JSFiddle - React, Tailwind, and code Playground

HTML

<div id="header" style="height: 200px; border: 1px solid green">
    Something here
</div>

<div id="fill" style="border: 1px solid red">
    some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>    some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
        some content<br/>
</div>

CSS

#fill{
overflow: auto;   
}

JavaScript

$(document).ready(function() {

   sizeContent();


});

$(window).resize(sizeContent);


function sizeContent(){
    var top = $('#header').height();
    var height = $(window).height() - top - 30;
    
    

    
    
    $('#fill').height(height);
}