JSFiddle - React, Tailwind, and code Playground

HTML

<div class="box">
	<div class="line"></div>
	<input type="text" value="Search" />
</div>

CSS

body {padding:50px;}
.box {width:205px; position:relative;}
	.line {width:1px; height:10px; background:#ff0000; position:absolute; left:0; bottom:0;}
	input {width:180px; background:#fff; color:#000; border:0; border-bottom:1px solid #ff0000; padding:5px 10px; position:absolute; left:1px; bottom:0;}