JSFiddle - React, Tailwind, and code Playground

HTML

<div class="i-has-colourful-borders">
</div>

CSS

* {
    box-sizing: border-box;
}

.i-has-colourful-borders {
    border: 80px solid;
    border-top-color: red;
    border-right-color: blue;
    border-bottom-color: green;
    border-left-color: yellow;
    
    width: 100px;
    height: 100px;
}