JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <header><h1>Header</h1></header>
    <div id="body">Body</div>
    <footer><h3>Footer</h3></footer>
</div>

CSS

#container {
    width: 100%;
    height: 100%;
    display: flex;
    flex-direction: column;
    flex-wrap: nowrap;
}

header {
    flex-shrink: 0;
}
#body{
    flex-grow: 1;
    overflow: auto;
    min-height: 2em;
}
footer{
    flex-shrink: 0;
}