JSFiddle - React, Tailwind, and code Playground

HTML

<div id="topbar">
    hello
</div>
<div class="sidebar">
    <div class="title">
        title
    </div>
    <div class="main">
        blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah 
    </div>
                
</div>
<div class="sidebar">
    <div class="title">
        title
    </div>
    <div class="main">
        blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah blah 
    </div>
                
</div>

CSS

#topbar {
    height: 40px;
    background-color: blue;
}

.sidebar {

width: 200px;

float: left;    
}

.title {
    height:30px;
    background-color: red;
}

.main {
    height: auto;
    overflow: scroll;
}