JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    
    <div id="leftblock">
        some stuff
    </div>
    
    <div id="contentblock">
        other stuff
    </div>
    
    <div id="rightblock">
        <div>more stuff</div>
        <div style="word-wrap:break-word; overflow: auto;">yeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeelp</div>
    </div>
    
    
</div>

CSS

#container {
    width: 100%;
    display: table;
    table-layout: fixed;
    border: 5px solid #ccc
}
#leftblock {
    display: table-cell;
    padding: 10px;
}
#contentblock {
    width: 100px;
    display: table-cell;
    padding: 0px;
    border: 5px solid #ccc;
    border-top: 0;
    border-bottom: 0;
}
#rightblock {
    position:fixed;
    display: table-cell;
    padding: 10px;
}