
xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink"
viewBox='0 0 100 3.2' preserveAspectRatio="none">
<path fill-rule="evenodd" d="M0,0 L100,0 L50,40 Z" stroke-width="1px" stroke="#e5ecf3" fill="#E5ECF3" />
</svg>
</div>
</div>
CSS
body{margin:0;padding:0;background:orange;}
.top {position: absolute;width: 100%;}
.inner{height:0;position: relative;padding-top:3.2%;}
svg{height: 100%;display:block;width: 100%;position: absolute;top:0;left:0;}
rect{stroke:none;fill:teal;}