JSFiddle - React, Tailwind, and code Playground
by tabalinas
HTML
<div id=corner></div>
CSS
#corner{
border-top: 4px solid #007aff;
border-left: 4px solid #007aff;
width: 13px;
height: 13px;
transform:rotate(-45deg);
-ms-transform:rotate(-45deg); /* IE 9 */
-webkit-transform:rotate(-45deg); /* Safari and Chrome */
}