JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="content"></div>
    <div class="token"></div>
</div>

CSS

* {
    box-sizing: border-box;

}

html, body {
    height: 100%;
}

.container {
    height: 50vh;
    background: green;
    border:1px solid red;
}

.content{
    height:20px;
    background: blue;
}

.token{
    height:calc(100% - 20px);
    background: orange;
}