JSFiddle - React, Tailwind, and code Playground

HTML

<div class="border">solid green line with 5px width bot</div>
<br><br>
<div class="top-border">Red is up top</div>

CSS

.border{
  border-bottom: 5px solid #599a68;
}

.top-border{
  border-top: 5px solid red;
}